http://publicationslist.org/data/cornelia.denz/atom.xml Cornelia Denzhttp://publicationslist.org/cornelia.denz$basepathfavicon.icoRecent additions to Cornelia Denz's PublicationsList.org pagehttp://publicationslist.org/publications.png2012-01-03T12:32:27Z http://publicationslist.org/cornelia.denz/refid10 2012-01-03T12:31:14Z

We study numerically the effect of boundaries on Anderson localization of light in truncated two-dimensional photonic lattices in a nonlinear medium. We demonstrate suppression of Anderson localization at the edges and corners, so that stronger disorder is needed near the boundaries to obtain the same localization as in the bulk. We find that the level of suppression depends on the location in the...<br/><br/>Dragana M Jovic, Yuri S Kivshar, Cornelia Denz, Milivoj R Belic (2011) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 83: 3 <br/>

http://publicationslist.org/cornelia.denz/refid8 2012-01-03T12:31:14Z

We present a general comprehensive framework for the description of symmetries of complex light fields, facilitating the construction of sophisticated periodic structures carrying phase dislocations. In particular, we demonstrate the derivation of all three fundamental two-dimensional vortex lattices based on vortices of triangular, quadratic, and hexagonal shape, respectively. We show that these ...<br/><br/>Julian Becker, Patrick Rose, Martin Boguslawski, Cornelia Denz (2011) <i>OPTICS EXPRESS</i> <i></i> <i></i> 19: 10 9848-9862<br/>

http://publicationslist.org/cornelia.denz/refid11 2012-01-03T12:31:14Z

Physics of counterpropagating optical beams and spatial optical solitons is reviewed, including the formation of stationary states and spatiotemporal instabilities. First, several models describing the evolution and interactions between optical beams and spatial solitons are discussed, that propagate in opposite directions in nonlinear media. It is shown that coherent collisions between counterpro...<br/><br/>Milan S Petrovic, Milivoj R Belic, Cornelia Denz, Yuri S Kivshar (2011) <i>LASER & PHOTONICS REVIEWS</i> <i></i> <i></i> 5: 2 214-233<br/>

http://publicationslist.org/cornelia.denz/refid12 2012-01-03T12:31:14Z

We reveal a direct link between two fundamental wave phenomena in periodic media, Pendellosung oscillations and resonant coupling between spectral bands. We experimentally measure the power transfer between laser beams associated with the high-symmetry points in periodic and biased hexagonal photonic lattices. As a result, we demonstrate that Pendellosung oscillations dominate the dynamics of reso...<br/><br/>Bernd Terhalle, Anton S Desyatnikov, Dragomir N Neshev, Wieslaw Krolikowski, Cornelia Denz, Yuri S Kivshar (2011) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 106: 8 <br/>

http://publicationslist.org/cornelia.denz/refid13 2012-01-03T12:31:14Z

We introduce a generalized approach to generate an elementary nondiffracting beam, whose transverse intensity is distributed corresponding to a two-dimensional kagome structure. Furthermore, we present an effective experimental implementation via a computer controlled phase controlling spatial light modulator in combination with a specific Fourier filter system. Intensity and phase analysis of the...<br/><br/>Martin Boguslawski, Patrick Rose, Cornelia Denz (2011) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 98: 6 <br/>

http://publicationslist.org/cornelia.denz/refid7 2012-01-03T12:31:14Z

We investigate systematically the evolution of second harmonic generation in strontium barium niobate with different degrees of disorder of its chi(2) nonlinearity. These different degrees of disordered domain structures are achieved through electrically switching of the polarization at room temperature. The size and distribution of the domains change during the poling process and this in turn str...<br/><br/>Mousa Ayoub, Joerg Imbrock, Cornelia Denz (2011) <i>OPTICS EXPRESS</i> <i></i> <i></i> 19: 12 11340-11354<br/>

http://publicationslist.org/cornelia.denz/refid9 2012-01-03T12:31:14Z

Ince-Gaussian (IG) beams are a third complete family of solutions of the paraxial Helmholtz equation. While many applications of Hermite-Gaussian and Laguerre-Gaussian beams have been demonstrated for manipulation of microparticles, the potential of the more general class of IG beams has not yet been exploited at all. We describe the unique properties of IG beams with respect to optical trapping a...<br/><br/>Mike Woerdemann, Christina Alpmann, Cornelia Denz (2011) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 98: 11 <br/>

http://publicationslist.org/cornelia.denz/refid2 2012-01-03T12:31:14Z

In a numerical study, we demonstrate the dimensionality crossover in Anderson localization of light. We consider crossover from the two-dimensional (2D) to the one-dimensional (1D) lattice, optically induced in both linear and nonlinear dielectric media. The joint influence of nonlinearity and disorder on Anderson localization in such systems is discussed in some detail. We find that, in the linea...<br/><br/>Dragana M Jovic, Milivoj R Belic, Cornelia Denz (2011) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 84: 4 <br/>

http://publicationslist.org/cornelia.denz/refid6 2012-01-03T12:31:14Z

We demonstrate group-velocity control with an optically reconfigurable narrow-band filter at 1550 nm based on a volume-holographic Bragg grating. The filter is dynamically addressed to obtain different tunable magnitude and phase function by modification of the length, coupling strength, apodization, and phase discontinuities. We characterize the switching behavior, group-delay, electro-optical tu...<br/><br/>Wolfgang Horn, Sebastian Kroesen, Cornelia Denz (2011) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 98: 24 <br/>

http://publicationslist.org/cornelia.denz/refid3 2012-01-03T12:31:14Z

Computer-generated holograms displayed by phase-modulating spatial light modulators have become a well-established tool for beam shaping purposes in holographic optical tweezers. Still, the generation of light intensity patterns with high spatial symmetry and simultaneously without interfering ghost traps is a challenge. We have implemented an iterative Fourier transform algorithm that is capable ...<br/><br/>Christina Hesseling, Mike Woerdemann, Andreas Hermerschmidt, Cornelia Denz (2011) <i>OPTICS LETTERS</i> <i></i> <i></i> 36: 18 3657-3659<br/>

http://publicationslist.org/cornelia.denz/refid1 2012-01-03T12:31:14Z

We study experimentally and numerically the second-harmonic Cerenkov emission with two different characteristic azimuthal intensity distributions in strontium barium niobate with a random structure of chi(2) nonlinearity. We monitor in situ the Cerenkov emission during domain switching and show that a change of domain size and shape results in a fourfold azimuthal modulation of the Cerenkov cone. ...<br/><br/>Mousa Ayoub, Philip Roedig, Joerg Imbrock, Cornelia Denz (2011) <i>OPTICS LETTERS</i> <i></i> <i></i> 36: 22 4371-4373<br/>

http://publicationslist.org/cornelia.denz/refid4 2012-01-03T12:31:14Z

We present diverse reconfigurable complex 3D twister vortex superlattice structures in a large area embedded with tunable vortex spirals as well as dark rings, threaded by vortex helices. We demonstrate these tunable complex chiral vortex superlattices by the superposition of relatively phase engineered plane waves. The generated complex 3D twister lattice vortex structures are computationally as ...<br/><br/>Jolly Xavier, Sunil Vyas, Paramasivam Senthilkumaran, Cornelia Denz, Joby Joseph (2011) <i>OPTICS LETTERS</i> <i></i> <i></i> 36: 17 3512-3514<br/>

http://publicationslist.org/cornelia.denz/refid5 2012-01-03T12:31:14Z

We investigate discrete nondiffracting beams (DNBs) being the foundation of periodic and quasiperiodic intensity distributions. Besides the number of interfering plane waves, the phase relation among these waves is decisive to form a particular intensity lattice. In this manner, we systematize different classes of DNBs and present similarities as well as differences. As one prominent instance, we ...<br/><br/>Martin Boguslawski, Patrick Rose, Cornelia Denz (2011) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 84: 1 <br/>

http://publicationslist.org/cornelia.denz/refid21 2012-01-03T12:31:14Z

Dielectrophoretic forces originating from highly modulated electric fields can be used to trap particles on surfaces. An all-optical way to induce such fields is the use of a photorefractive material, where the fields that modulate the refractive index are present at the surface. We present a method for two-dimensional particle alignment on an optically structured photorefractive lithium niobate c...<br/><br/>Michael Esseling, Frank Holtmann, Mike Woerdemann, Cornelia Denz (2010) <i>OPTICS EXPRESS</i> <i></i> <i></i> 18: 16 17404-17411<br/>

http://publicationslist.org/cornelia.denz/refid22 2012-01-03T12:31:14Z

Experimental and numerical evidence of symmetry-breaking bifurcations of a circular dissipative soliton with additional boundary conditions in the feedback of a liquid crystal light valve are reported. By tuning the strength of the nonlinearity or the size of the additional boundaries, the circular structure breaks up into polygonal symmetries and the system exhibits multistability. The experiment...<br/><br/>M Ayoub, F Papoff, G L Oppo, C Denz (2010) <i>EUROPEAN PHYSICAL JOURNAL D</i> <i></i> <i></i> 59: 1 133-137<br/>

http://publicationslist.org/cornelia.denz/refid23 2012-01-03T12:31:14Z

The class of rod-shaped bacteria is an important example of non-spherical objects where defined alignment is desired for the observation of intracellular processes or studies of the flagella. However, all available methods for orientational control of rod-shaped bacteria are either limited with respect to the accessible rotational axes or feasible angles or restricted to one single bacterium. In t...<br/><br/>Florian Hoerner, Mike Woerdemann, Stephanie Mueller, Berenike Maier, Cornelia Denz (2010) <i>JOURNAL OF BIOPHOTONICS</i> <i></i> <i></i> 3: 7 468-475<br/>

http://publicationslist.org/cornelia.denz/refid25 2012-01-03T12:31:14Z

We realize an experimental control over the topological stability of three-lobe discrete vortex solitons by modifying the symmetry of a hexagonal photonic lattice optically induced in a photorefractive crystal. By continuously deforming the lattice wave in one transverse direction, we manipulate the coupling between lattice sites and induce or inhibit the reversal of soliton vorticity. (C) 2010 Op...<br/><br/>Bernd Terhalle, Dennis Goeries, Tobias Richter, Patrick Rose, Anton S Desyatnikov, Friedemann Kaiser, Cornelia Denz (2010) <i>OPTICS LETTERS</i> <i></i> <i></i> 35: 4 604-606<br/>

http://publicationslist.org/cornelia.denz/refid20 2012-01-03T12:31:14Z

We demonstrate slow and fast light at room temperature by dispersive phase-coupling in a photorefractive SBN:60 crystal. Non-degenerated wave-mixing is used to obtain delayed and amplified pulses with reduced or increased group velocity of v(g) = 0.2 cm s(-1) and v(g) = -1.3 cm s(-1), respectively. The gain spectrum is modulated by using multiple frequency shifted pumps simultaneously. The complet...<br/><br/>Wolfgang Horn, Jan V Bassewitz, Cornelia Denz (2010) <i>JOURNAL OF OPTICS</i> <i></i> <i></i> 12: 10, SI <br/>

http://publicationslist.org/cornelia.denz/refid26 2012-01-03T12:31:14Z

Complex reconfigurable 3D photonic quasicrystals (PQCs) are fabricated in nonlinear photorefractive strontium barium niobate by an optical phase-engineering-based single-step optical induction approach (see image). The approach demonstrates the embedded potential to use these structures as a reconfigurable platform for the investigation of advanced nonlinear light-matter interaction, or as templat...<br/><br/>Jolly Xavier, Martin Boguslawski, Patrick Rose, Joby Joseph, Cornelia Denz (2010) <i>ADVANCED MATERIALS</i> <i></i> <i></i> 22: 3 <br/>

http://publicationslist.org/cornelia.denz/refid24 2012-01-03T12:31:14Z

Reliable methods for the optical acquisition of three-dimensional (3D) coordinates like the fringe projection technique or 3D laser scanning are sensible to object movements because they require the recording of a sequence of images. In contrast, techniques using the projection of a random pattern reduce the measurement time to a single exposure time. A method is presented which allows the 3D acqu...<br/><br/>M Dekiff, P Berssenbruegge, B Kemper, C Denz, D Dirksen (2010) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 99: 3 449-456<br/>

http://publicationslist.org/cornelia.denz/refid15 2012-01-03T12:31:14Z

We quantitatively investigate the axial imaging properties of dynamic phase-contrast microscopy, with a special focus on typical combinations of tracer particles and magnifications that are used for velocimetry analysis. We show, for the first time, that a dynamic phase-contrast microscope, which is the integration of an all-optical novelty filter in a commercially available inverted microscope, c...<br/><br/>Michael Esseling, Frank Holtmann, Mike Woerdemann, Cornelia Denz (2010) <i>APPLIED OPTICS</i> <i></i> <i></i> 49: 31 6030-6038<br/>

http://publicationslist.org/cornelia.denz/refid14 2012-01-03T12:31:14Z

We present tailoring of three dimensional light fields which act as light moulds for elaborate particle micro structures of variable shapes. Stereo microscopy is used for visualization of the 3D particle assemblies. The powerful method is demonstrated for the class of propagation invariant beams, where we introduce the use of Mathieu beams as light moulds with non-rotationally-symmetric structure....<br/><br/>C Alpmann, R Bowman, M Woerdemann, M Padgett, C Denz (2010) <i>OPTICS EXPRESS</i> <i></i> <i></i> 18: 25 26084-26091<br/>

http://publicationslist.org/cornelia.denz/refid19 2012-01-03T12:31:14Z

Robert Boyd, Ortwin Hess, Corenelia Denz, Emmanuel Paspalkalis (2010) <i>JOURNAL OF OPTICS</i> <i></i> <i></i> 12: 10, SI <br/>

http://publicationslist.org/cornelia.denz/refid16 2012-01-03T12:31:14Z

Dissipative solitons are self-localized states which can exist anywhere in a system with translational symmetry, but in real systems this translational symmetry is usually broken due to parasitic inhomogeneities leading to spatial disorder, pinning the soliton positions. We discuss the effects of semiconductor growth induced spatial disorder on the operation of a cavity soliton laser based on a ve...<br/><br/>Neal Radwell, Patrick Rose, Carsten Cleff, Cornelia Denz, Thorsten Ackemann (2010) <i>OPTICS EXPRESS</i> <i></i> <i></i> 18: 22 23121-23132<br/>

http://publicationslist.org/cornelia.denz/refid18 2012-01-03T12:31:14Z

Organization and patterning of zeolite L crystals with their unique properties such as their one-dimensional nano channel system is of highest topical interest with various applications in many areas of science. We demonstrate full three-dimensional optical control of single zeolite L crystals and for the first time fully reversible, dynamic organization of a multitude of individually controlled z...<br/><br/>Mike Woerdemann, Stefan Glaesener, Florian Hoerner, Andre Devaux, Luisa De Cola, Cornelia Denz (2010) <i>ADVANCED MATERIALS</i> <i></i> <i></i> 22: 37 <br/>

http://publicationslist.org/cornelia.denz/refid17 2012-01-03T12:31:14Z

Counter-propagating optical traps are widely used where long working distances, axially symmetric trapping potentials, or standing light waves are required. We demonstrate that optical phase-conjugation can automatically provide a counter-propagating replica of a wide range of incident light fields in an optical trapping configuration. The resulting counter-propagating traps are self-adjusting and...<br/><br/>Mike Woerdemann, Konrad Berghoff, Cornelia Denz (2010) <i>OPTICS EXPRESS</i> <i></i> <i></i> 18: 21 22348-22357<br/>

http://publicationslist.org/cornelia.denz/refid32 2012-01-03T12:31:14Z

We report on the formation of spatial optical solitons in photorefractive media using picosecond laser pulses. Solitons are generated with laser pulses in the visible and infrared wavelength region using photorefractive strontium barium niobate. The dynamics of the soliton formation and the region of existence is studied in detail.<br/><br/>J Imbrock, C Heese, C Denz (2009) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 95: 2 261-268<br/>

http://publicationslist.org/cornelia.denz/refid33 2012-01-03T12:31:14Z

We report on the experimental observation of stable double-charge discrete vortex solitons generated in hexagonal photonic lattices created optically in self-focusing nonlinear media and show that single-charge vortex solitons are unstable in analogous conditions. Subsequently, we study, both theoretically and experimentally, the existence and stability of spatial vortex solitons in two-dimensiona...<br/><br/>Bernd Terhalle, Tobias Richter, Kody J H Law, Dennis Goeries, Patrick Rose, Tristram J Alexander, Panayotis G Kevrekidis, Anton S Desyatnikov, Wieslaw Krolikowski, Friedemann Kaiser, Cornelia Denz, Yuri S Kivshar (2009) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 79: 4, Part b <br/>

http://publicationslist.org/cornelia.denz/refid31 2012-01-03T12:31:14Z

A nonlinear dynamic phase-contrast stereoscope has been developed for the measurement of all three velocity components of a microfluidic flow field. The stereoscope system captures simultaneously two images of different off-axis views of the same region of interest in a microflow, seeded with tracer particles. Two independent photorefractive two-beam coupling novelty filters, one in each stereosco...<br/><br/>F Holtmann, M Oevermann, C Denz (2009) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 95: 3 633-636<br/>

http://publicationslist.org/cornelia.denz/refid36 2012-01-03T12:31:14Z

Cornelia Denz, Francesco Simoni (2009) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 11: 3 <br/>

http://publicationslist.org/cornelia.denz/refid34 2012-01-03T12:31:14Z

We demonstrate a dynamic phase contrast microscope based on photorefractive holographic interferometry. This system allows us to quantify concentration changes during micro-mixing processes by measuring the change of the optical path length. Therefore, no labelling processes with dyes or tracers are needed. The obtained interferograms are evaluated by an intensity analysis of every pixel, resultin...<br/><br/>Frank Holtmann, Mathias Eversloh, Cornelia Denz (2009) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 11: 3 <br/>

http://publicationslist.org/cornelia.denz/refid35 2012-01-03T12:31:14Z

We propose and demonstrate holographic phase contrast (HPC) as a new method to transfer a spatial phase distribution of arbitrary shape into a corresponding intensity pattern. A powerful application of HPC is the use in optical tweezers to dynamically control multiple traps like arrays or even more complex trapping geometries. Due to the image plane nature of HPC no hologram calculation is require...<br/><br/>Mike Woerdemann, Frank Holtmann, Cornelia Denz (2009) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 11: 3 <br/>

http://publicationslist.org/cornelia.denz/refid30 2012-01-03T12:31:14Z

We investigate non-volatile holographic data storage in photorefractive lithium niobate crystals. Infrared picosecond laser pulses are used to write holograms after sensitizing the crystal with blue light from a cw-laser. The dependence of the dynamic range and the photoconductivity on the pulse intensities and the recording wavelength is investigated in detail. The results can be explained by a t...<br/><br/>C Noelleke, J Imbrock, C Denz (2009) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 95: 3 391-397<br/>

http://publicationslist.org/cornelia.denz/refid28 2012-01-03T12:31:14Z

We experimentally investigate the formation of reconfigurable three-dimensional (3D) nonlinear photonic lattices in an externally biased cerium doped strontium barium niobate photorefractive crystal by a spatial light modulator-assisted versatile simplified single step optical induction approach. The analysis of the generated 3D nonlinear photonic lattices by plane wave guiding, momentum space spe...<br/><br/>Jolly Xavier, Patrick Rose, Bernd Terhalle, Joby Joseph, Cornelia Denz (2009) <i>OPTICS LETTERS</i> <i></i> <i></i> 34: 17 2625-2627<br/>

http://publicationslist.org/cornelia.denz/refid27 2012-01-03T12:31:14Z

We investigate the properties of angular momentum carrying vortex beams, reflected by a phase-conjugating mirror. It is shown that a self-pumped photorefractive phase-conjugating mirror is suitable to produce stable, high-fidelity phase conjugation of vortex beams. We prove that the topological charge of the vortex beam is maintained, and thus the angular momentum in the laboratory frame of refere...<br/><br/>Mike Woerdemann, Christina Alpmann, Cornelia Denz (2009) <i>OPTICS EXPRESS</i> <i></i> <i></i> 17: 25 22791-22799<br/>

http://publicationslist.org/cornelia.denz/refid29 2012-01-03T12:31:14Z

K Buse, C Denz, W Krolikowski (2009) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 95: 3 389-390<br/>

http://publicationslist.org/cornelia.denz/refid43 2012-01-03T12:31:14Z

We utilize the finite time constant of a photorefractive optical novelty filter microscope to access full-field velocity information of fluid flows on microscopic scales. In contrast to conventional methods such as particle image velocimetry and particle tracking velocimetry, not only image acquisition of the tracer particle field but also evaluation of tracer particle velocities is done all-optic...<br/><br/>Mike Woerdemann, Frank Holtmann, Cornelia Denz (2008) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 93: 2 <br/>

http://publicationslist.org/cornelia.denz/refid44 2012-01-03T12:31:14Z

We report on the first observation of topologically stable spatially localized multivortex solitons generated in optically induced hexagonal photonic lattices. We demonstrate that topological stabilization of such nonlinear localized states can be achieved through self-trapping of truncated two-dimensional Bloch waves and confirm our experimental results by numerical simulations of the beam propag...<br/><br/>Bernd Terhalle, Tobias Richter, Anton S Desyatnikov, Dragomir N Neshev, Wieslaw Krolikowski, Friedemann Kaiser, Cornelia Denz, Yuri S Kivshar (2008) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 101: 1 <br/>

http://publicationslist.org/cornelia.denz/refid45 2012-01-03T12:31:14Z

We realize an absolute position control of drifting dissipative optical solitons by injecting an incoherent amplitude parameter gradient onto the nonlinear optical system. This allows for two-dimensional, arbitrary control patterns. The control of the soliton drift velocity is studied applying a periodic, hexagonally shaped modulation. The guiding of dissipative solitons by one- and two-dimensiona...<br/><br/>Carsten Cleff, Bjoern Guetlich, Cornelia Denz (2008) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 100: 23 <br/>

http://publicationslist.org/cornelia.denz/refid42 2012-01-03T12:31:14Z

We present a technique that enables true associative data search in phase-encoded volume holographic storage systems. The technique overcomes crucial shortcomings related to the only two methods proposed for associative searches in phase-encoded systems so far. An additional interferometric readout during content addressing is utilized to ascertain the cross-correlations between an input informati...<br/><br/>G Berger, M Dietz, N Brauckmann, C Denz (2008) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 92: 2 145-152<br/>

http://publicationslist.org/cornelia.denz/refid46 2012-01-03T12:31:14Z

Overloaded phase codes for volume holographic data storage are introduced. In contrast to any previous phase-code design, overloaded phase codes enable multiplexing of a number of data pages that exceeds the number of utilized reference beams. In this way the achievable data capacity can be augmented. Overloaded codes are generated by extending multilevel phase codes based on the discrete Fourier ...<br/><br/>Gernot Berger, Mathias Dietz, Cornelia Denz (2008) <i>OPTICS LETTERS</i> <i></i> <i></i> 33: 11 1252-1254<br/>

http://publicationslist.org/cornelia.denz/refid47 2012-01-03T12:31:14Z

Synchronisation of spatiotemporal continuous disorder is realised in a Liquid Crystal Light Valve single feedback system with an incoherent, unidirectional master-slave-coupling scheme as excellent model system for synchronisation. Thus, complex states disordered in space and time were completely synchronised by using identical systems as master and slave. Thereby the impeding role of system diffe...<br/><br/>Katharina Havermann, Bjoern Guetlich, Cornelia Denz (2008) <i>JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS</i> <i></i> <i></i> 3: <br/>

http://publicationslist.org/cornelia.denz/refid40 2012-01-03T12:31:14Z

We control the emission properties of a broad-area vertical-cavity surface emitting laser by coupling it to an external feedback cavity containing a photorefractive crystal with an optically induced photonic lattice. The periodic modulation of the refractive index serves as a tunable filter and enables the dynamic suppression of unwanted spatial instabilities and modes, as originally suggested by ...<br/><br/>Bernd Terhalle, Neal Radwell, Patrick Rose, Cornelia Denz, Thorsten Ackemann (2008) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 93: 15 <br/>

http://publicationslist.org/cornelia.denz/refid41 2012-01-03T12:31:14Z

Karsten Buse, Cornelia Denz, Wieslaw Krolikowski (2008) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 92: 2 123-124<br/>

http://publicationslist.org/cornelia.denz/refid38 2012-01-03T12:31:14Z

We present an efficient method for optical induction of photonic superlattices in photorefractive media via holographic multiplexing. By superimposing phase engineered periodic waves of different periodicities, incremental recording of one- and two-dimensional multiperiodic lattices is demonstrated. The induced structures are subsequently analysed in Fourier space as well as in real space to verif...<br/><br/>Patrick Rose, Bernd Terhalle, Joerg Imbrock, Cornelia Denz (2008) <i>JOURNAL OF PHYSICS D-APPLIED PHYSICS</i> <i></i> <i></i> 41: 22 <br/>

http://publicationslist.org/cornelia.denz/refid37 2012-01-03T12:31:14Z

Bismuth tellurite is a photorefractive material for holographic data storage offering unique fixing capabilities. Important material and electro-optic properties obtained by four-wave-mixing and data storage experiments are reviewed and recent results concerning the applicability of bismuth tellurite for holographic data storage, including dynamic range, multiplexing capabilities and bit-error eva...<br/><br/>W Horn, I Foldvari, C Denz (2008) <i>JOURNAL OF PHYSICS D-APPLIED PHYSICS</i> <i></i> <i></i> 41: 22 <br/>

http://publicationslist.org/cornelia.denz/refid39 2012-01-03T12:31:14Z

Hybrid multinary block codes for implementation in page-oriented holographic storage systems are proposed. The codes utilize combined phase and amplitude modulations to encode input data. In comparison to pure amplitude-or pure phase-modulated block code designs hybrid multinary modulation coding allows us to augment the storage density at an unchanged error rate. Two different hybrid modulation c...<br/><br/>G Berger, M Dietz, C Denz (2008) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 10: 11 <br/>

http://publicationslist.org/cornelia.denz/refid52 2012-01-03T12:31:14Z

We experimentally investigate pump beam frequency detuning as a control technique in a photorefractive single-mirror feedback system exhibiting spontaneous self-organized transverse pattern formation with a regime of multistability. Deterministic switching between bistable patterns is demonstrated experimentally. An experimental stability analysis uncovers the effect of frequency detuning on the t...<br/><br/>Philip Jander, Christian Ripperda, Cornelia Denz (2007) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 24: 3 553-558<br/>

http://publicationslist.org/cornelia.denz/refid54 2012-01-03T12:31:15Z

B Terhalle, A S Desyatnikov, C Bersch, D Traeger, L Tang, J Imbrock, Y S Kivshar, C Denz (2007) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 86: 3 <br/>

http://publicationslist.org/cornelia.denz/refid53 2012-01-03T12:31:15Z

We study experimentally two-dimensional periodic photonic lattices optically imprinted in photorefractive nonlinear media, and explore the effect of anisotropy on the induced refractive-index patterns. The orientation anisotropy is demonstrated by comparing square and diamond lattices, while the polarization anisotropy is shown to distinguish ordinarily and extraordinarily polarized light. In part...<br/><br/>B Terhalle, A S Desyatnikov, C Bersch, D Traeger, L Tang, J Imbrock, Y S Kivshar, C Denz (2007) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 86: 3 399-405<br/>

http://publicationslist.org/cornelia.denz/refid51 2012-01-03T12:31:14Z

In biological fluid mechanics powerful imaging methods for flow analysis are required for making progress towards a better understanding of natural phenomena being optimised in the course of evolution. At the same time it is of crucial importance that the measuring and flow visualisation techniques employed guarantee biocompatibility, i.e. they do not distort the behaviour of biosystems. Unfortuna...<br/><br/>Hannes Petermeier, Wojciech Kowalczyk, Antonio Delgado, Cornelia Denz, Frank Holtmann (2007) <i>EXPERIMENTS IN FLUIDS</i> <i></i> <i></i> 42: 4 611-623<br/>

http://publicationslist.org/cornelia.denz/refid50 2012-01-03T12:31:14Z

We report on the stabilization of inherently unstable counterpropagating photorefractive spatial solitons by the use of one- and two-dimensional photonic lattices. We numerically investigate the dependence of the instability dynamics on period and amplitude of the lattice and present experimental verification for the dynamic stabilization of the bi-directional soliton state. (C) 2007 Optical Socie...<br/><br/>Sebastian Koke, Denis Trager, Philip Jander, Michael Chen, Dragomir N Neshev, Wieslaw Krolikowski, Yuri S Kivshar, Cornelia Denz (2007) <i>OPTICS EXPRESS</i> <i></i> <i></i> 15: 10 6279-6292<br/>

http://publicationslist.org/cornelia.denz/refid48 2012-01-03T12:31:14Z

We investigate the formation of fundamental discrete solitons and dipole-mode gap solitons in triangular photonic lattices imprinted in photorefractive nonlinear media. These lattices are strongly affected by the photorefractive anisotropy, resulting in orientation-dependent refractive index structures with reduced symmetry. It is demonstrated that two different orientations of the lattice wave en...<br/><br/>P Rose, T Richter, B Terhalle, J Imbrock, F Kaiser, C Denz (2007) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 89: 4 521-526<br/>

http://publicationslist.org/cornelia.denz/refid49 2012-01-03T12:31:14Z

We report on the experimental implementation of an external control for optical feedback solitons using incoherent spatial intensity distributions in a liquid crystal light valve (LCLV) optical single feedback system. The external control provides excellent experimental possibilities for static and dynamic control of the lateral positions of the optical feedback solitons which will be demonstrated...<br/><br/>Bjorn Guetlich, Holger Zimmermann, Carsten Cleff, Cornelia Denz (2007) <i>CHAOS</i> <i></i> <i></i> 17: 3 <br/>

http://publicationslist.org/cornelia.denz/refid59 2012-01-03T12:31:15Z

We predict theoretically and generate experimentally in photorefractive crystal two-dimensional self-trapped periodic waves of different symmetries, including vortex lattices-patterns of phase dislocations with internal energy flows. We demonstrate that these nonlinear waves exist with nonlocal nonlinearity even when the optically-induced periodic refractive index becomes highly anisotropic, and i...<br/><br/>A S Desyatnikov, N Sagemerten, R Fischer, B Terhalle, D Trager, D N Neshev, A Dreischuh, C Denz, W Krolikowski, Y S Kivshar (2006) <i>OPTICS EXPRESS</i> <i></i> <i></i> 14: 7 2851-2863<br/>

http://publicationslist.org/cornelia.denz/refid61 2012-01-03T12:31:15Z

We demonstrate theoretically and experimentally a novel type of localized beam supported by the combined effects of total internal and Bragg reflection in nonlinear two-dimensional square periodic structures. Such localized states exhibit strong anisotropy in their mobility properties, being highly mobile in one direction and trapped in the other, making them promising candidates for optical routi...<br/><br/>R Fischer, D Trager, D N Neshev, A A Sukhorukov, W Krolikowski, C Denz, Y S Kivshar (2006) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 96: 2 <br/>

http://publicationslist.org/cornelia.denz/refid58 2012-01-03T12:31:15Z

We propose a novel type of unitary matrix for phase-code multiplexed holographic memories, which could be quickly generated from geometric sequences. Our analysis shows that the phase-code matrices are unitary rather than orthogonal. The new matrices have complex elements. The order of unitary matrices can be any positive integer, so that we can accommodate the available spatial light modulators t...<br/><br/>X Z Zhang, G Berger, M Dietz, C Denz (2006) <i>OPTICS LETTERS</i> <i></i> <i></i> 31: 8 1047-1049<br/>

http://publicationslist.org/cornelia.denz/refid60 2012-01-03T12:31:15Z

We generate experimentally different types of two-dimensional Bloch waves of a square photonic lattice by employing the phase imprinting technique. We probe the local dispersion of the Bloch modes in the photonic lattice by analyzing the linear diffraction of beams associated with the high-symmetry points of the Brillouin zone, and also distinguish the regimes of normal, anomalous, and anisotropic...<br/><br/>D Trager, R Fischer, D N Neshev, A A Sukhorukov, C Denz, W Krolikowski, Y S Kivshar (2006) <i>OPTICS EXPRESS</i> <i></i> <i></i> 14: 5 1913-1923<br/>

http://publicationslist.org/cornelia.denz/refid57 2012-01-03T12:31:15Z

As the formation of spatial optical solitons in photorefractive mediad is governed by modification of the refractive index, every single solitons in complex configurations of solitons can act as a single waveguide for other light beams. In this article, we demonstrate guiding of amplitude-modulated beams in complex configurations of photorefractive solitons carrying information; we analyze the rec...<br/><br/>Denis Traeger, Nina Sagemerten, Cornelia Denz (2006) <i>IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS</i> <i></i> <i></i> 12: 3 383-387<br/>

http://publicationslist.org/cornelia.denz/refid55 2012-01-03T12:31:15Z

The cross-talk noise in phase encoded holographic memories employing unitary matrices is theoretically investigated. After reviewing some earlier work in this area, we derive a relationship for the noise-to-signal ratio for phase-code multiplexing with unitary matrices. The noise-to-signal ratio rises in a zigzag way on increasing the storage capacity. Cross-talk is mainly caused by high-frequency...<br/><br/>X Zhang, G Berger, M Dietz, C Denz (2006) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 85: 4 575-579<br/>

http://publicationslist.org/cornelia.denz/refid56 2012-01-03T12:31:15Z

We experimentally generate different types of two-dimensional self-trapped photonic lattices in a photorefractive medium and analyze the induced refractive index change using two different methods. One method gives the first experimental Fourier space analysis of both linear and nonlinear self-trapped photonic lattices with periodic phase modulation using partially spatially incoherent multiband e...<br/><br/>Bernd Terhalle, Denis Traeger, Liqin Tang, Joerg Imbrock, Cornelia Denz (2006) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 74: 5, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid67 2012-01-03T12:31:15Z

We demonstrate experimentally the existence of two transverse-dimensional counterpropagating (CP) incoherent spatial solitons in a 5 x 5 x 23 mm SBN:60Ce photorefractive crystal and investigate their dynamical behavior. We carry out numerical simulations that confirm our experimental findings. Substantially different behavior from the copropagating incoherent solitons is found. A symmetry breaking...<br/><br/>M Petrovic, D Jovic, M Belic, J Schroder, P Jander, C Denz (2005) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 95: 5 <br/>

http://publicationslist.org/cornelia.denz/refid68 2012-01-03T12:31:15Z

We report on the detailed experimental determination of the threshold for modulational instability in a photorefractive single-mirror feedback system using a Fourier control technique. Results are compared to analytical predictions and a disagreement for the experimentally significant multiple pattern region is found. Implications for the generation of nonhexagonal two-dimensional patterns are dis...<br/><br/>O Kamps, P Jander, C Denz (2005) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 72: 1, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid70 2012-01-03T12:31:15Z

We analyze theoretically and generate experimentally two-dimensional nonlinear lattices with periodic phase modulation in a photorefractive medium. The light-induced periodically modulated nonlinear refractive index is highly anisotropic and nonlocal, and it depends on the lattice orientation relative to the crystal axis. We discuss the stability of such induced photonic structures and their guidi...<br/><br/>A S Desyatnikov, D N Neshev, Y S Kivshar, N Sagemerten, D Trager, J Jagers, C Denz, Y V Kartashov (2005) <i>OPTICS LETTERS</i> <i></i> <i></i> 30: 8 869-871<br/>

http://publicationslist.org/cornelia.denz/refid66 2012-01-03T12:31:15Z

In this letter we present a technique which employs a photorefractive lithium-niobate crystal for novelty filtering. Due to the minimal trail formation exhibited by this novelty filter, it can be used for reliable quantitative phase measurement for time intervals of the order of a few hours. We present a simplified theoretical description of this filter based on a coupled wave theory [N. V. Kukhta...<br/><br/>V V Krishnamachari, O Grothe, H Deitmar, C Denz (2005) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 87: 7 <br/>

http://publicationslist.org/cornelia.denz/refid69 2012-01-03T12:31:15Z

We experimentally observed a counterpropagating dipole-mode vector soliton in a photorefractive SBN:60Ce crystal. We investigated the transient formation dynamics and show that the formation process differs significantly from the copropagating geometry. The experimental results are compared with fully anisotropic numerical simulations and show good qualitative agreement. (c) 2005 Optical Society o...<br/><br/>J Schroder, P Jander, C Denz, T Richter, K Motzek, F Kaiser (2005) <i>OPTICS LETTERS</i> <i></i> <i></i> 30: 9 1042-1044<br/>

http://publicationslist.org/cornelia.denz/refid64 2012-01-03T12:31:15Z

Due to modulation instability partially incoherent optical beams break up into stripe filaments in noninstantaneous media at a first threshold. We numerically and experimentally report on the formation of two-dimensional filaments at a secondary threshold, if increasing the nonlinearity further, which is due to material anisotropy. Particularly, we investigate the dependence of this secondary modu...<br/><br/>B Gutlich, T Konig, C Denz, K Motzek, F Kaiser (2005) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 255: 1-3 57-64<br/>

http://publicationslist.org/cornelia.denz/refid71 2012-01-03T12:31:15Z

We report on the experimental observation of a dynamic instability in the interaction of counterpropagating self-trapped beams in a photorefractive strontium barium niobate crystal. While the interaction of copropagating spatial optical solitons exhibits only transient dynamics, resulting in a final steady state, the counterpropagating geometry supports a dynamic instability mediated by intrinsic ...<br/><br/>P Jander, J Schroder, C Denz, M Petrovic, M R Belic (2005) <i>OPTICS LETTERS</i> <i></i> <i></i> 30: 7 750-752<br/>

http://publicationslist.org/cornelia.denz/refid62 2012-01-03T12:31:15Z

Dynamical behavior of counterpropagating (CP) mutually incoherent vector solitons in a 5 x 5 x 23 mm SBN: 60Ce photorefractive crystal is investigated. Experimental study is carried out, displaying rich dynamics of three-dimensional CP solitons and higher-order multipole structures, and a theory formulated that is capable of capturing such dynamics. We find that our numerical simulations agree wel...<br/><br/>D Jovic, M Petrovic, M Belic, J Schroeder, P Jander, C Denz (2005) <i>OPTICS EXPRESS</i> <i></i> <i></i> 13: 26 10717-10728<br/>

http://publicationslist.org/cornelia.denz/refid63 2012-01-03T12:31:15Z

Under feedback extended nonlinear optical systems spontaneously show a variety of periodic patterns and structures. Control gives new insight into these phenomena and it can open the way for potential application of nonlinear optical structures. We briefly review methods to control localized states in single feedback experiments. Application of a Fourier control method allows to modify interaction...<br/><br/>B Gutlich, H Zimmermann, C Denz, R Neubecker, M Kreuzer, T Tschudi (2005) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 81: 7 927-936<br/>

http://publicationslist.org/cornelia.denz/refid65 2012-01-03T12:31:15Z

We investigate the characteristics of correlation signals accomplished by content addressing in a phase encoded volume holographic storage system under different realistic conditions. In particular, we explore two crucial cases with respect to the structure of the data. The first one deals with a scenario where only partial or defective data are available for content addressing. The second case ta...<br/><br/>G Berger, M Stumpe, M Hohne, C Denz (2005) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 7: 10 567-575<br/>

http://publicationslist.org/cornelia.denz/refid72 2012-01-03T12:31:15Z

We demonstrate that two-dimensional two-component bright solitons of an annular shape, carrying vorticities (m,+/- m) in the components, may be stable in media with the cubic-quintic nonlinearity, including the hidden-vorticity (HV) solitons of the type (m,-m), whose net vorticity is zero. Stability regions for the vortices of both (m,+/- m) types are identified for m=1, 2, and 3, by dint of the c...<br/><br/>A S Desyatnikov, D Mihalache, D Mazilu, B A Malomed, C Denz, F Lederer (2005) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 71: 2, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid73 2012-01-03T12:31:15Z

We formulate an anisotropic nonlocal theory of the space charge field induced by. the coherent counterpropagating beams in biased photorefractive crystals. We establish that the competition between the drift and diffusion terms has to be taken into account when the crystal (c) over cap axis is tilted with respect to the propagation direction of the beams. We demonstrate that this configuration com...<br/><br/>K Motzek, M Belic, T Richter, C Denz, A Desyatnikov, P Jander, F Kaiser (2005) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 71: 1, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid77 2012-01-03T12:31:15Z

We describe different types of self-trapped optical beam carrying phase dislocations, including vortex solitons and ring-like soliton clusters. We demonstrate numerically how to create such nonlinear singular beams from the interaction of several fundamental optical solitons. Mutual trapping of several solitons can be regarded as a synthesis of ‘soliton molecules’, and it corresponds to a tran...<br/><br/>A Desyatnikov, C Denz, Y Kivshar (2004) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 6: 5 <br/>

http://publicationslist.org/cornelia.denz/refid79 2012-01-03T12:31:15Z

We study numerically the counterpropagating vector solitons in SBN:60 photorefractive crystals. A simple theory is provided for explaining the symmetry-breaking transverse instability of these solitons. Phase diagram is produced that depicts the transition from stable counterpropagating solitons to bidirectional waveguides to unstable optical structures. Numerical simulations are performed that pr...<br/><br/>M Belic, M Petrovic, D Jovic, A Strinic, D Arsenovic, K Motzek, F Kaiser, P Jander, C Denz, M Tlidi, P Mandel (2004) <i>OPTICS EXPRESS</i> <i></i> <i></i> 12: 4 708-716<br/>

http://publicationslist.org/cornelia.denz/refid76 2012-01-03T12:31:15Z

A wealth of periodic transverse patterns is observed in nonlinear optical, photorefractive single-feedback systems. It is the extension of a photorefractive medium in the direction of propagation of the laser beam that allows for the formation of stable hexagons, squares, rhombuses and dodecagons above the first bifurcation of the system. In this article we review the formation of these periodic p...<br/><br/>C Denz, P Jander, M Schwab, O Sandfuchs, M Belic, F Kaiser (2004) <i>ANNALEN DER PHYSIK</i> <i></i> <i></i> 13: 7-8 391-402<br/>

http://publicationslist.org/cornelia.denz/refid78 2012-01-03T12:31:15Z

A time-dependent model for the formation of self-trapped optical beams in photorefractive media by counterpropagating laser beams is analysed. It is shown that dynamically the beams may form stable steady-state structures or display periodic and irregular temporal behaviour. Steady-state solutions of non-uniform cross section are found, representing a general class of self-trapped waveguides, that...<br/><br/>M Belic, P Jander, K Motzek, A Desyatnikov, D Jovic, A Strinic, M Petrovic, C Denz, F Kaiser (2004) <i>JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 6: 5 <br/>

http://publicationslist.org/cornelia.denz/refid75 2012-01-03T12:31:15Z

A photorefractive-based novelty filter microscope can be used for real-time phase measurement of phase changes, introduced by moving objects or microorganisms, from 0 to pi radians. In this article, we propose a method to extend the phase-measurement range over the entire 2pi radians and demonstrate its validity both experimentally and numerically. Our method makes use of the fact that the slopes ...<br/><br/>V V Krishnamachari, C Denz (2004) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 79: 4 497-501<br/>

http://publicationslist.org/cornelia.denz/refid74 2012-01-03T12:31:15Z

We suggest a novel type of composite spatial optical soliton created by a coherent vortex beam guiding a partially incoherent light beam in a self-focusing nonlinear medium. We show that the incoherence of the guided mode may enhance, rather than suppress, the vortex azimuthal instability, and we also demonstrate strong destabilization of dipole-mode solitons by partially incoherent light. (C) 200...<br/><br/>K Motzek, F Kaiser, J R Salgueiro, Y Kivshar, C Denz (2004) <i>OPTICS LETTERS</i> <i></i> <i></i> 29: 19 2285-2287<br/>

http://publicationslist.org/cornelia.denz/refid89 2012-01-03T12:31:15Z

We study, both theoretically and experimentally, the scattering properties of optical dipole-mode vector solitons-radially asymmetric composite self-trapped optical beams. First, we analyze the soliton collisions in an isotropic two-component model with a saturable nonlinearity, and demonstrate that in many cases the scattering dynamics of the dipole-mode solitons allows us to classify them as “...<br/><br/>W Krolikowski, G McCarthy, Y S Kivshar, C Weilnau, C Denz, J J Garcia-Ripoll, V M Perez-Garcia (2003) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 68: 1, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid88 2012-01-03T12:31:15Z

A time-dependent model for the generation of joint waveguides by counterpropagating light beams in photorefractive crystals is introduced. Depending on initial conditions and parameter values, the beams form stable structures or display periodic and irregular dynamics. Steady-state solutions nonuniform in the direction of propagation are found, representing a general class of self-trapped waveguid...<br/><br/>M Belic, P Jander, A Strinic, A Desyatnikov, C Denz (2003) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 68: 2, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid90 2012-01-03T12:31:15Z

We discuss the creation of. an array of 9 x 9 photorefractive spatial screening solitons in a strontium barium niobate crystal. We investigate the waveguide properties of each channel with a beam of different wavelength and find that the waveguides guide the probe beam independently. A supplementary beam is used to influence the paths of the array solitons and to effectively combine two channels b...<br/><br/>J Petter, J Schroder, D Trager, C Denz (2003) <i>OPTICS LETTERS</i> <i></i> <i></i> 28: 6 438-440<br/>

http://publicationslist.org/cornelia.denz/refid92 2012-01-03T12:31:15Z

C Denz, M Schwab, C Weilnau (2003) <i></i> <i>TRANSVERSE-PATTERN FORMATION IN PHOTOREFRACTIVE OPTICS</i> <i></i> 188: 1-10<br/>

http://publicationslist.org/cornelia.denz/refid86 2012-01-03T12:31:15Z

We investigate the interaction of two-dimensional solitons propagating at small angles in a photorefractive crystal. We observe fusion of the beams when the intersecting angle is lower than some critical value. We measure the critical angle for fusion for different relative phase relations of the beams and demonstrate how this effect can be used to steer and switch the propagation of an additional...<br/><br/>G McCarthy, T Breuninger, J Schroder, C Denz, D Neshev, W Krolikowski (2003) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 77: 4 421-426<br/>

http://publicationslist.org/cornelia.denz/refid91 2012-01-03T12:31:15Z

We present a review of recent works on spatial optical solitons; in photorefractive media. We discuss fundamental properties of screening solitons and their interaction.<br/><br/>W Krolikowski, B Luther-Davies, C Denz (2003) <i>IEEE JOURNAL OF QUANTUM ELECTRONICS</i> <i></i> <i></i> 39: 1 3-12<br/>

http://publicationslist.org/cornelia.denz/refid87 2012-01-03T12:31:15Z

A photorefractive two-beam-coupling based novelty filter is sensitive to amplitude and phase changes. However, the phase sensitivity of this device has remained unexploited until now. In this paper we develop and demonstrate a method to overcome the effects of contour formation in novelty filter output and consequently employ the novelty filter as a quantitative real-time transient phase-measuring...<br/><br/>V V Krishnamachari, C Denz (2003) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 5: 5 <br/>

http://publicationslist.org/cornelia.denz/refid80 2012-01-03T12:31:15Z

We display rich spatial and temporal dynamics of light fields counterpropagating in a saturable self-focusing medium numerically, and analyze instabilities that counterpropagating solitons experience. An expression for the maximum length that the medium must not exceed for the solitons to be stable is derived and connected to the coupling strength of beam interaction. The instability can lead to p...<br/><br/>K Motzek, P Jander, A Desyatnikov, M Belic, C Denz, F Kaiser (2003) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 68: 6, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid85 2012-01-03T12:31:15Z

We introduce novel optical solitons that consist of a periodic and a spatially localized component coupled nonlinearly via cross-phase modulation. The spatially localized optical field can be treated as a gap soliton supported by the optically induced nonlinear grating. We find different types of these band-gap composite solitons and demonstrate their dynamical stability.<br/><br/>A S Desyatnikov, E A Ostrovskaya, Y S Kivshar, C Denz (2003) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 91: 15 <br/>

http://publicationslist.org/cornelia.denz/refid81 2012-01-03T12:31:15Z

Two-dimensional spatial solitonic lattices are generated and investigated experimentally and numerically in a Sr(x)Ba(1-x)Nb(2)O(6):Ce crystal. An enhanced stability of these lattices is achieved by exploiting the anisotropy of coherent soliton interaction, in particular the relative phase between soliton rows. The manipulation of individual soliton channels is achieved by the use of supplementary...<br/><br/>M Petrovic, D Trager, A Strinic, M Belic, J Schroder, C Denz (2003) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 68: 5, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid82 2012-01-03T12:31:15Z

Large two-dimensional spatial soliton arrays are generated experimentally and numerically in photorefractive media and their waveguiding properties at red and infrared wavelengths are demonstrated. An enhanced stability of solitonic lattices is achieved by exploiting the anisotropy of coherent soliton interaction and by controlling the relative phase between soliton rows. Manipulation of individua...<br/><br/>D Trager, A Strinic, J Schroder, C Denz, M Belic, M Petrovic, S Matern, H G Purwins (2003) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 5: 6 <br/>

http://publicationslist.org/cornelia.denz/refid83 2012-01-03T12:31:15Z

We report on the stable self-focusing of light for various degrees of spatial coherence. Since the diffraction of a partially spatial coherent light beam is mainly governed by the transverse correlation width, its self-focusing is generally non-trivial. Here, we systematically demonstrate that partially coherent solitons can be generated in a non-instantaneous nonlinear material when the external ...<br/><br/>C Weilnau, C Denz (2003) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 5: 6 <br/>

http://publicationslist.org/cornelia.denz/refid84 2012-01-03T12:31:15Z

We investigate the durability of volume holograms in bismuth tellurite crystals, Bi2TeO5. This material enables self-fixing of holograms during the recording process rendering any further fixing technique unnecessary. Therefore the material overcomes the vulnerability of holograms which is a typical inconvenient property of inorganic storage crystals. The quality reduction of reconstructed analogu...<br/><br/>G Berger, C Denz, I Foldvari, A Peter (2003) <i>JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS</i> <i></i> <i></i> 5: 6 <br/>

http://publicationslist.org/cornelia.denz/refid98 2012-01-03T12:31:15Z

Bismuth tellurite - Bi2TeO5 is a new photorefractive material recently available for optical memory investigations. Analogue volume holograms of a two-dimensional test pattern were recorded in undoped Bi2TeO5 crystals by using a cw Nd:YAG laser at 532 nm. The quality, dark decay and durability during permanent reading of the image were studied and compared to those of the reference LiNbO3 :Fe crys...<br/><br/>I Foldvari, C Denz, G Berger, A Peter (2002) <i>RADIATION EFFECTS AND DEFECTS IN SOLIDS</i> <i></i> <i></i> 157: 6-12 1145-1148<br/>

http://publicationslist.org/cornelia.denz/refid97 2012-01-03T12:31:15Z

We study the mutual trapping of two dipole-mode light beams in a medium with a nonlocal anisotropic saturable nonlinearity. It is shown that the incoherent attraction of perpendicularly aligned dipole-mode beams leads to the stabilization of their composite structure. Our numerical analysis gives a stationary solution that is stable only with respect to small amplitude modulations. The coupled sol...<br/><br/>M Ahles, K Motzek, A Stepken, F Kaiser, C Weilnau, C Denz (2002) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 19: 3 557-562<br/>

http://publicationslist.org/cornelia.denz/refid96 2012-01-03T12:31:15Z

We study (2 + 1)-dimensional multicomponent spatial vector solitons with a nontrivial topological structure of their constituents and demonstrate that these solitary waves exhibit a symmetry-breaking instability, provided their total topological charge is nonzero. We describe a novel type of stable multicomponent dipole-mode solitons with intriguing swinging dynamics. (C) 2002 Optical Society of A...<br/><br/>A S Desyatnikov, Y S Kivshar, K Motzek, F Kaiser, C Weilnau, C Denz (2002) <i>OPTICS LETTERS</i> <i></i> <i></i> 27: 8 634-636<br/>

http://publicationslist.org/cornelia.denz/refid94 2012-01-03T12:31:15Z

We study the existence and stability of multi-component spatial optical solitons in anisotropic nonlocal photorefractive media. For the case of three components, we find numerically the whole family of composite solitons with two perpendicular dipole components, and show their stability for a wide range of parameters. We confirm our theoretical results by an experimental observation of these novel...<br/><br/>K Motzek, F Kaiser, C Weilnau, C Denz, G McCarthy, W Krolikowski, A Desyatnikov, Y S Kivshar (2002) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 209: 4-6 501-506<br/>

http://publicationslist.org/cornelia.denz/refid95 2012-01-03T12:31:15Z

We present theoretical and experimental investigations of the anisotropic character of the refractive-index modulation that is induced by a light beam propagating in a photorefractive strontium barium niobate crystal. Such a structure creates a so-called spatial screening soliton that is able to carry a second wave of a different wavelength and therefore can act as a waveguide. We show in numerica...<br/><br/>J Petter, C Denz, A Stepken, F Kaiser (2002) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 19: 5 1145-1149<br/>

http://publicationslist.org/cornelia.denz/refid93 2012-01-03T12:31:15Z

(2+1)-dimensional optical spatial solitons have become a major field of research in nonlinear physics throughout the last decade due to their potential in adaptive optical communication technologies. With the help of photorefractive crystals that supply the required type of nonlinearity for soliton generation, we are able to demonstrate experimentally the formation, the dynamic properties, and esp...<br/><br/>C Weilnau, M Ahles, J Petter, D Trager, J Schroder, C Denz (2002) <i>ANNALEN DER PHYSIK</i> <i></i> <i></i> 11: 8 573-629<br/>

http://publicationslist.org/cornelia.denz/refid105 2012-01-03T12:31:15Z

Experimental and theoretical studies of the photovoltaic shift in the position of the diffraction efficiency maximum of holograms recorded in LiNbO3 for the case of optimal electric field multiplexing are described. The experimental data are explained using a model in which the bulk photovoltaic field is excited in a crystal that is electrically connected with a low loading resistance. We suggest ...<br/><br/>V M Petrov, C Denz, A V Chamray, M P Petrov, T Tschudi (2001) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 72: 6 701-705<br/>

http://publicationslist.org/cornelia.denz/refid104 2012-01-03T12:31:15Z

We report experimental observations of the mode dynamics in a weakly multimode photorefractive ring oscillator with induced astigmatism. First a gallery of transverse, higher-order Gaussian modes in the system is presented. Subsequently the dynamics of beating modes and the interactions between modes belonging to different bases are examined. The latter show the transition of modes between the thr...<br/><br/>S J Jensen, R Nicolaus, C Denz (2001) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 18: 7 966-973<br/>

http://publicationslist.org/cornelia.denz/refid108 2012-01-03T12:31:15Z

In this paper we show the guidance of a HeNe probe beam in photorefractive (2+1)D-solitons created by a beam of a frequency-doubled Nd:YAG laser in SBN. In the first part the development of a single soliton is shown in a time-resolved manner while the guided probe beam is found to follow exactly the movement of the soliton and even copies its shape. In the second part the guidance of a probe beam ...<br/><br/>J Petter, C Denz (2001) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 188: 1-4 55-61<br/>

http://publicationslist.org/cornelia.denz/refid103 2012-01-03T12:31:15Z

Stable dipole-mode vector solitons in photorefractive (PR) crystals are studied, both in numerical simulations and in experimental investigation. Numerically exact multi-humped solitary solutions to the propagation equations of two incoherently coupled beams in PR media with an anisotropic nonlocal material response are found. A continuous set of dipole-mode vector solitons, ranging from the solit...<br/><br/>K Motzek, A Stepken, F Kaiser, M R Belic, M Ahles, C Weilnau, C Denz (2001) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 197: 1-3 161-167<br/>

http://publicationslist.org/cornelia.denz/refid106 2012-01-03T12:31:15Z

We review the generation of the recently predicted multi-component spatial optical solitons in a saturable nonlinear bulk medium. We present numerical simulations for an effectively isotropic model and experimental results for a set of different combinations of a Gaussian beam co-propagating incoherently with a beam of a more complex internal structure, such as a higher order transverse laser mode...<br/><br/>C Weilnau, W Krolikowski, E A Ostrovskaya, M Ahles, M Geisser, G McCarthy, C Denz, Y S Kivshar, B Luther-Davies (2001) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 72: 6 723-727<br/>

http://publicationslist.org/cornelia.denz/refid107 2012-01-03T12:31:15Z

We report theoretical and experimental evidence for transverse modulational instability of two counterpropagating beams in a photorefractive medium with no external feedback. A frequency detuning is applied to one of the beams in order to drive the system to instability. We perform a linear-stability analysis that allows for detuning of the counterpropagating pump beams in addition to an additiona...<br/><br/>M Schwab, C Denz, M Saffman (2001) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 18: 5 628-638<br/>

http://publicationslist.org/cornelia.denz/refid99 2012-01-03T12:31:15Z

We present two different techniques on how to realize a content-addressed holographic memory when using phase-code multiplexing, relying on simple intensity measurements rather than phase distributions. Theoretical and experimental results of associative recall in a phase-coded system designed for digital data storage will be presented and compared to the corresponding method when using angular mu...<br/><br/>G Berger, C Denz, S S Orlov, B Phillips, L Hesselink (2001) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 73: 8 839-845<br/>

http://publicationslist.org/cornelia.denz/refid102 2012-01-03T12:31:15Z

We demonstrate the equivalence of the electric field and spectral multiplexing (SM) technique for holographic recording in photorefractive materials. The proposed technique of electric field multiplexing (EFM) provides a spectral selectivity of recorded holographic filters up to a few picometers. (C) 2001 Elsevier Science B.V. All rights reserved.<br/><br/>V M Petrov, C Denz, A V Shamray, M P Petrov, T Tschudi (2001) <i>OPTICAL MATERIALS</i> <i></i> <i></i> 18: 1 191-194<br/>

http://publicationslist.org/cornelia.denz/refid100 2012-01-03T12:31:15Z

We investigate the generation of higher-order optical vector solitons in two transverse dimensions in anisotropic nonlinear media consisting of an incoherent superposition of a Gaussian beam and a higher-order laser mode with a complex internal modal structure. We demonstrate both numerically and experimentally various examples of these stable self-trapped light structures and show that vortex mod...<br/><br/>C Weilnau, C Denz, M Ahles, A Stepken, K Motzek, F Kaiser (2001) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 64: 5, Part 2 <br/>

http://publicationslist.org/cornelia.denz/refid101 2012-01-03T12:31:15Z

We show that manipulation and selection of optical patterns is possible by detuning the frequency of one of the two waves in counterpropagating photorefractive two-wave mixing with a feedback mirror. An analytical expression for the onset of modulational instability is derived for the general case of an arbitrary complex coupling constant, including a possible frequency shift of the generated side...<br/><br/>M Schwab, C Denz, A V Mamaev, M Saffman (2001) <i>JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 3: 5 318-327<br/>

http://publicationslist.org/cornelia.denz/refid111 2012-01-03T12:31:15Z

The photorefractive properties of Bi2TeO5 crystals were measured with the wave mixing technique using the 532 nm output of a Nd:YAG laser for writing gratings. The saturation diffraction efficiency of the grating for the optimum crystal orientation and beam polarization configuration exceeded the 40%. Above a threshold write intensity, a remarkable fraction (10-20%) of the saturation diffraction e...<br/><br/>I Foldvari, C Denz, A Peter, J Petter, F Visinka (2000) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 177: 1-6 105-109<br/>

http://publicationslist.org/cornelia.denz/refid110 2012-01-03T12:31:15Z

Theoretical and experimental investigations of electric field multiplexing and selectivity of reflection volume holograms in LiNbO3 are reported. Recording of at least five holograms is demonstrated. Equivalent spectral selectivity Delta lambda approximate to 4.5 pm for the case of three electrically tunable holograms and Delta lambda approximate to 9 pm for the case of five electrically tunable h...<br/><br/>V M Petrov, C Denz, A V Shamray, M P Petrov, T Tschudi (2000) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 71: 1 43-46<br/>

http://publicationslist.org/cornelia.denz/refid109 2012-01-03T12:31:15Z

We report on the first experimental observation of a novel type of optical vector soliton, a dipole-mode soliton, recently predicted theoretically. We show that these vector solitons can be generated in a photorefractive medium employing two different processes: a phase imprinting, and a symmetry-breaking instability of a vortex-mode vector soliton. The experimental results display remarkable agre...<br/><br/>W Krolikowski, E A Ostrovskaya, C Weilnau, M Geisser, G McCarthy, Y S Kivshar, C Denz, B Luther-Davies (2000) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 85: 7 1424-1427<br/>

http://publicationslist.org/cornelia.denz/refid118 2012-01-03T12:31:15Z

We investigate the origin of dynamics of hexagonal pattern formation in a photorefractive single feedback system. By introducing an asymmetry, we induced different complex motion behaviour. A visualization method is presented and means to control the dynamics in the case of fixed external parameters are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.<br/><br/>M Schwab, M Sedlatschek, B Thuring, C Denz, T Tschudi (1999) <i>CHAOS SOLITONS & FRACTALS</i> <i></i> <i></i> 10: 4-5 701-707<br/>

http://publicationslist.org/cornelia.denz/refid119 2012-01-03T12:31:15Z

We report results on unidirectional oscillation in a photorefractive oscillator implemented with BaTiO3 that is actively stabilized. Dynamic spatial patterns and pattern competition were observed, depending strongly on the Fresnel number of the system. As the origin for spontaneous pattern alternation we identified variations in the cavity length that are in turn mainly due to temperature fluctuat...<br/><br/>G Balzer, C Denz, O Knaup, T Tschudi (1999) <i>CHAOS SOLITONS & FRACTALS</i> <i></i> <i></i> 10: 4-5 725-730<br/>

http://publicationslist.org/cornelia.denz/refid120 2012-01-03T12:31:15Z

Phase codes of Talbot array illumination, originally derived from Talbot effect for array illumination at fractional Talbot distance, are now suggested as a set of orthogonal phase codes for phase-encoded holographic multiplexing storage in volume-holographic media. The most attractive feature of the Talbot encoding method is that an arbitrary number of images can be phase-encoded while the previo...<br/><br/>C H Zhou, S Stankovic, C Denz, T Tschudi (1999) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 161: 4-6 209-211<br/>

http://publicationslist.org/cornelia.denz/refid121 2012-01-03T12:31:15Z

We present an experimental realization of an almost non-invasive stabilization and manipulation method of coexisting and unstable states of pattern forming systems. In a photorefractive single feedback system, a control path;is:used to realize amplitude and phase-sensitive Fourier-plane filtering, utilizing only a few per cent of the system’s intensity. By that means, we were able to stabilize d...<br/><br/>C Denz, S J Jensen, M Schwab, T Tschudi (1999) <i>JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 1: 1 114-120<br/>

http://publicationslist.org/cornelia.denz/refid117 2012-01-03T12:31:15Z

We present a review of our recent theoretical and experimental results on the interaction of incoherent two-dimensional solitary beams in PR SBN crystals. We show that the inherent anisotropy of PR nonlinearity strongly affects the interaction between solitons. Theoretical and experimental results reveal that solitons interacting in a plane perpendicular to the direction of external biasing field ...<br/><br/>W Krolikowski, B Luther-Davies, C Denz, J Petter, C Weilnau, A Stepken, M Belic (1999) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 68: 5 975-982<br/>

http://publicationslist.org/cornelia.denz/refid113 2012-01-03T12:31:15Z

An experimental and numerical investigation of the dynamical, time-dependent effects accompanying the Formation and interaction of two-dimensional spatial screening solitons in a photorefractive strontium barium niobate crystal is performed. These effects include initial diffraction, collapse to the soliton shape, the oscillation of beam diameters, beam bending, and the rotation, twisting, and tur...<br/><br/>C Denz, W Krolikowski, J Petter, C Weilnau, T Tschudi, M R Belic, F Kaiser, A Stepken (1999) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 60: 5, Part b 6222-6225<br/>

http://publicationslist.org/cornelia.denz/refid112 2012-01-03T12:31:15Z

We report on the observation of a multiple-pattern stability region in a photorefractive single-feedback system. Whereas hexagonal patterns are predominant for feedback with positive diffraction length we show that a variety of stable non-hexagonal patterns are generated for certain negative diffraction lengths. For the same values of the control parameters square, rectangular, or squeezed hexagon...<br/><br/>M Schwab, C Denz, M Saffman (1999) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 69: 5-6 429-433<br/>

http://publicationslist.org/cornelia.denz/refid116 2012-01-03T12:31:15Z

In this article, we demonstrate the capability of a two-beam coupling photorefractive optical novelty filter of detecting changes in the amplitude or phase of optical images. These changes may either be continuous or discrete in time. The performance of the two-beam coupling novelty filter is investigated and expressions for the output contrast corresponding to phase and amplitude changes based on...<br/><br/>M Sedlatschek, J Trumpfheller, J Hartmann, M Muller, C Denz, T Tschudi (1999) <i>APPLIED PHYSICS B-LASERS AND OPTICS</i> <i></i> <i></i> 68: 5 1047-1054<br/>

http://publicationslist.org/cornelia.denz/refid114 2012-01-03T12:31:15Z

Self-bending of photorefractive solitons is caused by diffusion in photorefractive crystals and becomes an important effect when the beam size is in the range of the charge carriers diffusion length. In this paper we present an experimental and numerical examination of the beam bending dependence on relevant parameters such as the applied electric field and the beam intensity. We demonstrate that ...<br/><br/>J Petter, C Weilnau, C Denz, A Stepken, F Kaiser (1999) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 170: 4-6 291-297<br/>

http://publicationslist.org/cornelia.denz/refid115 2012-01-03T12:31:15Z

We present a control method for the minimally invasive manipulation of pattern states occurring in feedback systems with an optical nonlinearity. An interferometric feedback configuration is used to control spontaneously formed patterns by the method of Fourier filtering. This method is minimally invasive since the pattern forming feedback arm remains unchanged, while the energy removed by the fil...<br/><br/>M Schwab, M Saffman, C Denz, T Tschudi (1999) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 170: 1-3 129-136<br/>

http://publicationslist.org/cornelia.denz/refid127 2012-01-03T12:31:15Z

We investigate experimentally the interaction of two-dimensional solitary beams in photorefractive strontium barium niobate crystal. We show that simultaneous collision of many solitons can result in complete annihilation of some of them. This effect depends on the relative phases of the solitons and may be useful for application in the formation of multiport waveguide junctions. (C) 1998 Optical ...<br/><br/>W Krolikowski, B Luther-Davies, C Denz, T Tschudi (1998) <i>OPTICS LETTERS</i> <i></i> <i></i> 23: 2 97-99<br/>

http://publicationslist.org/cornelia.denz/refid125 2012-01-03T12:31:15Z

We investigate the temporal dynamics of transverse optical patterns spontaneously formed in a photorefractive single-feedback system with a virtual feedback mirror. The linear stability analysis for the system is reviewed and extended to the region of larger propagation lengths. The stationary patterns obtained experimentally are classified as a function of feedback reflectivity and feedback mirro...<br/><br/>C Denz, M Schwab, M Sedlatschek, T Tschudi, T Honda (1998) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 15: 7 2057-2064<br/>

http://publicationslist.org/cornelia.denz/refid126 2012-01-03T12:31:15Z

We investigate the interaction of mutually incoherent spatial solitons in photorefractive media with anisotropic nonlocal nonlinear response. We show that the photorefractive nonlinearity leads to an anomalous interaction between solitons. Theoretical and experimental results reveal that an incoherent soliton pair may experience both attractive and repulsive forces, depending on their mutual separ...<br/><br/>W Krolikowski, M Saffman, B Luther-Davies, C Denz (1998) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 80: 15 3240-3243<br/>

http://publicationslist.org/cornelia.denz/refid123 2012-01-03T12:31:15Z

We present the design and realization of a compact volume holographic memory based on phase-coded multiplexing. Due to the use of nonmechanical reference beam changes in this multiplexing technique, rapid access of the stored data pages is achieved. Our system can reach a maximum storage capacity up to 480 data pages with a resolution of 640 x 480 pixels in a single interaction region of a photore...<br/><br/>C Denz, K O Muller, T Heimann, T Tschudi (1998) <i>IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS</i> <i></i> <i></i> 4: 5 832-839<br/>

http://publicationslist.org/cornelia.denz/refid124 2012-01-03T12:31:15Z

We present an experimental realization of an almost noninvasive stabilization and manipulation method of coexisting and underlying states of pattern forming systems. In a photorefractive single feedback system, a ring control path is used to realize amplitude and phase-sensitive Fourier-plane filtering, utilizing only a few percent of the system’s intensity. We were able to stabilize desired but...<br/><br/>S J Jensen, M Schwab, C Denz (1998) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 81: 8 1614-1617<br/>

http://publicationslist.org/cornelia.denz/refid122 2012-01-03T12:31:15Z

We present a review of our recent theoretical and experimental results on the interaction of two-dimensional solitary beams in photorefractive SBN crystals. We show that the collision of coherent solitons may result in energy exchange, fusion of the interacting solitons, the birth of a new solitary beam or the complete annihilation of some of them, depending on the relative phase of the interactin...<br/><br/>W Krolikowski, C Denz, A Stepken, M Saffman, B Luther-Davies (1998) <i>QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 10: 6 823-837<br/>

http://publicationslist.org/cornelia.denz/refid129 2012-01-03T12:31:15Z

Spontaneous formation of optical patterns is studied in a system composed of a photorefractive phase-conjugating medium and a virtually internal feedback minor, In addition to ordinary regular hexagons, squares and squeezed hexagons are reported for the first time in optical pattern formation experiments, The angle of the generated sideband beams plotted as a function of the mirror position lies o...<br/><br/>T Honda, H Matsumoto, M Sedlatschek, C Denz, T Tschudi (1997) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 133: 1-6 293-299<br/>

http://publicationslist.org/cornelia.denz/refid128 2012-01-03T12:31:15Z

The signal-to-noise ratio of the output of an adaptive holographic interferometer (AHI) based on a Bi12TiO20 crystal is investigated. We show experimentally that the sensitivity of an AHI using the non-Bragg orders of diffraction in a thin photoreactive material is more than an order of magnitude greater than that of an AHI employing two-wave mixing in photorefractive volume holograms. (C) 1997 Op...<br/><br/>V Petrov, C Denz, J Petter, T Tschudi (1997) <i>OPTICS LETTERS</i> <i></i> <i></i> 22: 24 1902-1904<br/>

http://publicationslist.org/cornelia.denz/refid130 2012-01-03T12:31:15Z

We propose and demonstrate experimentally a method for utilizing a dynamic phase-encoded photorefractive memory to realize parallel optical addition, subtraction, and inversion operations of stored images. The phase-encoded holographic memory is realized in photorefractive BaTiO3, storing eight images using Walsh-Hadamard binary phase codes and an incremental recording procedure. By subsampling th...<br/><br/>C Denz, T Dellwig, J Lembcke, T Tschudi (1996) <i>OPTICS LETTERS</i> <i></i> <i></i> 21: 4 278-280<br/>

http://publicationslist.org/cornelia.denz/refid134 2012-01-03T12:31:15Z

We present the design, implementation and detailed investigations on the characteristics of an optical novelty filter based on two-wave mixing in photorefractive BaTiO3. The system is cabable on novelty filtering two-dimensional video images using a commercially available liquid crystal display. The setup was realized as a compact demonstrator device. A contrast of up to 40:1 and a limiting freque...<br/><br/>M SEDLATSCHEK, T RAUCH, C DENZ, T TSCHUDI (1995) <i>OPTICAL MATERIALS</i> <i></i> <i></i> 4: 2-3 376-380<br/>

http://publicationslist.org/cornelia.denz/refid135 2012-01-03T12:31:15Z

A general formalism for multiplexed holographic image storage is described which includes both phase and angular encoding techniques. A combination of both methods can easily be treated as well. We derive an expression for the spatial modulation of the refractive index after storage of all images, calculate the diffraction amplitude during readout and deduce the conditions for selective readout. F...<br/><br/>J LEMBCKE, C DENZ, T TSCHUDI (1995) <i>OPTICAL MATERIALS</i> <i></i> <i></i> 4: 2-3 428-432<br/>

http://publicationslist.org/cornelia.denz/refid133 2012-01-03T12:31:15Z

A numerical method to simulate the photorefractive phase conjugation process in rather general conditions, pump depletion and multigrating operation, has been developed. Previous theoretical works had been essentially devoted to study the steady state situation. With this numerical calculation we can analyze the time evolution of the phase conjugate beam when all gratings are operative. The respon...<br/><br/>M DELPINO, T RAUCH, C DENZ, M CARRASCOSA (1995) <i>OPTICAL MATERIALS</i> <i></i> <i></i> 4: 2-3 326-329<br/>

http://publicationslist.org/cornelia.denz/refid132 2012-01-03T12:31:15Z

A general theory of the resolution of arbitrary novelty filters, optical as well as electronic, including the only existing theory as a special case, is presented. Resolution is calculated for the two essential processes of object tracking, i.e. object localization and separation of different objects. Algorithms for the reconstruction of the original objects from the output image are developed. Co...<br/><br/>M SEDLATSCHEK, T RAUCH, C DENZ, T TSCHUDI (1995) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 116: 1-3 25-30<br/>

http://publicationslist.org/cornelia.denz/refid131 2012-01-03T12:31:15Z

We propose and demonstrate experimentally a new, phase-locked refreshment method for reading out dynamic holographic photorefractive memories without destruction of the stored information. This refreshment method can be used for various multiplexing techniques as angular-, phase encoded- or wavelength multiplexing and for different recording schedules as sequential or incremental recording. In a f...<br/><br/>T DELLWIG, C DENZ, T RAUCH, T TSCHUDI (1995) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 119: 3-4 333-340<br/>

http://publicationslist.org/cornelia.denz/refid136 2012-01-03T12:31:15Z

The advantages and limitations of data storage in holographic materials by implementing a pure phase-encoding method of the reference beam are studied. We show that if deterministic orthogonal binary phase addresses are used, such a system is theoretically able to store as many images as the usual angular multiplexing method. However, we demonstrate that imperfections of available optical componen...<br/><br/>C DENZ, G PAULIAT, G ROOSEN, T TSCHUDI (1992) <i>APPLIED OPTICS</i> <i></i> <i></i> 31: 26 5700-5705<br/>

http://publicationslist.org/cornelia.denz/refid137 2012-01-03T12:31:15Z

The self-pumped BaTiO3 phase-conjugate mirror (SPPCM) is presented as a nonlinear system that exhibits temporal irregular fluctuations in the phase-conjugated output in dependence on one critical parameter - the beam input position. Qualitative examinations of the nature of these fluctuations, the Fourier transform, the autocorrelation function and the Poincare map, show signs of deterministic cha...<br/><br/>T RAUCH, C DENZ, T TSCHUDI (1992) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 88: 2-3 160-166<br/>

http://publicationslist.org/cornelia.denz/refid138 2012-01-03T12:31:15Z

We present a novel phase encoding method for high capacity optical data storage in volume photorefractive materials. Using deterministic orthogonal phase codes in a reference-based multiplexing technique, we obtain a system that is able to retrieve multiple images with high diffraction efficiency without energy losses, adjustment problems or any time delay. The number of images which can be stored...<br/><br/>C DENZ, G PAULIAT, G ROOSEN, T TSCHUDI (1991) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 85: 2-3 171-176<br/>

http://publicationslist.org/cornelia.denz/refid139 2012-01-03T12:31:15Z

L KLEES, C DENZ, T TSCHUDI (1990) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 77: 1 65-70<br/>

http://publicationslist.org/cornelia.denz/refid140 2012-01-03T12:31:15Z

C DENZ, J GOLTZ, T TSCHUDI (1989) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 72: 1-2 129-134<br/>

http://publicationslist.org/cornelia.denz/refid142 2012-01-03T12:31:15Z

J GOLTZ, C DENZ, T TSCHUDI (1988) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 68: 3 228-230<br/>

http://publicationslist.org/cornelia.denz/refid141 2012-01-03T12:31:15Z

J GOLTZ, C DENZ, T TSCHUDI (1988) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 68: 6 453-456<br/>

http://publicationslist.org/cornelia.denz/refid143 2012-01-03T12:31:15Z

J GOLTZ, C DENZ, H KLUMB, T TSCHUDI, J ALBERS (1988) <i>OPTICS LETTERS</i> <i></i> <i></i> 13: 4 321-323<br/>