http://publicationslist.org/data/kenju.otsuka/atom.xml Kenju Otsukahttp://publicationslist.org/kenju.otsuka$basepathfavicon.icoRecent additions to Kenju Otsuka's PublicationsList.org pagehttp://publicationslist.org/publications.png2009-11-20T07:57:34Z http://publicationslist.org/kenju.otsuka/refid6 2009-11-11T05:38:29Z

We demonstrate vortex array-beam generations from a thin-slice, wide-aperture, solid-state laser with laser-diode end-pumping. Radial and rectangular vortex arrays were found to be formed in a controlled fashion with symmetric and asymmetric pump-beam profiles, respectively. Most of these vortices exhibited single-frequency oscillations arising from a spontaneous process of transverse mode locking...<br/><br/>K Otsuka, S C Chu (2009) <i>OPTICS LETTERS</i> <i></i> <i></i> 34: 1 10-12<br/>

http://publicationslist.org/kenju.otsuka/refid112 2009-11-12T05:40:41Z

K. Otsuka, S C Chu, C C Lin, K. Tokunaga and T. Ohtomo (2009) <i>OPTICS EXPRESS </i> 17: 21615-21617 <br/>

http://publicationslist.org/kenju.otsuka/refid5 2009-11-11T05:38:29Z

We report successful real-time three-channel self-mixing laser-Doppler measurements with extreme optical sensitivity using a laser-diode-pumped thin-slice Nd:GdVO4 laser in the carrier-frequency-division-multiplexing scheme with three pairs of acoustic optical modulators (i.e., frequency shifters) and a three-channel FM-wave demodulation circuit. We demonstrate (1) simultaneous independent measure...<br/><br/>T Ohtomo, S Sudo, K Otsuka (2009) <i>APPLIED OPTICS</i> <i></i> <i></i> 48: 3 609-616<br/>

http://publicationslist.org/kenju.otsuka/refid4 2009-11-11T05:38:29Z

The overall dynamics of Brownian particles suspended in water were captured with high time resolution by using a self-mixing thin-slice solid-state laser. The net motion of an ensemble of many particles moving in the small imaging field observed at given time intervals was found to be represented by Brownian motions of an effective medium obeying the Ornstein-Uhlenbeck process, whose physical para...<br/><br/>K Otsuka, T Ohtomo, H Makino, S Sudo, J Y Ko (2009) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 94: 24 <br/>

http://publicationslist.org/kenju.otsuka/refid1 2009-11-11T05:38:29Z

Mathieu-Gauss mode oscillations were observed in micro-grained isotropic Nd:YAG microchip ceramic lasers with azimuth laser diode pumping. The effect of fluorescence anisotropy thermal birefringence on these patter formations is discussed for several laser materials.<br/><br/>K Tokunaga, S C Chu, H Y Hsiao, T Ohtomo, K Otsuka (2009) <i>LASER PHYSICS LETTERS</i> <i></i> <i></i> 6: 9 635-638<br/>

http://publicationslist.org/kenju.otsuka/refid2 2009-11-11T05:38:29Z

We present an analysis of the shoulder-shaped power spectrum observed in the modulated laser output due to feedback light scattered from dynamic changes in self-mobile phytoplankton with flagella in seawater performed using a self-mixing laser Doppler vibrometry system. The power spectrum occasionally has shoulder-shaped broad frequency components superimposed on a Lorentz-type spectrum. This refl...<br/><br/>S Sudo, T Ohtomo, Y Takahashi, T Oishi, K Otsuka (2009) <i>APPLIED OPTICS</i> <i></i> <i></i> 48: 20 4049-4055<br/>

http://publicationslist.org/kenju.otsuka/refid3 2009-11-11T05:38:29Z

We have demonstrated self-mixing laser Doppler measurements using a laser-diode-pumped thin-slice Yb:Y3Al5O12 (Yb:YAG) ceramic laser whose optical sensitivity is two orders of magnitude higher than that of Nd-doped solid-state lasers, e.g., Nd:GdVO4. The pronounced optical sensitivity has been experimentally and theoretically shown to result from a longer fluorescence lifetime inherent in Yb atoms...<br/><br/>T Ohtomo, K Otsuka (2009) <i>JAPANESE JOURNAL OF APPLIED PHYSICS</i> <i></i> <i></i> 48: 7 <br/>

http://publicationslist.org/kenju.otsuka/refid12 2009-11-11T05:38:29Z

An apparatus to achieve a single doughnut-like Laguerre-Gaussian (LG) mode with extremely high mode purity higher than 99.6% is reported. The proposed apparatus is a conceptual combination of a high-order HG mode selector and an astigmatic mode converter, which consists of only four simple and easily-made optical elements: three lens elements and one binary phase element. Theoretical simulations s...<br/><br/>S C Chu, K Otsuka (2008) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 281: 6 1647-1653<br/>

http://publicationslist.org/kenju.otsuka/refid10 2009-11-11T05:38:29Z

We report selective excitations of higher-order Hermite-Gaussian and Ince-Gaussian (IG) modes in a laser-diode-pumped microchip solid-state laser and controlled generation of corresponding higher-order and multiple optical vortex beams of different shapes using an astigmatic mode converter (AMC). Simply changing the pump-beam diameter, shape, and lateral off-axis position of the tight pump beam fo...<br/><br/>T Ohtomo, S C Chu, K Otsuka (2008) <i>OPTICS EXPRESS</i> <i></i> <i></i> 16: 7 5082-5094<br/>

http://publicationslist.org/kenju.otsuka/refid7 2009-11-11T05:38:29Z

This paper proposes a new scheme for generating vortex laser beams from a laser. The proposed system consists of a Dove prism embedded in an unbalanced Mach-Zehnder interferometer configuration. This configuration allows controlled construction of p x p vortex array beams from Ince-Gaussian modes, IG(p,p)(e) modes. An incident IG(p,p)(e) laser beam of variety order p can easily be generated from a...<br/><br/>S C Chu, C S Yang, K Otsuka (2008) <i>OPTICS EXPRESS</i> <i></i> <i></i> 16: 24 19934-19949<br/>

http://publicationslist.org/kenju.otsuka/refid9 2009-11-11T05:38:29Z

This study demonstrates successive higher-order Hermite-Gaussian (HG(0,m)) mode operations in a microchip solid-state laser with a controlled off-axis laser diode (LD) pumping and generation of the corresponding doughnutlike laser beam of tunable ring diameter and orbital angular momentum, by experimentally focusing a Hermite-Gaussian mode (HGM) lasing beam into an astigmatic mode converter (AMC) ...<br/><br/>S C Chu, T Ohtomo, K Otsuka (2008) <i>APPLIED OPTICS</i> <i></i> <i></i> 47: 14 2583-2591<br/>

http://publicationslist.org/kenju.otsuka/refid8 2009-11-11T05:38:29Z

Detailed polarization properties have been examined in laser-diode-pumped (LD-pumped) micro-grained ceramic Nd:YAG lasers in different microchip cavity configurations. Stable linearly-polarized single-frequency oscillations, whose polarization direction coincides with that of an LD pump light, were observed in an external cavity scheme. In the case of a thin-slice laser scheme with coated reflecti...<br/><br/>K Otsuka, T Ohtomo (2008) <i>LASER PHYSICS LETTERS</i> <i></i> <i></i> 5: 9 659-663<br/>

http://publicationslist.org/kenju.otsuka/refid18 2009-11-11T05:38:29Z

We report on the experimental observations of chaos synchronizations among orthogonally polarized emissions in a dual-polarization laser. With a three-mode scheme with a single mode in one polarization and two modes in orthogonal polarizations, synchronization was achieved by the cross-saturation dynamics of population inversions when one of the dual-polarized emissions was subjected to external p...<br/><br/>K Otsuka, K Nemoto, K Kamikariya, Y Miyasaka, J Y Ko, C C Lin (2007) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 76: 2 <br/>

http://publicationslist.org/kenju.otsuka/refid19 2009-11-11T05:38:29Z

We observed self-formation of looped random lasing paths in a laser-diode-pumped wide-aperture thin-slice solid-state laser with imperfect reflective end surfaces. Observed lasing patterns, resulting from random scatterers on the surfaces, showed transverse intensity distributions possessing exponential spatial autocorrelation functions. It is shown that such a speckle type of lasing pattern forma...<br/><br/>K Otsuka, Y Miyasaka, K Nemoto (2007) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 75: 6 <br/>

http://publicationslist.org/kenju.otsuka/refid17 2009-11-11T05:38:29Z

We describe a highly sensitive, real-time method of detecting small particles in a fluid flow by self-mixing laser Doppler measurement with a laser-diode-pumped, thin-slice solid-state laser with extremely high optical sensitivity. Asymmetric power spectra of the laser output modulated by the re-injected scattered light from the small particles moving in a dilute sample-flow, through a small-diame...<br/><br/>S Sudo, Y Miyasaka, K Nemoto, K Kamikariya, K Otsuka (2007) <i>OPTICS EXPRESS</i> <i></i> <i></i> 15: 13 8135-8145<br/>

http://publicationslist.org/kenju.otsuka/refid22 2009-11-11T05:38:29Z

Dual-polarization oscillations (DPO) on different transitions have been observed for the first time in a mirror-coated thin-slice Nd:GdVO4 laser possessing a large fluorescence anisotropy with laser-diode (LD) pumping. Oscillation spectra, input-output characteristics, pump-dependent pattern formations and noise power spectra are studied experimentally. Simultaneous oscillations of orthogonally-po...<br/><br/>J Y Ko, C C Lin, K Otsuka, Y Miyasaka, K Kamikariya, K Nemoto, M C Ho, I M Jiang (2007) <i>OPTICS EXPRESS</i> <i></i> <i></i> 15: 3 945-954<br/>

http://publicationslist.org/kenju.otsuka/refid13 2009-11-11T05:38:29Z

This study proposes a three-lens configuration for generating a stable donutlike vortex laser beam with controlled Ince-Gaussian mode (IGM) operation in the model of laser-diode (LD)-pumped solid-state lasers. Simply controlling the lateral off-axis position of the pump beam's focus on the laser crystal can generate a desired donutlike vortex beam from the proposed simple and easily made three-len...<br/><br/>S C Chu, K Otsuka (2007) <i>APPLIED OPTICS</i> <i></i> <i></i> 46: 31 7709-7719<br/>

http://publicationslist.org/kenju.otsuka/refid16 2009-11-11T05:38:29Z

Various single-frequency Ince-Gaussian mode oscillations have been achieved in laser-diode-pumped microchip solid- state lasers, including LiNdP4O12 (LNP) and Nd: GdVO4, by adjusting the azimuthal symmetry of the short laser resonator. Ince-Gaussian modes formed by astigmatic pumping have been reproduced by numerical simulation.<br/><br/>T Ohtomo, K Kamikariya, K Otsuka, S C Chu (2007) <i>OPTICS EXPRESS</i> <i></i> <i></i> 15: 17 10705-10717<br/>

http://publicationslist.org/kenju.otsuka/refid14 2009-11-11T05:38:29Z

The effect of average grain size on oscillation properties is studied in laser-diode-pumped miniature ceramic lasers. The inherent segregation of lasing patterns into local modes is found to be prevented in the case of ceramics with grains of micrometer size, resulting in linearly polarized TEM00 transverse-mode oscillations.<br/><br/>T Ohtomo, K Kamikariya, K Otsuka (2007) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS</i> <i></i> <i></i> 46: 41-44 L1013-L1015<br/>

http://publicationslist.org/kenju.otsuka/refid15 2009-11-11T05:38:29Z

Detailed oscillation spectra and polarization properties have been examined in laser-diode-pumped (LD-pumped) microchip ceramic (i.e., polycrystalline) Nd:NAG lasers and the inherent segregation of lasing patterns into local modes possessing different polarization states was observed. Single-frequency linearly-polarized stable oscillations were realized by forcing the laser to Ince-Gaussian mode o...<br/><br/>K Otsuka, K Nemoto, K Kamikariya, Y Miyasaka, S C Chu (2007) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS</i> <i></i> <i></i> 46: 9A 5865-5867<br/>

http://publicationslist.org/kenju.otsuka/refid28 2009-11-11T05:38:29Z

We describe a method for quickly and easily measuring the size of small particles in suspensions. This method uses a self-mixing laser Doppler measurement with a laser-diode-pumped, thin-slice LiNdP4O12 laser with extremely high optical sensitivity. The average size of the particles in Brownian motion is determined by a Lorentz fitting of the measured power spectrum of the modulated self-mixing la...<br/><br/>S Sudo, Y Miyasaka, K Otsuka (2006) <i>OPTICS EXPRESS</i> <i></i> <i></i> 14: 3 1044-1054<br/>

http://publicationslist.org/kenju.otsuka/refid26 2009-11-11T05:38:29Z

The authors propose a coupled spatially distributed local-mode laser model for understanding self-induced high-speed modulations in Nd:YAG ceramic lasers with laser-diode end pumping, which critically depend on pump positions. In addition to complicated high-speed modulations, quasiperiodic and chaotic relaxation oscillations have been demonstrated experimentally and reproduced by numerical simula...<br/><br/>K Otsuka, T Narita, Y Miyasaka, C C Lin, J Y Ko, S C Chu (2006) <i>APPLIED PHYSICS LETTERS</i> <i></i> <i></i> 89: 8 <br/>

http://publicationslist.org/kenju.otsuka/refid25 2009-11-11T05:38:29Z

Doppler particle sizing by self-mixing laser was demonstrated by using a laser-diode-pumped thin-slice Nd:GdVO4 laser with extreme optical sensitivity. A substantial improvement of optical frequency shifters led to quick and accurate sizing of Brownian particles with concentration as low as 50 parts per billion (ppb), for 262-nm polystyren latex spheres in water. A successful real-time measurement...<br/><br/>S Sudo, Y Miyasaka, K Kamikariya, K Nemoto, K Otsuka (2006) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS</i> <i></i> <i></i> 45: 33-36 L926-L928<br/>

http://publicationslist.org/kenju.otsuka/refid24 2009-11-11T05:38:29Z

We observed self-formations of multiple lasing channels and two-dimensional lasing patterns consisting of composite local modes having different lasing frequencies in a laser-diode-pumped wide-aperture thin-slice solid-state laser with imperfect reflective end surfaces. Global patterns resembling higher-order Hermite-Gaussian modes or possessing N-fold rotational symmetries were experimentally sho...<br/><br/>K Otsuka, Y Miyasaka, T Narita, S C Chu, C C Lin, J Y Ko (2006) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 97: 21 <br/>

http://publicationslist.org/kenju.otsuka/refid34 2009-11-11T05:38:29Z

We studied the dynamic behavior of laser-diode-pumped nonidentical thin-slice solid-state lasers, coupled face to face, with orthogonally polarized emissions. When such an incoherent mutual optical coupling was introduced, the coupled lasers exhibited slow fluctuations of transverse-mode patterns, and isolated lasers exhibited stable transverse-mode patterns. When one laser exhibited nonorthogonal...<br/><br/>T Ohtomo, Y Miyasaka, K Otsuka, A Okamoto, J Y Ko (2005) <i>OPTICS EXPRESS</i> <i></i> <i></i> 13: 2 358-370<br/>

http://publicationslist.org/kenju.otsuka/refid33 2009-11-11T05:38:29Z

We demonstrate real-time two-channel self-mixing laser-Doppler measurement with extreme optical sensitivity using a laser-diode-pumped thin-slice LiNdP4O12 laser. Successful carrier-frequency-division-multiplexed two-channel operations are realized by using one laser, two sets of optical frequency shifters, and a two-channel frequency-modulated-wave demodulation circuit. Simultaneous independent m...<br/><br/>K Otsuka, K Abe, N Sano, S Sudo, J Y Ko (2005) <i>APPLIED OPTICS</i> <i></i> <i></i> 44: 9 1709-1714<br/>

http://publicationslist.org/kenju.otsuka/refid31 2009-11-11T05:38:29Z

We systematically studied dynamic effects in Nd-doped Y3Al5O12 (YAG) ceramic lasers having different Nd concentrations. A variety of dynamic instabilities, including square wave periodic pulsations, were found to take place due to the increased grain boundaries in highly-doped samples.<br/><br/>T Narita, Y Miyasaka, K Otsuka (2005) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS</i> <i></i> <i></i> 44: 37-41 L1168-L1170<br/>

http://publicationslist.org/kenju.otsuka/refid32 2009-11-11T05:38:29Z

We found an abrupt transverse-mode transition from an irregular to a Gaussian lasing pattern or billiard-like lasing patterns with increasing the pump power in a laser-diode-pumped thin-slice Nd:GdVO4 laser with coated dielectric mirrors on both ends. A variety of irregular stationary lasing patterns were observed with a slight change in the pump position due to polished crystal surface roughness ...<br/><br/>Y Miyasaka, T Narita, K Otsuka, H Makino, A Okamoto, J Y Ko (2005) <i>OPTICS EXPRESS</i> <i></i> <i></i> 13: 20 7928-7936<br/>

http://publicationslist.org/kenju.otsuka/refid38 2009-11-11T05:38:29Z

We investigated self-induced pulsations in a globally-coupled microchip multimode solid-state laser operating on a Lambda transition. A variety of dynamic states, featuring locking of pulsation frequencies, multidimensional quasiperiodic, and chaotic pulsations, induced by nonlinear modal interactions were observed depending on the number of oscillating modes. The underlying modal interplay was ch...<br/><br/>K Otsuka, Y Miyasaka, T Kubota, J Y Ko (2004) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 69: 4 <br/>

http://publicationslist.org/kenju.otsuka/refid37 2009-11-11T05:38:29Z

This work reports on a beam quality and dynamic behaviors of a mirror-coated highly-doped YAG (Y3Al5O12) microchip ceramic laser possessing an increased number of grain boundaries. The degradation of beam quality factor in transverse patterns due to spatial inhomogeneity across the beam, multiple split-mode operations, violation of antiphase dynamics and high-speed intensity modulations due to the...<br/><br/>R Kawai, Y Miyasaka, K Otsuka, T Ohtomo, T Narita, J Y Ko, I Shoji, T Taira (2004) <i>OPTICS EXPRESS</i> <i></i> <i></i> 12: 10 2293-2302<br/>

http://publicationslist.org/kenju.otsuka/refid35 2009-11-11T05:38:29Z

We investigated chaotic dynamics in a microchip three-mode solid-state laser subjected to frequency-shifted optical feedback: When the frequency shift was tuned to harmonic frequencies of the relaxation oscillation, a bifurcation from a periodic sustained relaxation oscillation ("soft-mode") state to a chaotic spiking ("hard-mode") state via a chaotic itinerancy was observed as the feedback intens...<br/><br/>Y Miyasaka, K Otsuka, T Maniwa, J Y Ko (2004) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 70: 4 <br/>

http://publicationslist.org/kenju.otsuka/refid36 2009-11-11T05:38:29Z

This tutorial presents a detailed description of experiments, simulations, and characterizations of chaos synchronization phenomena in the model of a mutually coupled microchip solid-state laser array subjected to self-mixing feedback modulation. We demonstrate a transition to synchronized chaos by the method of 'phase squeezing' with increasing field overlap between the two lasers. This phenomeno...<br/><br/>R Kawai, J S Lih, J Y Ko, J L Chern, K Otsuka (2004) <i>JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 6: 7 R19-R32<br/>

http://publicationslist.org/kenju.otsuka/refid45 2009-11-11T05:38:29Z

Nanometre vibration measurement of an audio speaker and a highly sensitive sound reproduction experiment have been successfully demonstrated by a self-aligned optical feedback vibrometry technique using the self-mixing modulation effect in a laser-diode-pumped microchip solid-state laser. By applying nanometre vibrations to the speaker, which produced nearly inaudible music below 20 dB (200 muPa) ...<br/><br/>K Abe, K Otsuka, J Y Ko (2003) <i>NEW JOURNAL OF PHYSICS</i> <i></i> <i></i> 5: <br/>

http://publicationslist.org/kenju.otsuka/refid42 2009-11-11T05:38:29Z

Formation of complicated emission patterns consisting of many transverse modes and associated intensity pulsations at beat frequencies between some pairs of transverse eigenmodes in microchip solid-state lasers with laser-diode asymmetric end-pumping are reviewed. The dependence of billiard-like transverse patterns on pump power and crystal rotation (i.e. kaleidoscopic patterns) was demonstrated i...<br/><br/>K Otsuka, J Y Ko, H Makino, T Ohtomo, A Okamoto (2003) <i>JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 5: 3 R137-R145<br/>

http://publicationslist.org/kenju.otsuka/refid41 2009-11-11T05:38:29Z

We studied the antiphase self-pulsation in a globally coupled three-mode laser operating in different optical spectrum configurations. We observed locking of modal pulsation frequencies, quasiperiodicity, clustering behaviors, and chaos, resulting from the nonlinear interaction among modes. The robustness of [p:q:r] three-frequency locking states and quasiperiodic oscillations against residual noi...<br/><br/>K Otsuka, T Ohtomo, T Maniwa, H Kawasaki, J Y Ko (2003) <i>CHAOS</i> <i></i> <i></i> 13: 3 1014-1025<br/>

http://publicationslist.org/kenju.otsuka/refid39 2009-11-11T05:38:29Z

K Otsuka, K Abe, J Y Ko, T S Lim (2003) <i>OPTICS LETTERS</i> <i></i> <i></i> 28: 22 2267-2267<br/>

http://publicationslist.org/kenju.otsuka/refid53 2009-11-11T05:39:22Z

We observed a highly efficient self-induced "oval hollow" mode operation in a Fabry-Perot microchip solid-state laser under strongly asymmetric "sheetlike" end-pumping. This new class of microresonator lasing mode features a hollow emission near-field pattern with a dark spot inside and a narrow unidirectional line-shape far-field pattern with a uniform intensity distribution.<br/><br/>K Otsuka, J Y Ko, T Fukazawa (2002) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 41: 3A L252-L255<br/>

http://publicationslist.org/kenju.otsuka/refid54 2009-11-11T05:39:22Z

Relative intensity fluctuations in single-mode class B lasers, i.e., a laser diode (LD) and a microchip Nd:YVO4 solid-state laser (SSL), were examined. Experimental observations revealed significant difference in the characteristics of the LD and the SSL. A stochastic laser model and the Fokker-Planck equation approach were used, and reduced moment equations were developed, A close agreement was a...<br/><br/>T S Lim, J L Chern, K Otsuka (2002) <i>OPTICS LETTERS</i> <i></i> <i></i> 27: 12 1037-1039<br/>

http://publicationslist.org/kenju.otsuka/refid52 2009-11-11T05:39:22Z

Stokes-like IR (1560-1600-nm) emissions, which have been observed in laser-diode- (LD-) pumped microchip Nd-doped lasers, are re-examined experimentally. Dependences of IR emissions on pump wavelengths, pump densities, and operating temperatures are studied. The response of IR emissions to coherent probe-beam injection is investigated by use of a tunable LD light source. Optical phonons emitted th...<br/><br/>J L Chern, T Kubota, T S Lim, K Otsuka (2002) <i>JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS</i> <i></i> <i></i> 19: 7 1668-1675<br/>

http://publicationslist.org/kenju.otsuka/refid56 2009-11-11T05:39:22Z

Joint time-frequency analysis (JTFA) which expands signal in both time and frequency domain is widely used to study non-stationary time series. In this paper, a generalized JTFA is proposed to study the synchronization of chaos. A similarity function constructed from generalized time-frequency spectra was used to reveal phase portrait of synchronized chaos. This scheme is applied to analyze the ex...<br/><br/>J S Lih, J L Chern, K Otsuka (2002) <i>EUROPHYSICS LETTERS</i> <i></i> <i></i> 57: 6 810-816<br/>

http://publicationslist.org/kenju.otsuka/refid47 2009-11-11T05:38:29Z

We applied laser-diode sheetlike end pumping to a multimode Nd:YVO4 laser and observed high-speed (>400-MHz) modulation of the intensity of chaotic pulsation near 1 MHz. The frequencies of modulation were the beat frequencies for pairs of closely spaced lasing modes. Asymmetric optical confinement and the resultant modal interference are shown to lead to oval-hollow-mode operation in which modal b...<br/><br/>K Otsuka, T S Lim, J Y Ko, H Makino (2002) <i>OPTICS LETTERS</i> <i></i> <i></i> 27: 19 1696-1698<br/>

http://publicationslist.org/kenju.otsuka/refid51 2009-11-11T05:39:22Z

Nanometer vibration analysis of a target has been demonstrated by a self-aligned optical feedback vibrometry technique that uses a laser-diode-pumped microchip solid-state laser. The laser output waveform, which was modulated through interference between a lasing field and an extremely weak (< -100-dB) frequency-modulated (FM) feedback field, was analyzed by the Hilbert transformation to yield the...<br/><br/>K Otsuka, K Abe, J Y Ko, T S Lim (2002) <i>OPTICS LETTERS</i> <i></i> <i></i> 27: 15 1339-1341<br/>

http://publicationslist.org/kenju.otsuka/refid48 2009-11-11T05:38:29Z

We study chaos synchronization experimentally in a modulated globally coupled three-mode laser with different modal gains subjected to self-mixing Doppler-shifted feedback, which can apply the loss modulation to individual modes at Doppler-shift frequencies. Depending on the pump power, different forms of collective chaos synchronizations were found to appear when the laser was modulated at the hi...<br/><br/>K Otsuka, T Ohtomo, A Yoshioka, J Y Ko (2002) <i>CHAOS</i> <i></i> <i></i> 12: 3 678-687<br/>

http://publicationslist.org/kenju.otsuka/refid46 2009-11-11T05:38:29Z

We examine higher-order photon statisitics of laser diodes (LDs) and microchip solid-state lasers (SSLs). When the lasers are operated above lasing threshold, significantly different features of fluctuations are exhibited, which are the result of the asymmetric non-Gaussian distribution characteristics that are always present in SSLs, whereas, in contrast, Gaussian fluctuation persists in LDs. It ...<br/><br/>T S Lim, J L Chern, K Otsuka (2002) <i>OPTICS LETTERS</i> <i></i> <i></i> 27: 24 2197-2199<br/>

http://publicationslist.org/kenju.otsuka/refid49 2009-11-11T05:38:29Z

We observed complicated emission patterns consisting of different transverse modes and associated intensity pulsations at beat frequencies between pairs of transverse eigenmodes in a solid-state thin-slice Fabry-Perot laser with asymmetric end-pumping. The dependence of transverse patterns and pulsation frequencies on pump power has been demonstrated. The interference among nonorthogonal transvers...<br/><br/>K Otsuka, J Y Ko, T S Lim, H Makino (2002) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 89: 8 <br/>

http://publicationslist.org/kenju.otsuka/refid61 2009-11-11T05:39:22Z

We report the instability behaviors of a single-mode microchip solid-state laser subjected to external feedback. Two kinds of instabilities, random chaotic burst generations and random sinusoidal burst generations, were observed experimentally in an LD-pumped microchip Nd:YVO4 single-mode solid-state laser with fiber feedback. These results are totally different form those observed in laser diodes...<br/><br/>T S Lim, T H Yang, J L Chern, K Otsuka (2001) <i>IEEE JOURNAL OF QUANTUM ELECTRONICS</i> <i></i> <i></i> 37: 9 1215-1225<br/>

http://publicationslist.org/kenju.otsuka/refid60 2009-11-11T05:39:22Z

Random chaotic burst generation was experimentally observed in a single-mode microchip Nd:YVO4 laser with fiber feedback. As the feedback strength was increased, a transition from stable relaxation oscillation state to unstable random chaotic burst state appeared. Furthermore, the non-stationary characteristic of probability association was experimentally identified at the transition of the two st...<br/><br/>T H Yang, T S Lim, J L Chern, K Otsuka (2001) <i>EUROPEAN PHYSICAL JOURNAL D</i> <i></i> <i></i> 15: 3 365-371<br/>

http://publicationslist.org/kenju.otsuka/refid59 2009-11-11T05:39:22Z

This paper reviews our recent research on nonlinear dynamics of microchip solid-state lasers subjected to delayed optical feedback. Instabilities in two types of physical systems including multimode lasers with feedback and lasers with frequency-shifted feedback are discussed. Applications of microchip lasers with feedback to shot-noise-limited self-mixing optical sensing and imaging are summarize...<br/><br/>J Y Ko, T Ohtomo, K Abe, K Otsuka (2001) <i>INTERNATIONAL JOURNAL OF MODERN PHYSICS B</i> <i></i> <i></i> 15: 26 3369-3395<br/>

http://publicationslist.org/kenju.otsuka/refid58 2009-11-11T05:39:22Z

A two-mode solid-state laser subjected to a delayed optical feedback is studied. Simultaneous random switchings between stable and chaotic antiphase spiking oscillations featuring the establishment of causal (drive response) relationships among modes have been demonstrated by a proposed information circulation analysis of an experimental time series. The observed phenomenon has been well reproduce...<br/><br/>K Otsuka, J Y Ko, T Ohtomo, K Ohki (2001) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 64: 5 art. no.-056239<br/>

http://publicationslist.org/kenju.otsuka/refid62 2009-11-11T05:39:22Z

Dynamical instability, chaotic pulsations, and generalized bistability have been observed in a laser-diode-pumped microchip Nd:YAG laser operating in a double transition scheme in which lasing occurs on two transitions with overlapping gain profiles, F-4(3/2)(2) --> I-4(11/2)(3) and F-4(3/2)(1) --> I-4(11/2)(2), and simultaneously involves excited Nd atoms from different sublevels of the upper man...<br/><br/>K Otsuka, J Y Ko, T Kubota, S L Hwong, T S Lim, J L Chern, B A Nguyen, P Mandel (2001) <i>OPTICS LETTERS</i> <i></i> <i></i> 26: 14 1060-1062<br/>

http://publicationslist.org/kenju.otsuka/refid63 2009-11-11T05:39:22Z

A kind of chaotic oscillations featuring random switching between sustained relaxation oscillations (RO) and spiking oscillations (SO) has been demonstrated in lasers with frequency-shifted feedback. The presence of stochastic frequency locking between two periodicities of RO and SO motions and selective quantum-noise-induced ordering of chaotic spiking oscillations is demonstrated theoretically a...<br/><br/>J Y Ko, K Otsuka, T Kubota (2001) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 86: 18 4025-4028<br/>

http://publicationslist.org/kenju.otsuka/refid64 2009-11-11T05:39:22Z

Self-induced pulsations that are associated with atomic interference have been found in a laser-diode-pumped LiNdP4O12 microchip laser with an intracavity KTP frequency-doubling crystal operating in a h scheme. The instability and peculiar pulsations that were observed have been verified by a linear stability analysis and numerical simulation of two-mode laser equations, including nonlinear absorp...<br/><br/>K Otsuka, J Y Ko, S Higashihara, J L Chern (2001) <i>OPTICS LETTERS</i> <i></i> <i></i> 26: 8 536-538<br/>

http://publicationslist.org/kenju.otsuka/refid69 2009-11-11T05:39:22Z

Synchronization of mutually coupled chaotic lasers has been demonstrated in a microchip LiNdP4O12 laser array with self-mixing feedback modulation. An abrupt transition to synchronized chaos by way of "phase squeezing" was observed when coupling between the two lasers was increased. This phenomenon is well reproduced by numerical calculations using model equations. It is also shown that low energy...<br/><br/>K Otsuka, R Kawai, S L Hwong, J Y Ko, J L Chern (2000) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 84: 14 3049-3052<br/>

http://publicationslist.org/kenju.otsuka/refid68 2009-11-11T05:39:22Z

1.5-mu m emissions from Nd:YAG, Nd:YVO4, and LiNdP4O12 microchip lasers pumped by laser diodes have been observed. These coherent emissions are attributed to the effect of high-energy modified lattice vibration owing to the existence of Nd ions as well as to stimulated intracavity Raman scattering enhanced by the microchip configuration. A four-wave mixing process involving two lasing fields and a...<br/><br/>S L Hwong, J L Chern, K Otsuka, Y H Huang, R Kawai, K Ohki (2000) <i>OPTICS LETTERS</i> <i></i> <i></i> 25: 9 646-648<br/>

http://publicationslist.org/kenju.otsuka/refid67 2009-11-11T05:39:22Z

We report on recent experimental results of the dynamics of a laser-diode-pumped free-running Nd:YVO4 laser operating in a two-mode regime. We observe intrinsic quasiperiodic and chaotic oscillations as well as a locking of pulsation frequencies. We perform an asymptotic analysis of model rate equations in which an intensity-dependent cross-gain (i.e., nonlinear gain) mechanism of direct mode-mode...<br/><br/>K Otsuka, S L Hwong, B A Nguyen (2000) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 61: 5 art. no.-053815<br/>

http://publicationslist.org/kenju.otsuka/refid66 2009-11-11T05:39:22Z

A simple laser vibrometer system (LVS) has been built around a laser-diode-pumped microchip LiNdP4O12 (LNP) laser combined with an acousto-optic frequency shifter, using an efficient self-mixing modulation arising from the interference between a laser field and a weak field that is fed back from a rough vibrating target. The LVS provides a 50 dB carrier-to-noise ratio for 3kHz bandwidth, even when...<br/><br/>K Otsuka, T Fukazawa, N Sekita, S Higashihara (2000) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 39: 7B L763-L765<br/>

http://publicationslist.org/kenju.otsuka/refid77 2009-11-11T05:39:22Z

In a LiNdP4O12 microchip laser pumped by a diode laser, atomic interference arise due to the simultaneous oscillation on two transitions forming a Lambda configuration. For a microchip laser, the low-frequency coherence is an important dynamical variable. It is coupled to the low spatial frequency of the population inversion grating. This results in modal intensities which are self-pulsing while t...<br/><br/>K Otsuka, E A Viktorov, P Mandel (1999) <i>EUROPHYSICS LETTERS</i> <i></i> <i></i> 45: 3 307-313<br/>

http://publicationslist.org/kenju.otsuka/refid75 2009-11-11T05:39:22Z

K Otsuka (1999) <i>PROGRESS IN QUANTUM ELECTRONICS</i> <i></i> <i></i> 23: 3 97-129<br/>

http://publicationslist.org/kenju.otsuka/refid76 2009-11-11T05:39:22Z

A self-mixing laser Doppler velocimetry (LDV) has been demonstrated with laser-diode-pumped microcavity LiNdP4O12 lasers. The feedback signal required for a usable measurement without using photon-correlation techniques was <1 photon per Doppler-beat cycle. an enhancement of LDV signals by resonant excitations of relaxation oscillations has been performed.<br/><br/>R Kawai, Y Asakawa, K Otsuka (1999) <i>IEEE PHOTONICS TECHNOLOGY LETTERS</i> <i></i> <i></i> 11: 6 706-708<br/>

http://publicationslist.org/kenju.otsuka/refid73 2009-11-11T05:39:22Z

Self-induced Q-switching-type spiking oscillations and associated instabilities have been observed in a free-running laser-diode-pumped microchip Nd:YVO4 laser operating in three-mode regimes, and dynamical characterizations of spiking pulsations have been demonstrated. Observed instabilities have been reproduced by numerical simulations of the model equations including intensity-dependent cross-g...<br/><br/>K Otsuka, H Utsu, R Kawai, K Ohki, Y Asakawa, S L Hwong, J Y Ko, J L Chern (1999) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 38: 9AB L1025-L1028<br/>

http://publicationslist.org/kenju.otsuka/refid74 2009-11-11T05:39:22Z

Simultaneous single-frequency oscillations on different transitions have been observed experimentally in a laser-diode-pumped microchip LiNdP4O12 laser. The peculiar modal input-output characteristics and the antiphase relaxation oscillation dynamics have been reproduced theoretically using rate equations, including the strong spatial localization of population inversions, cross saturation, and re...<br/><br/>R Kawai, Y Asakawa, K Otsuka (1999) <i>IEEE JOURNAL OF QUANTUM ELECTRONICS</i> <i></i> <i></i> 35: 10 1542-1547<br/>

http://publicationslist.org/kenju.otsuka/refid65 2009-11-11T05:39:22Z

Input-output characteristics and multimode oscillation properties have been investigated in laser-diode-pumped microchip LiNdP4O12 lasers under different pump-beam focusing conditions, using microscope objective lenses with varying magnifications. The lasing threshold and slope efficiency, as well as the number of oscillating modes, are shown to depend on the pump-beam radius. The results are expl...<br/><br/>Y Asakawa, R Kawai, K Ohki, K Otsuka (1999) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 38: 5A L515-L517<br/>

http://publicationslist.org/kenju.otsuka/refid70 2009-11-11T05:39:22Z

Brillouin scattering has been measured with a high degree of sensitivity by a system built around a laser-diode-pumped microchip LiNdP4O12 laser. An efficient self-mixing modulation effect that is due to the interference between a lasing field and a weak field fed back from an acousto-optic modulator by means of a phase-conjugate reflection was used. Laser-Doppler velocimetry that can discriminate...<br/><br/>K Otsuka, R Kawai, Y Asakawa, T Fukazawa (1999) <i>OPTICS LETTERS</i> <i></i> <i></i> 24: 24 1862-1864<br/>

http://publicationslist.org/kenju.otsuka/refid71 2009-11-11T05:39:22Z

Random chaotic relaxation oscillation burst generations have been observed in laser-diode-pumped microchip multimode lasers coupled to a single-mode optical fiber. Dynamical characterizations have been carried out by the singular value decomposition method and the joint time-frequency analysis, and the observed instability has been identified to be a random switching between stable and chaotic ope...<br/><br/>K Otsuka, J Y Ko, J L Chern, K Ohki, H Utsu (1999) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 60: 5 R3389-R3392<br/>

http://publicationslist.org/kenju.otsuka/refid72 2009-11-11T05:39:22Z

Efficient simultaneous intracavity second-harmonic and sum-frequency generation that is free from irregular large amplitude fluctuations (the so-called green problem) is achieved with a laser-diode-pumped LiNdP4O12 (LNP) laser with a type II phase-matching KTiODPO4 crystal. Observed frequency-mixing operations result from the simultaneous single-frequency oscillations can different transitions tha...<br/><br/>K Otsuka, R Kawai, Y Asakawa (1999) <i>OPTICS LETTERS</i> <i></i> <i></i> 24: 22 1611-1613<br/>

http://publicationslist.org/kenju.otsuka/refid80 2009-11-11T05:39:22Z

Simultaneous single-mode oscillations on different transitions were observed in a laser-diode-pumped microchip LiNdP4O12 laser. The unusual modal-output characteristics of the laser were reproduced by multitransition-oscillation laser model equations that include cross saturation of population inversions with a strong spatial exponential decay and transition-dependent resonant reabsorption loss. (...<br/><br/>K Otsuka, R Kawai, Y Asakawa, P Mandel, E A Viktorov (1998) <i>OPTICS LETTERS</i> <i></i> <i></i> 23: 3 201-203<br/>

http://publicationslist.org/kenju.otsuka/refid78 2009-11-11T05:39:22Z

The dynamics of relaxation oscillations has been investigated in a free-running laser-diode-pumped microchip multimode Nd:YVO4 laser. The locking of relaxation oscillation frequencies, and quasi-periodic and chaotic oscillations have been observed in two-mode regimes. The cross-gain coupling among modes is proposed to explain the observed instabilities.<br/><br/>K Otsuka, Y Asakawa, R Kawai, S L Howng, J L Chern (1998) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 37: 12B L1523-L1526<br/>

http://publicationslist.org/kenju.otsuka/refid84 2009-11-11T05:39:22Z

A nonlinear response of a laser-diode-pumped microchip LiNdP4O12 (LNP) multimode laser that is subjected to multiple-frequency modulations is investigated. Clustering and breathing motions featuring intermode parametric resonances are demonstrated when the LNP laser was modulated by rational frequencies chosen to be nearly resonant to multiple relaxation-oscillation frequencies inherent in multimo...<br/><br/>K Otsuka, D Pieroux, J Y Wang, P Mandel (1997) <i>OPTICS LETTERS</i> <i></i> <i></i> 22: 8 516-518<br/>

http://publicationslist.org/kenju.otsuka/refid86 2009-11-11T05:39:22Z

Suppressing chaotic behavior by addition of a weak second periodic perturbation signal, which is nearly resonant to a subharmonic of the fundamental system frequency, is observed in a modulated microchip LiNdP4O12 multimode laser by a highly sensitive self-mixing modulation technique. The stabilization of the unstable period-2 orbit embedded in a chaotic attractor is demonstrated in a wide paramet...<br/><br/>K Otsuka, J L Chern, J S Lih (1997) <i>OPTICS LETTERS</i> <i></i> <i></i> 22: 5 292-294<br/>

http://publicationslist.org/kenju.otsuka/refid83 2009-11-11T05:39:22Z

We present an asymptotic study of a three-mode Fabry-Perot laser with arbitrary relative modal gains in the rate equation limit. Dynamical modes are defined as the eigenvectors of the stability or Jacobian matrix. The associated eigenvalues are the decay rates and the relaxation oscillation frequencies. We show that if the modal gains are not equal, the ratio of the relaxation oscillation frequenc...<br/><br/>P Mandel, B A Nguyen, K Otsuka (1997) <i>QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 9: 3 365-380<br/>

http://publicationslist.org/kenju.otsuka/refid82 2009-11-11T05:39:22Z

The effect of high-density pumping on lasing mode spectra is investigated in a laser-diode pumped microchip LiNdP4O12, (LNP) laser. Breakup of multimode oscillations, leading to single-mode oscillations, is observed experimentally. It is shown analytically that the enhanced Auger recombination process among excited Nd ion pairs results in a strong deformation of spatial hole-burning patterns, lead...<br/><br/>K Otsuka, P Mandel, E A Viktorov (1997) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 56: 4 3226-3232<br/>

http://publicationslist.org/kenju.otsuka/refid81 2009-11-11T05:39:22Z

Antiphase dynamics in globally coupled optical systems are investigated numerically in the model of intracavity second-harmonic generation in multimode lasers. Clustering, grouping of antiphase motions, and self-induced chaotic switching among a factorial number of coexisting grouping states, leading to antiphase periodic states, are found to occur when a pump parameter is increased. Dynamical cha...<br/><br/>K Otsuka, Y Sato, J L Chern (1997) <i>PHYSICAL REVIEW E</i> <i></i> <i></i> 56: 4 4765-4772<br/>

http://publicationslist.org/kenju.otsuka/refid89 2009-11-11T05:39:22Z

We investigate the properties of power spectra of a two-mode laser and predict that universal relations among the peaks of the power and noise spectra for different modes but the same frequency hold for deterministic and stochastic perturbations. These results are confirmed experimentally.<br/><br/>P Mandel, K Otsuka, J Y Wang, D Pieroux (1996) <i>PHYSICAL REVIEW LETTERS</i> <i></i> <i></i> 76: 15 2694-2697<br/>

http://publicationslist.org/kenju.otsuka/refid88 2009-11-11T05:39:22Z

We propose a model for globally coupled lasers with intracavity second harmonic generation in which each laser gain is modulated separately. Suitable selection of the modulation phases can shift the resonance expected at the relaxation oscillation towards tower frequencies. This shift is accompanied by a reduction of the resonance width.<br/><br/>J Y Wang, P Mandel, K Otsuka (1996) <i>QUANTUM AND SEMICLASSICAL OPTICS</i> <i></i> <i></i> 8: 3 399-403<br/>

http://publicationslist.org/kenju.otsuka/refid87 2009-11-11T05:39:22Z

Coexistence of periodic states with antiphase periodic states or with grouping states, which consist of qualitatively different motions, is predicted in the model of globally coupled modulated multimode lasers. It is shown that the injection seeding can switch the system from periodic states to antiphase periodic states or to grouping states, which are composed of a large-amplitude periodic (chaot...<br/><br/>K Otsuka, Y Sato, J L Chern (1996) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 54: 5 4464-4472<br/>

http://publicationslist.org/kenju.otsuka/refid95 2009-11-11T05:39:22Z

The response of an N-mode solid-state laser when the output field is reinjected in the cavity after N frequency shifts is analyzed. The results obtained with up to four modes are described and it is tried to infer general rules. The emphasis is on comparing the dynamics of the partial and the total mode intensities.<br/><br/>D PIEROUX, P MANDEL, K OTSUKA (1994) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 108: 4-6 273-277<br/>

http://publicationslist.org/kenju.otsuka/refid96 2009-11-11T05:39:22Z

Highly sensitive laser Doppler velocimetry featuring the simultaneous measurement of light-scattering objects moving at different velocities and vibration sensing based on Doppler-shifted light-injection-induced intensity modulation in an externally pumped microchip solid-state laser is demonstrated.<br/><br/>K OTSUKA (1994) <i>APPLIED OPTICS</i> <i></i> <i></i> 33: 6 1111-1114<br/>

http://publicationslist.org/kenju.otsuka/refid102 2009-11-11T06:48:03Z

Otsuka, Aizawa (1994) <i>Phys Rev Lett</i> 72: 17 2701-2704<br/>

http://publicationslist.org/kenju.otsuka/refid94 2009-11-11T05:39:22Z

2N-1 different periodic oscillations are obtained experimentally in a microchip N-mode laser by different combinations of modulations at multiple relaxation oscillation frequencies that appear on the basis of antiphase dynamics among lasing modes. Application of mode-dependent periodic oscillations to generation of dynamic spatial patterns is demonstrated using a shear plate interferometer.<br/><br/>K OTSUKA, D PIEROUX, P MANDEL (1994) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 108: 4-6 265-272<br/>

http://publicationslist.org/kenju.otsuka/refid93 2009-11-11T05:39:22Z

We analyze a two-mode laser; described by rate equations, whose gain is periodically modulated. The nature of the response varies significantly with the modulation amplitude. We study both the small modulation in which the pump parameter remains always above the lasing threshold for the second mode, and the deep modulation in which the pump parameter is located during part of the,cycle between the...<br/><br/>M GEORGIOU, P MANDEL, K OTSUKA (1994) <i>IEEE JOURNAL OF QUANTUM ELECTRONICS</i> <i></i> <i></i> 30: 3 854-859<br/>

http://publicationslist.org/kenju.otsuka/refid90 2009-11-11T05:39:22Z

The underlying physical processes inherent in self-organized antiphase dynamics in multi-longitudinal-mode lasers are explored in terms of gain circulation, a new physical quantity. Transverse effects on antiphase dynamics in multi-longitudinal-mode lasers are investigated, and three-dimensional self-organization is shown to result from the cross-saturation dynamics in the longitudinal and transve...<br/><br/>K OTSUKA (1994) <i>CHAOS SOLITONS & FRACTALS</i> <i></i> <i></i> 4: 8-9 1547-1558<br/>

http://publicationslist.org/kenju.otsuka/refid91 2009-11-11T05:39:22Z

We analyze temporal variations in local Lyapunov exponents for chaotic spiking lasers in terms of standard deviation and Allan variance as a function of integral time tau. We show that standard deviations for local Lyapunov exponents become saturated in short tau regimes. The calculated Allan variance and power spectrum analysis suggest that the transition between stationary and nonstationary ch...<br/><br/>K OTSUKA, JL CHERN (1994) <i>INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS</i> <i></i> <i></i> 4: 4 1053-1060<br/>

http://publicationslist.org/kenju.otsuka/refid92 2009-11-11T05:39:22Z

A minimal model for a laser with delayed feedback is analyzed. The model is motivated by two independent studies of a laser controlled by a fully optical feedback [Otsuka and Chem, Opt. Lett. 16, 1759 (1991)] and a laser with an optoelectronic feedback [Loiko and Samson, Opt. Commun. 93, 66 (1992)]. By reformulating the original laser equations in terms of dimensionless quantities, we obtain a sim...<br/><br/>D PIEROUX, T ERNEUX, K OTSUKA (1994) <i>PHYSICAL REVIEW A</i> <i></i> <i></i> 50: 2 1822-1829<br/>

http://publicationslist.org/kenju.otsuka/refid101 2009-11-11T05:40:02Z

Antiphase periodic oscillatlons and clustering in a modulated microchip multimode solid-state laser have been demonstrated experimentally. Chaotic relaxation oscillations featuring intermode statistical non-independence that result from cross-saturation dynamics among oscillating modes have been observed.<br/><br/>K OTSUKA, P MANDEL, M GEORGIOU, C ETRICH (1993) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 32: 3A L318-L321<br/>

http://publicationslist.org/kenju.otsuka/refid100 2009-11-11T05:39:22Z

We derive a set of multimode rate equations which couple the complex fields to the mean number of amplifiers. We show that in the case of semiconductor lasers, phase-sensitive interactions must be retained. The resulting equations are studied and bifurcation diagrams are presented that display the steady, periodic, and quasiperiodic solutions.<br/><br/>P MANDEL, C ETRICH, K OTSUKA (1993) <i>IEEE JOURNAL OF QUANTUM ELECTRONICS</i> <i></i> <i></i> 29: 3 836-843<br/>

http://publicationslist.org/kenju.otsuka/refid99 2009-11-11T05:39:22Z

We apply information theory to the study of chaotic itinerancy in a globally coupled multimode laser model. Structure changes are found in the self-information flow, corresponding to switching among destabilized clustered states. The inhomogeneity in the self-information flows among modes shows that different information transport structures are created by cluster switching in chaotic itinerancy.<br/><br/>JL CHERN, K OTSUKA (1993) <i>PHYSICS LETTERS A</i> <i></i> <i></i> 176: 3-4 213-219<br/>

http://publicationslist.org/kenju.otsuka/refid97 2009-11-11T05:39:22Z

Transverse effects on antiphase dynamics in a multi-longitudinal-mode solid-state laser are investigated experimentally We show a three-dimensional self-organization resulting from the cross saturation dynamics in the longitudinal and transverse directions, in which the intensity noise spectrum of partial output within the beam cross-section possesses the antiphase relaxation oscillation component...<br/><br/>K OTSUKA (1993) <i>JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS</i> <i></i> <i></i> 32: 10A L1414-L1417<br/>

http://publicationslist.org/kenju.otsuka/refid98 2009-11-11T05:39:22Z

The two-mode rate equations for a laser in a Fabry-Perot cavity are studied, taking into account the dynamics of spatial hole-burning. We prove analytically that each mode intensity has a transient behavior characterized by two damped oscillation frequencies, while the total intensity displays a domain where only the largest oscillation frequency remains; this domain appears to display antiphase d...<br/><br/>P MANDEL, M GEORGIOU, K OTSUKA, D PIEROUX (1993) <i>OPTICS COMMUNICATIONS</i> <i></i> <i></i> 100: 1-4 341-350<br/>

http://publicationslist.org/kenju.otsuka/refid106 2009-11-11T06:50:35Z

K Otsuka, J L Chern (1992) <i>Opt Lett</i> <i></i> <i></i> 17: 10 <br/>

http://publicationslist.org/kenju.otsuka/refid107 2009-11-11T06:50:35Z

Otsuka, Chern (1992) <i>Phys Rev A</i> <i></i> <i></i> 45: 7 5052-5055<br/>

http://publicationslist.org/kenju.otsuka/refid105 2009-11-11T06:50:35Z

Otsuka, Chern (1992) <i>Phys Rev A</i> <i></i> <i></i> 45: 11 8288-8291<br/>

http://publicationslist.org/kenju.otsuka/refid104 2009-11-11T06:50:35Z

Otsuka, Mandel, Bielawski, Derozier, Glorieux (1992) <i>Phys Rev A</i> <i></i> <i></i> 46: 3 1692-1695<br/>

http://publicationslist.org/kenju.otsuka/refid103 2009-11-11T06:50:35Z

Otsuka, Chern (1992) <i>Phys Rev A</i> <i></i> <i></i> 46: 5 <br/>

http://publicationslist.org/kenju.otsuka/refid109 2009-11-11T06:50:35Z

Otsuka (1991) <i>Phys Rev Lett</i> <i></i> <i></i> 67: 9 1090-1093<br/>

http://publicationslist.org/kenju.otsuka/refid108 2009-11-11T06:50:35Z

A novel method for producing high-speed picosecond optical pulses from semiconductor laser diodes that uses incoherent optical feedback is proposed. The incoherent optical feedback provides a successive pulselike modulation in carrier density and drives the system to a self-sustained pulsation state whose repetition rate is determined by relaxation oscillations.<br/><br/>K Otsuka, J L Chern (1991) <i>Opt Lett</i> <i></i> <i></i> 16: 22 1759-1761<br/>

http://publicationslist.org/kenju.otsuka/refid110 2009-11-11T06:50:35Z

Otsuka (1990) <i>Phys Rev Lett</i> <i></i> <i></i> 65: 3 329-332<br/>

http://publicationslist.org/kenju.otsuka/refid111 2009-11-11T06:50:35Z

Mukai, Otsuka (1985) <i>Phys Rev Lett</i> <i></i> <i></i> 55: 17 1711-1714<br/>