bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser Focal Electroretinography Reveals Unique Macular Responses
Authors: Gouras P. , Lopez R. , Yamamoto S. , Rosskothen H.
Published: February 2023

We have constructed an instrument that allows us to view the fundus and a laser beam that can be shifted to different positions on the retina. The helium-neon laser subtends approximately 3° of visual angle and is square wave flickered with equal light/dark cycles at 5.1 Hertz. We can shift from a 633 nm to a 544 nm laser allowing a comparison of responses to two different parts of the spectrum. The electroretinogram (ERG) produced by the flicker is detected by an electrode embedded in a corneal contact lens. Retinal adaptation is maintained by a steady white light, bright enough to permit easy viewing of the fundus and to minimize responses to scattered light and sufficient to completely saturate rod responses. The studies reported here have been carried out on four eyes of two normal rhesus monkeys tested under anesthesia repeatedly over a period of one year.
Assessment of Color Vision Anomalies with the VEP
Authors: Crognale Michael A. , Switkes Eugene , Rabin Jeff , Haegerstrom-Portnoy Gunilia , Adams Anthony J.
Published: February 2023

We have employed the VEP in an effort to develop an objective and sensitive technique for studying the basic mechanisms underlying color vision as well as those underlying color vision anomalies. In addition to the common congenital color defiicits, we have applied this technique to a wide variety of acquired color vision anomalies. For example, many ocular diseases, including glaucoma, diabetic retinopathy, retinitis pigmentosa and central serous choroidopathy are characterized by a loss of short wavelength sensitivity (Marre and Marre, 1972; Sandberg and Berson, 1977; Adams et al., 1982; Adams et al., 1987; Greenstein et al. 1989). In many cases, color vision changes can occur prior to overt symptoms as evidenced from conventional clinical tests. Thus, measures which reveal the selective losses would be advantageous for early detection and treatment of such diseases. Most previous studies involved psychophysical thresholds; few have attempted to objectively quantify color losses at suprathreshold levels. In addition, a unifying framework within which selective pathway losses can be compared has been lacking.
Clinical microscopy of the cornea utilizing optical sectioning and a high numerical aperture objective
Authors: Koester Charles J. , Auran James D. , Rosskothen Heinz D. , Florakis George J. , Brady James , Tackaberry Robert B.
Published: February 2023

High magnification, clinical microscopy of the cornea has been made practical by the use of optical elements that contact the surface(1), thereby establishing focus and damping involuntary lateral movements. Specular microscopes, used for examination of the endothelial cell layer, make use of so-called dipping cones that attach to the front of a long working distance objective. Generally they employ a flat front surface and a spherical rear surface that is concentric to the focal plane. This design increases the numerical aperture of the system by a factor equal to the refractive index of the cone material. The aberrations introduced are negligible for low numerical aperture systems, typically NA 0.35. While this numerical aperture is sufficient for endothelial and superficial epithelial cell examinations, a higher resolution is desirable for studies of detail within the stroma.
Development of Myopia in Infants with Birth Weights Less than 1251G
Authors: Quinn Graham E. , Dobson Velma , Repka Michael X. , Reynolds James , Kivlin Jane , Davis Barry , Buckley Edward , Flynn John T. , Palmer Earl A.
Published: February 2023

Myopia is common among premature infants and frequently persists into
later life.1-6 The causes of myopia in this population are
not certain, but the presence of retinopathy of prematurity (ROP)
during the child's neonatal course and the retinal residua of ROP are
associated with a higher incidence of myopia.7-12 The
influence on the development of myopia of visual
deprivation,13 central nervous system abnormalities, and
other ocular disorders14, 15 that are more
common in the premature population is not known.
Cone Optical Density and Foveal Architecture in Patients with Hereditary Photoreceptor Degenerations
Authors: Swanson William H. , Fish Gary E.
Published: February 2023

A century has passed since it was first reported that an observer's anomaloscope setting (Rayleigh match) can be affected by field size, with less red light required for smaller fields. This phenomenon, known as the color-match area effect, appears to be due to longer cone outer segments in the foveola than in the parafovea, which results in higher effective optical density of foveolar cone photopigments. Since Rayleigh match midpoints are determined by ratio of quantal catches in the cone outer segments for the different wavelengths, they will not be affected by reduced numbers of cones, changes in the gain of the cone signals, or postreceptoral processing (these other factors may affect match width, but not midpoint). Therefore, the color-match area effect can be used as a noninvasive measure of the integrity of foveal architecture1 (i.e., the normal increase in cone outer segment length from parafovea to foveola and normal outer segment alignment). A reduced or absent color-match area effect would reflect abnormal foveal architecture, including a relative decrease in the length of the foveolar cone outer segments or a tilting of the plane of the photoreceptors.
Push-Pull Mechanism of the Primate Photopic Electroretinogram B-Wave
Authors: Sieving Paul A. , Murayama Koichiro , Naarendorp Franklin
Published: February 2023

The PI, PII, and PIII fundamental "Processes" described by Granit (1933) form the major component waves of the electroretinogram (ERG), particularily under dark-adapted (scotopic) conditions. The leading edge of scotopic PIII (i.e. "fast PIII") shapes the negative a-wave which originates directly from light evoked hyperpolarization of rod photoreceptors (Penn and Hagins, 1969). Scotopic PII is seen primarily as the phasic positive b-wave which results from local depolarization of Muller glial cells by a light-evoked K+ efflux from bipolar cells in distal retina (Faber, 1969; Miller and Dowling, 1970)
Validation of a Predictive Model of Clinical Measures of Visual Function
Authors: Lang Alan , Lakshminarayanan Vasudevan , Portney Valdemar
Published: February 2023

At the 1992 NAVS/OVO meeting1, we introduced a phenomenological model (called Expected Visual Outcome) which is intended to predict clinical function (e.g., contrast sensitivity, through-focus-acuity, etc.) base on in-vitro modulation transfer function (MTF) measurements of intraocular lens (IOL) performance2. In this paper, we discuss the validation of this model using individual patient data derived from the AMO ArrayTM multifocal IOL clinical study3.
Pupil Perimetry by Real-time Analysis of Digitized Video Images
Authors: Weiss Stefan , Schaeffel Frank , Wilhelm Helmut , Zrenner Eberhart
Published: February 2023

A simple set-up is presented that permits highly precise real-time pupil perimetry with a personal computer, a video board and a video camera.
Relationship Between Visual Acuity and Contrast Sensitivity Deficits in Retinitis Pigmentosa
Authors: Alexander Kenneth R. , Derlacki Deborah J. , Fishman Gerald A.
Published: February 2023

Retinitis pigmentosa (RP) refers to a group of retinal dystrophies that are characterized typically by night blindness, peripheral visual field restrictions and/or scotomas, abnormalities in the electroretinogram (ERG), intraretinal bone spicule-like pigmentation, and narrowing of the retinal vessels. While functional abnormalities are usually most apparent in the peripheral visual field, foveal function can often be impaired as well. Previous studies have suggested that not only can foveal visual acuity be reduced in RP patients, but foveal contrast sensitivity for relatively large targets can also be decreased.1-4 The purpose of this study was to examine the quantitative relationship between the loss of foveal visual acuity and the reduction in foveal letter contrast sensitivity in subjects with RP in order to provide further information about the nature of the foveal dysfunction. Acuity and contrast sensitivity were assessed both by means of a computerized display system and by commercially available chart tests.
Optic neuritis: small reductions in luminance cause large losses in vision function.
Authors: Schneck M. E. , Haegerström-Portnoy G. , Katz B. , Brabyn J.
Published: February 2023

The SKILL (Smith-Kettlewell Institute Low Luminance) Card was part of a battery of vision tests used to evaluate vision function in eleven 'recovered' optic neuritis patients1. Despite having normal or near normal visual acuity, most individuals showed residual deficits in other vision measures, including reduced color vision, contrast sensitivity, and S and M cone sensitivities. The SKILL Card (Figure 1), proved particularly sensitive, showing all of the 'affected eyes' and most (73%) of the unaffected eyes to be abnormal. In many instances, the loss revealed by the SKILL Card was quite dramatic.
Polarization Instability in a Twisted Optical Fiber
Authors: Feldman Sandra F. , Weinberger Doreen A. , Winful Herbert G.
Published: February 2023

Polarization instabilities in a weakly birefringent optical fiber with low twist lead to experimentally observed modulational gain and asymmetry between the principal fiber axes.
Theory of Bistability and Self-Pulsing in an Optical Ring Circuit Having Saturable Photorefractive Gain, Loss, and Photorefractive Feedback
Authors: Crouch David D. , Lininger Diana M. , Anderson Dana Z.
Published: February 2023

We present a theory for an optical ring circuit in which gain, loss, and feedback are provided by means of refractive-index gratings in photorefractive crystals. Maxwell’s equations and the Kukhtarev charge transport model describe the evolution of the optical fields and the gratings, respectively. Steady-state solutions of the equations exhibit bistability. Dynamic solutions, obtained numerically, exhibit either history-dependent bistability due to the dependence of the feedback coupling element on its past, or self pulsing, depending on the relative speeds of the photorefractive gain and loss.
Systems Based on S-SEEDs and Free-Space Digital Optics
Authors: Hinton H. S.
Published: February 2023

This paper will review the hardware required for photonic switching fabrics and optical computing systems based S-SEED arrays and free-space digital optics. These fabrics are based on diffraction limited optics, regenerative digital logic devices, differential digital signals, 2-D pixelated images, a fan-in and fan-out of two, and single wavelength operation.
Applications of Neural-Network Algorithms to Nonlinear Time Series Analysis of Dynamical Optical Systems
Authors: Bowden C. M. , Hall C. E. , Pethel S. D. , Sung C. C.
Published: February 2023

The techniques of prediction and modeling using a neural network algorithm, preceded by application of noise reduction methods, are shown to be applicable to time series associated with nonlinear dynamical optical systems. The time series generated from a generic dynamical model is used to train a backpropagation, feed forward neural network which is subsequently used to demonstrate strong predictive characteristics. It is demonstrated that such a simple neural network, consisting of fifty neurons, trained using a time series generated from the logistic map in the chaotic regime, produces a self-generated time series which has a maximum positive Lyapunov exponent, χ, which is within six percent of the value obtained from the map, using the same method for determination of χ from the time series. It is also shown that system and measurement noise can be reduced, in the white noise driven logistics map, to within ten percent using an extended Kalman filter algorithm.
Nonlinear Dynamics of Active Mode-Locked Gas Lasers: Model and Experiment
Authors: Melnikov L. A. , Sinichkin U. P. , Tatarkov G. N.
Published: February 2023

We propose a dynamic model of an active mode-locked gas laser and present a detailed experimental investigation of an argon ion laser dynamic behavior. We have drawn the diagrams of dynamic regimes in the parameters planes and have demonstrated some of new regimes of periodic instabilities.
Stable and Dynamical Features of Raman Lasers
Authors: Lu Weiping , Harrison R. G.
Published: February 2023

Analytic analysis establishes bistable and unstable emission from a single mode Raman laser occurring over broad cavity tuning and close to the first lasting threshold. Period doubling routes to chaos prevail for both good and bad cavity conditions.
Dynamics of Nonlinear Systems: Lasers and Superconductors
Authors: Oraevsky A. N.
Published: February 2023

The enhanced mathematical model to be valid for description of complicated nonlinear dynamics of superconductor is proposed.
Multistable Operation Effect on the Low-Frequency Noises in the Delayed Feedback Injection Laser
Authors: Kon M. A. , Rabinovich E. M.
Published: February 2023

In the work the results of experimental and theoretical investigations of the multistable operation effect on the low frequency noises in the delayed optical feedback injection laser are presented.
Fluctuational Transitions and Critical Phenomena in a Noise-Driven Optically Bistable Device
Authors: Dykman M. I. , Golubev G. P. , Golubchenko V. P. , Luchinsky D. G. , Tsuprikov S. V. , Velikovich A. L.
Published: February 2023

Fluctuational transitions between the stable states of a passive optically bistable device have been observed and investigated theoretically and experimentally in the absence of spatial effects (for a lumped-parameter system). The problem of calculation of transition probabilities in dynamical systems driven by weak Gaussian noise has been reduced to logarithmic accuracy to a variational problem which is solved for some types of colored noise. The procedure of the experimental determination of the transition probabilities from the data on transmitted intensity is proposed for the case of a broad-band noise in the intensity of incident radiation. The onset of an extremely narrow peak in the power spectrum of the system in the range of the kinetic phase transition is revealed.
Measurements of Intensity Fluctuations in a Tricritical Laser
Authors: Mortazavi Mansour , Singh Surendra
Published: February 2023

Steady-state intensity fluctuations of the laser with a saturable absorber are studied experimentally in a regime where the leading nonlinearity is of the fifth order in the field amplitude.
Degenerate Optical Parametric Oscillator with a Saturable Absorber
Authors: Ruo-Ding Li , Mandel Paul
Published: February 2023

We consider a degenerate optical parametric oscillator (DOPO). A coherent signal is injected with real amplitude ϵ and phase 2iω0t. The cavity has two resonant modes at frequencies ν1 ≃ ω0 and ν2 ≃ 2ω0. A nonlinear crystal converts photons of frequency ν2 into pairs of photons of frequency ν1 = v2/2. A saturable absorber is inserted in the cavity and can absorb photons at the frequency ν1. The absober is described by a collection of N homogeneously broadened two-level atoms with atomic frequency ω ≃ ω0.
Periodic and Chaotic Operations of a Laser with a Saturable Absorber
Authors: Vladimirov A. G. , Pelyukhova E. B. , Fradkin E. E.
Published: February 2023

We study numerically and analytically the small amplitude periodic solutions of semiclassical equations for a laser with a saturable absorber. We investigate the bifurcation sequence, leading to period-doublings, crises of chaotic attractors, and intermittency.
Information Theoretical Study of Maxwell-Bloch Turbulence
Authors: Ikeda K. , Otsuka K. , Matsumoto K.
Published: February 2023

A wave-number domain information theoretical analysis proposed previously is applied to studying dynamical structures of chaotic multi-mode oscillations exhibited by homogeneously broadened Maxwell- Bloch (M-B) model. Most of radiation energy is concentrated at the gain center, but turbulent disturbances are generated in two off resonant wave- number regions we call Rabi chaotic bands, and they propagate toward other regions in the wave-number space. The analysis further reveals that there is a close interplay between the gain center and the Rabi bands, which yields a ‘chaotic itinerancy’ over the ruins of local chaotic attractors. This phenomenon results in self-induction of mode partition noise and mode hopping, which have been often observed in multi-mode laser oscillations.
Synchronized Chaos in Arrays of Coupled Lasers
Authors: Winful Herbert G. , Rahman Lutfur
Published: February 2023

A subset of lasers in an array of coupled lasers can produce identical, synchronized, chaotic signals. When synchronization fails, spatio-temporal chaos results.
Dynamics and Transverse Effects in Nonlinear Planar Resonators: a Unified Modal Theory
Authors: Haelterman M. , Vitrant G.
Published: February 2023

By means of a new theoretical model we study the influence of transverse effects on the dynamics of nonlinear planar resonators with arbitrary angle of incidence.
Self-Induced Phase Turbulence, Spot Dancing, and Chaotic Itinerancy in Evanescent-Field Coupled Waveguide Lasers
Authors: Otsuka Kenju
Published: February 2023

Spatiotemporal dynamics of coupled nonlinear systems far from thermal equilibrium is an attractive current issue in physics, engineering, chemistry, biology and other fields.1,2 One of the simplest examples is the phase locking probem in two coupled nonlinear oscillators.
Symmetry Breaking and Defect-Mediated Turbulence in Lasers
Authors: Tredicce J. R. , D’Angelo E. J. , Green C. , Mindlin G. B. , Narducci L. M. , Solari H. , Oppo G. L. , Gil L.
Published: February 2023

There is a new issue that needs to be explored which concerns the spatial behavior of optical systems and lasers in particular: are lasers able to display the type of complex spatial structures such as one finds under fully developed turbulence conditions in hydrodynamic systems? Turbulence involves increasing complexity not only in time but also in space; one could argue that, just as dynamical chaos results from the presence of at least a few competing frequencies in a nonlinear system, spatial complexity may be obtained when competing spatial structures play a relevant role in the evolution of a dynamical system.
Diffraction/Diffusion Mediated Instabilities in Self-focusing/Defocusing Nonlinear Amplifying Media
Authors: Jakobsen P.K. , Indik R.A. , Newell A.C. , Moloney J.V.
Published: February 2023

Diffraction of light and diffusion of the nonlinear excitation have been known for some time to profoundly influence the nonlinear response of passive optical feedback systems [1]. More recent work has examined the competition between self-focusing and diffraction in the propagation of light in extended nonlinear amplifying media [2]. New classes of broad stripe semiconductor lasers are currently being developed as high-power coherent light sources for wide ranging applications. Such structures suffer the inevitable problems of multi-transverse mode instabilities which are further complicated by carrier diffusion within the wide gain region. It is to be anticipated therefore that any transversal instabilities may be strongly influenced by material diffusion.
Spontaneous Dressed-State Polarization of a Coupled Atom and Cavity Mode
Authors: Carmichael H. J. , Alsing P.
Published: February 2023

The interaction between two-state atoms and the modes of an optical cavity has been studied extensively over many years; in particular, in connection with lasers and optical bistability. These are dissipative systems, and it has been usual in their study to assume that dissipation rates are, in some sense, large compared with the coupling strength between the atoms and the field. Recent work has shown that interesting new dynamical behavior occurs when this is not so. For example, spontaneous emission linewidths can be altered,1,2 and if the coupling is very strong, an emission line can be split into a pair of resonances identified with the normal- mode frequencies of coupled oscillators describing the atomic polarization and the cavity field.3.4 Altered linewidths and normal-mode splitting are features of weak excitation; both are explained by a coupled damped harmonic oscillator model. In this paper we report new results obtained for strong excitation.
Squeezing Spectrum in Second-Harmonic Generation in the Self-Pulsing Domain
Authors: Pettiaux N. P. , Mandel Paul , Fabre C.
Published: February 2023

We consider the process of second- harmonic generation (SHG) in a cavity that is resonant for both the fundamental and second-harmonic modes. In reduced variables, the system can be written [1] as: where γ is the ratio of the two damping coefficients, Aj= (j=1 or 2) are the scaled fundamental (j=1) or second-harmonic (j=2) mode and E is the scaled pumping field.
Pulsations, Bistability, and Hysteresis in Semiconductor Injection Lasers
Authors: Rivlin L. A.
Published: February 2023

The Routh-Hurwitz analysis of the operation of semiconductor lasers shows all types of dynamic behavior that are essentially in accord with the majority of experimental results.
High-Contrast Multiple Quantum-Well Optical Bistable Device with Integrated Bragg Reflectors
Authors: Sfez B. G. , Oudar J. L. , Michel J. C. , Kuszelewicz R. , Azoulay R.
Published: February 2023

Monolithic bistable microcavities with a GaAs/Al0.3Ga0.7As multiple quantum well active layer and AlAs/Al0.1Ga0.9As Bragg reflectors have been fabricated by metalorganic vapor phase epitaxy. The design of the whole structure is such that a good cavity finesse and a high contrast in the reflective mode are simultaneously obtained. This results in a bistability power threshold of less than 3 mW at 838 nm and a contrast ratio as high as 30:1. A new method is proposed, which allows to measure the nonlinear refractive index in a quasi-continuous regime, and in the operating conditions for bistability. The nonlinear index is shown to saturate at higher power, which evidences the need of a good cavity finesse for such bistable devices. Memory effect is then demonstrated: the sample can stay in either of its two stable states for more than 1 ms without spontaneously switching, and for input pulses as short as 60 ns. Finally we describe two-beam experiments with a new experimental configuration, also in reflection, which allows to mix the two input beams and extract the output beam with an ideal 100% efficiency.
Transient statistics in the switch-on of class B lasers.
Authors: Balle S. , Miguel M. San , Abraham N. B.
Published: February 2023

The transient evolution of the output of a single-mode class B laser (SML) after it is switched-on has been characterized from an experimental point of view by the evolution of the output intensity,[1, 2] both in the linear and non-linear regimes. However, from a theoretical point of view the characterization of the transient statistics of a SML beyond the linear regime has not been considered in detail. [3-5] Nevertheless, it has been possible to analyze both the linear and non-linear regimes for class A lasers,[6] showing that the transient statistics during the non-linear regime constitute a mapping of the transient statistics in the linear regime. In this case, an approximate solution for a switch-on event can be constructed (QDT approximation, [7]) which allows to examine the correspondence between the transient statatistics in both regimes. The main difficulty for a SML arises from the fact that no analytical solution of the deterministic rate equations is known, though it has been shown numerically[3, 4] that the QDT approximation succesfully explains the transient statistics in both the linear and non-linear regimes. Accordingly, we expect that the transient statistics in the non-linear regime can be understood as a mapping of the Passage Time (PT) statistics. The reason is that the random PT t* - defined as the time when the intensity reaches a reference value I
r
– determines both the beginning of a deterministic stage of evolution and the initial conditions for this period,[3-5] which lasts until the vicinity of the asymptotic steady state is reached.
Period-One Oscillation in Chaotic System with Multimodal Mapping
Authors: Liu Yun , Ohtsubo Junji
Published: February 2023

The behavior of chaotic system described by a differential difference equation (DDE) with a low dimensional mapping has been extensively studied.[1,2] However, the details of the dynamic behaviors especially for a multimodal mapping have not yet been fully understood. It is clear that the usual linear stability analysis can not work for this case, since more than two equilibria exist in the dynamics of the system.
Generalised Approach to the Theory of Radiation-Atom Interaction
Authors: Tan Weihan , Lu Weiping , Harrison Robert G.
Published: February 2023

In describing the nonlinear interaction of radiation with matter it is well known that the perturbation expansion technique is used to calculate the atomic wave functions and the transitions between the states of a system. However the technique, though involving all states of the system, is valid only in the limit of weak interaction fields and non-resonant interactions. For strong fields and resonant interactions, density matrix or dressed atom formulisms are commonly used though these exact treatments are restricted to simple two level schemes or approximations of these; their application to general resonant-near resonant multilevel interactions being prohibitively complex.
Nonlinear Dynamics of Ultrashort Pulse Formation
Authors: Speaker to be announced
Published: February 2023

Summary not available at press time.
Modulation Dynamics of a Two-Mode Laser
Authors: Mandel Paul , Georgiou M. , Otsuka Kenju
Published: February 2023

We present new results on the dynamics of solid-state lasers with a few number of modes. Organized collective behavior has been observed in various nonlinear optical systems, suggesting some generic behavior of periodic solutions in multimode lasers [1 - 5]. For instance, antiphase modulation of an N-mode laser is a self-organized collective behavior in which each mode is characterized by N relaxation frequencies ω1< ω2< ω…<ωN, while the total frequency oscillates only at ωN. We have obtained analytic expressions for these frequencies in the N-mode case and we have determined the domain of parameters in which antiphase modulation occurs.
Geometrical phases in self-pulsing lasers
Authors: Ning C.Z. , Haken H.
Published: February 2023

As observed in detuned lasers [1, 2] the arbitrary constant phase of the laser field in the CW region starts to drift linearly besides pulsations in the self-pulsing region. The fact that this drift might have similarities with the Berry phase [3] was pointed out in [2, 4] and a comparative study was given by us [2]. It has been not easy to establish an exact mathematical relation between the two, however. Thus a compelling analogy is still lacking. The main obstacle is that the original formulation [3] of the Berry phase was given for linear Schrodinger systems, whereas we have here an essentially non-linear and dissipative system. Fortunately we have succeeded in borrowing the geometrical formulation of the Berry phase for linear systems [5] and essentially generalizing it to a certain kind of nonlinear dissipative systems, to which detuned one- and two-photon lasers belong. An exact analogy is therefore established. We show that the whole phase accumulation of the laser field in a period of the intensity pulsation consists of two parts: a dynamical part given directly by the equation of movement and a geometrical part given by the path-integral along the trajectory of limit cycles in a certain phase space. This later part has the same origin as that due to parallel transportations of vectors in a curved space.
Nonlinear Dynamics of Photon - Phonon Lasing in Indirect Gap Semiconductors
Authors: Rivlin L.A. , Zadernovsky A.A.
Published: February 2023

We investigate nonlinear dynamics of photon-phonon generation in indirect gap semiconductors with aid of rate equations. Due to intrinsic nonlinearity of the two-quantum transitions one can expect a great variety of operation states for the photon-phonon generation.
Successions of Bifurcations in the Laser with a Saturable Absorber as Distributed System
Authors: Kotomtseva L.A. , Samson A.M.
Published: February 2023

Results of the investigation of the semiclassical equations for the running wave in the laser with a saturable absorber are proposed on the basis of the system for normalized values and sizeless coordinates Here and ei, φi and pi, ψi are the amplitudes and phases of the field and of the polarization of the medium, accordingly, ki is the relative inversion of populations, i=1 for an active medium, i=2 for an absorber. Constants di and gi determine the relaxation rates of the inversion of populations and polarization of the medium, fi. characterizes the distributed losses, ai, bi and h give the efficiency of the interaction of the polarization and inversion of the medium with the field, wc and wai are the frequencies of the cavity and of the medium.
Combination Mode-Mode Coupling as an Instability Mechanism in a Dye Ring Laser
Authors: Ya.I. Khanin , Koryukin I.V.
Published: February 2023

The low-frequency time-dependent processes observed in the spectra of class A and class B lasers (according Arecchi [1]) can’t be explained using the rate equations. However, by introducing other nonlinear processes of mode coupling in addition to the laser medium saturation one gets a deeper insight into the nature of the multimode laser instability. There was a successful attempt in ref. [2] to take into account the influence of mode coupling on laser action via stimulated Brillouin scattering. However, it should be natural to seek for the reason of the nonlinear mode coupling in the laser medium itself. In the next high-order approximation of the dynamical theory of laser with adiabatically eliminated polarization, the combination mode-mode coupling (CMMC) due to the mode- induced inversion oscillations is taken into account [3-5].
Chaotic Behavior Associated with a Multicodimension Bifurcations in a Laser with a Saturable Absorber
Authors: Vladimirov A.G.
Published: February 2023

It has been shown both theoretically and experimentally that a laser with a saturable absorber (LSA) may exhibit various types of chaotic behavior. Theoretical investigations of such behavior in LSA with CO2 amplifying medium has been carried out on the basis of three level : two level rate equation model [1]. In order to improve the agreement between the model and experimental observations the extension of the model including the polarization of molecular absorber has been proposed in Ref.[2]. It has been shown in [2] that a new types of chaotic regimes arise due to the time lag between the polarization and field. Here we show that these chaotic regimes are associated with a codimension- four bifurcation point. We present the detailed investigation of the bifurcation sequences leading to chaotic operations in the vicinity of this point in the case of detuned LSA.
Influence of Velocity-Changing Collisions on Single-mode Inhomogeneously Broadened Laser Dynamics
Authors: Meziane B. , Ladjouze H.
Published: February 2023

The single-mode inhomogeneously broadened [SMIB] laser in the bad cavity configuration has now become a classic example in the demonstration of low-excitation instabilities in nonlinear systems. The general theoretical models in terms of integro-differential "Maxwell-Bloch" equations have for long been shown to be quantitatively accurate for the description of spontaneous pulsations, experimentally obtained in high-gain lasers such as the He-Xe[1,2]. In terms of dynamical aspects these equations are, because of a polarization integral, of infinitely high dimensions, rendering the physics of the behavior rather inscrutable. Recently we have constructed a much more tractable model which consists of only 6 differential equations, yet its deep numerical investigation has shown a one to one qualitative analogy with the infinite-D set of equations in a large range of values of the various control parameters [3]. The simplicity of our model resulted in the clarification of much of the physical insight connected with SMIB laser dynamics.
Optical Bistabilities and Autostabilization of the Solid-State Ring Laser Generation Regimes under Colliding USPs Dynamic Self-Diffraction
Authors: Shelaev A. N.
Published: February 2023

Summary not available.
Coexistence of Two Attractors in Lasers with Incoherent Delayed Feedback
Authors: Otsuka Kenju , Chern Jyh-Long
Published: February 2023

Delay-induced complex dynamics in lasers have been investigated in various schemes, such as rich phenomena, in semiconductor lasers with external feedback,1 and quasiperiodicity in CO2 lasers with electro-optic feedback.2 Recently, we proposed high-speed picosecond pulse generation in semiconductor lasers with incoherent delayed feedback.3 The basic idea was derived from successive carrier modulation by delayed feedback light whose polarization direction is rotated to be orthogonal to the lasing light. Such a feedback scheme is referred to as incoherent feedback.4 We showed theoretically that periodic spiking oscillations can be excited in a short-delay regime, i. e., delay time ≪ carrier lifetime. In this paper, we extend this scheme to general class-B lasers and investigate dynamics in wide parameter regions.
Nonlocal Adiabatic Elimination in the Maxwell-Bloch Equation
Authors: Ru P. , Jakobsen P.K. , Moloney J.V.
Published: February 2023

Adiabatic elimination is a standard procedure applied to the Maxwell-Bloch laser equations when one variable or more is slaved to the remaining variables. An important case in point is a laser with an extremely large gain bandwidth satisfying the condition γ⊥ ≫ γ||, k where γ⊥ is the polarization dephasing rate, γ|| the de-energization rate and k the cavity damping constant. For example, color center gain media satisfy this criterion and support hundreds of thousands of longitudinal modes in synchronous pumped mode-locking operation. For simple single mode plane wave models the crude adiabatic elimination step of setting the derivative of the polarization variable to zero can be avoided by using center manifold techniques [1]. In this general class of singular perturbation problem, the idea is to coordinatize the problem using linear stability analysis about some known solution and then to construct an approximation to the center manifold on which the (possibly dynamic) solution remains for all time. This procedure has been successfully applied to the Maxwell-Bloch equations describing a single mode homogenously broadened ring laser [2]. Extension of the procedure to nonlinear partial differential equations is very difficult in general as the resulting center manifold may be an infinite dimensional object. When transverse (or additional longitudinal) degrees of freedom are introduced in the Maxwell-Bloch equations in order to investigate spatial pattern formation (or mode-locking dynamics) we find that a crude adiabatic elimination (henceforth referred to as standard adiabatic elimination SAE) leads to nonphysical high transverse (or longitudinal) spatial wavenumber instabilities [3]. Recent attempts to apply the center manifold technique to the transverse problem have met with mixed success [4]. In fact the high transverse wavenumber instability shows an even stronger divergence than the SAE case for positive sign of the laser-atom detuning. Moreover, the analysis becomes unwieldy even in situations when the center manifold approach appears to work.
Pulse Pattern Selection and Low Dimensional Modulational Chaos in Fiber Lasers
Authors: Haelterman M. , Trillo S. , Wabnitz S.
Published: February 2023

In this work we analyse the process of generation and control of stable or chaotic soliton pulse trains in ultrashort pulse fiber lasers. We reveal the underlying low dimensional homoclinic structure of the nonlinear modulational instability (MI) in a cavity. The onset of spatiotemporal structures in physical systems may often be described in terms of reduced modal expansions which preserve the complexity of the original infinite dimensional model [1]. The advantage of such a reduction procedure is that the transition to chaos may be traced back to the universal bifurcation routes of finite dimensional dynamical systems.
Two Dimensional Analysis on Nonlinear Interferometer and Decay of Spirals
Authors: Adachihara H. , Faid H.
Published: February 2023

Our two dimensional analysis on Vorontsov’s nonlinear interferometer model reveals how to construct complex patterns with unstable eigenmodes and how spirals decay into petals.
Collapse of a Transverse Mode Continuum in a Photorefractive Oscillator
Authors: Saffman Mark , Montgomery Don , Anderson Dana Z.
Published: February 2023

The transverse field profile in oscillators with nonliinear media is determined by the interplay between the nonlinearity and the resonator geometry. In typical laser resonators the resulting field is a superposition of low order Hermite-Gaussian modes. However, there are some oscillator geometries, such as the self-imaging ring resonator[1],which do not lead to a well defined transverse mode. Since any optical ray is imaged back onto itself after one cavity round trip, there is no preferred optical axis. Diffraction effects will lead inevitably to high losses for rays which propagate far from the optical axis, however, there still exist a large number of possible modes, all with very similar losses. In this paper we show how to actively define the optical axis in such a self-imaging resonator by placing saturable photorefractive gain and loss nonlinearities in conjugate resonator planes. The transverse profile maximizes the oscillating power by saturating the photorefractive gain as little as possible, and saturating the photorefractive loss as much as possible. The resulting transverse mode turns out to be highly localized, but with an arbitrary axis of propagation inside the resonator.
Dynamic Instability in Delay-Coupled Semiconductor Lasers
Authors: Bossert David J. , DeFreez Richard K. , Dente Gregory C. , Winful Herbert G.
Published: February 2023

Although semiconductor lasers are inherently large-linewidth and low-power devices, these limitations can be overcome by coupling their output to another laser or resonator. A coupling delay, however, is known to cause an extreme loss of coherence for a self-coupled diode laser above a critical coupling level.1 Unstable operation has also been observed recently in a system of two semiconductor lasers mutually coupled at a distance,2 a phenomenon referred to as overcoupling. In this paper, systematic spectral and coherence measurements are described for a single, self-coupled diode laser and two mutually coupled lasers, demonstrating extreme dynamic instability at moderate coupling levels.
The modulated semiconductor laser: a Hamiltonian search for its periodic attractors
Authors: De Jagher P. C. , Lenstra D.
Published: February 2023

Modulated lasers have been investigated for over a decade now, c.f. ref. [3] and references cited therein. Periodic as well as chaotic types of operation have been observed. In this paper we put forward a mathematical technique to calculate lower and upper bounds for the modulation strength which is needed to sustain a periodic large amplitude output.
Chaos in Semiconductor Lasers
Authors: Li Hua , Ye Jun , McInerney John G.
Published: February 2023

Semiconductor lasers are typical class-B lasers in which the decay rates obey γp, γ ≪ γ , where γp, γ . and γ are the decay rates of the photons, population inversion and polarization, respectively. Therefore an isolated semiconductor laser is well described by rate equations with only two independent variables (photon number and carrier population) so that chaos is not observed. Here we show two different geometries to make chaos feasible in a semiconductor laser system. The results clearly demanstrate the origin of instability in the semiconductor laser: the interaction in the nonlinear laser medium between undamped relaxation oscillation (which expresses the energy exchange between carrier population and photons) and some external modulation (which may include optical feedback).
Coherence and Phase Dynamics of Spatially Coupled Solid State Lasers
Authors: Fabiny Larry , Colet Pere , Roy Rajarshi
Published: February 2023

Although coherence properties of semiconductor laser arrays have been the subject of extensive investigations for many years [1], solid state laser arrays are only recently receiving much interest. The two systems are described by similar dynamical equations, but the solid state laser dynamics occur on much slower time scales. In addition, spatial coupling is varied more easily in a solid state array. The solid state array then presents some advantages as a tool in investigating coupled dynamical systems. In this paper we study the coherence properties of two spatially coupled Nd:YAG lasers.
Coupled elements, phase transitions and localized order
Authors: McCall Martin , Jiang Ziping
Published: February 2023

Two-dimensional optoelectronic device arrays have considerable potential for applications ranging from the production of high power coherent beams (i.e. 2D laser arrays) to processing based on multichannel optical interconnects in neural computation. It is quite clear, however, that modeling such complex systems with various inter-element coupling schemes is not an easy task.
Controlling Laser Chaos
Authors: Bielawski S. , Bouazzaoui M. , Derozier D. , Glorieux P.
Published: February 2023

In 1990 Ott, Grebogi and Yorke described an attractive method (OGY) whereby small time-dependent perturbation applied to a chaotic system allowed to stabilize unstable periodic orbits[1]. This method is applicable to experimental situations in which a priori analytical knowledge of the system is not available[2,3]. Their method assumes the dynamics of the system can be represented as arising from a nonlinear map (e.g., a return map). The iterates are then given by Xn+1 = F(Xn,p), where p is some accessible parameter of the system. To control chaotic dynamics one only needs to learn the local dynamics around the desired unstable periodic orbit (e.g., a fixed point Xn=XF) on the nonlinear map : especially, the derivatives with respect to p of the orbit location. When the motion is near the periodic orbit(Xn#XF), small appropriate temporal perturbations of the control parameter p allow to hold the motion on its unstable periodic orbits.
Dynamics of passive FM locking in semiconductor lasers
Authors: Shore K.A. , Yee W.M.
Published: February 2023

In earlier work [1] the role of gain nonlinearities in effecting self-locked FM supermode oscillation in semiconductor lasers was established and the requisite gain saturation and multiwave mixing nonlinearities were shown to be consistent with the experimental observations of Tiemeijer et al [2]. A three-mode laser model is sufficient to demonstrate the occurrence of intrinsic FM locking in semiconductor lasers but, in order, for example, to calculate the depth of FM modulation in the self-locked state a multimode model is required. In the present work the model of [1] has been extended to take more than three modes into account.
Bifurcation Analysis of Bistable Systems Disturbed by External Noise: an Application of Cumulant Analysis
Authors: Anischenko V. S. , Neiman A. B.
Published: February 2023

Summary not available at press time.
Hexagonal Transverse Patterns in the Counter-Propagated Light Beams Interaction: Many-Body Approach
Authors: Afanas'ev A.A. , Samson B.A. , Volkov V.M.
Published: February 2023

The hexagonal patterns in nonlinear optics previously have been discovered experimentally [1,2] and numerically [3]. It was noted that the appearance of the hexagons is one of the displaying of strong counter-propagated light beams instability, in particular, in the media with Kerr-like nonlinearity.
Squeezing in Wide-Aperture Nonlinear Interferometer: Transverse Effects
Authors: Belinsky A.V. , Rosanov N.N.
Published: February 2023

Fluctuations of radiation and of photodetector current present a fundamental limit for capabilities of parallel optical processing. In this connection it seems perspective to use the light squeezed states to depress photon noise of optical images. In this report we consider a possibility of generation of sufficiently wide (multi-mode) beams of sub-Poisson light transmitting coherent radiation through wide-aperture nonlinear interferometer.
Theory of a Photorefractive Resonator
Authors: Zeghlache H. , Dambly L. , Glorieux P.
Published: February 2023

A theory of the two-wave mixing in a photorefractive medium placed in a ring cavity is developped following the model first derived by Yariv and Kwong [1]: a steady refractive index involving the photorefractive effect is used as a non-linear source-term (PNL) in the Maxwell equations, and the cavity field is expanded on the transverse cavity modes. In this model we take into account the intensity change of both the pump and resonator beams inside the crystal due to the mutual power exchange: we have developed a multimode model which gives in the long-time limit the z-dependance of the fields (z is the optical axis) for a passage in the crystal, using the expansion in terms of the complete set of the cavity transverse modes. [2]
Rössler Chaos in Opto-Thermal Bistability with Localized Absorption
Authors: Herrero Ramon , Boixader Francesc , Orriols Gaspar , Roseli Joan I. , Pi Francesc
Published: February 2023

We present numerical and experimental evidences of Rössler chaos in the response of BOITAL trilayer systems. BOITAL devices are opto-thermal bistable cavities in which the absorption occurs localized in the input mirror and the spacer is made of transparent thermo optic materials [1]. In the case of multilayer spacers of alternatively opposite thermo-optic materials, the competing phase-shift contributions of the various layers are affected by different time delays according to the relative position with respect to the localized heat source and, in this way, it is possible to have self-sustained oscillations and other sorts of instabilities in the response of the system [2-4]. A remarkable feature in the dynamics of such systems is the fact that their effective dimension is determined by the number of layers in the spacer and, therefore, they permit the analysis of gradual complexity [6]. Another remarkable features are the easy occurrence of homoclinic bifurcations in their response and the really good agreement between experiments and numerical simulation by integration of either the corresponding partial differential equations or a simplified ODE’s model of order equal to the number of layers [6].
Pulse statistics of modulated gas lasers
Authors: Valle A. , Pesquera L. , Rodríguez M. A.
Published: February 2023

Pulse statistics of modulated class A single mode lasers is analyzed both numerically and analytically. The time evolution of the electric field is described by the following equation where a is the pump parameter and ψ is the spontaneous emission noise of intensity D. An analytic approximation is developed for the switch-on time probability density. In this approximation the time evolution is divided in two regimes: a linear one with noise, where saturation is not important, and a nonlinear deterministic domain. Using a kind of self-consistency condition for the switch–on time probability density P(t), an integral equation is derived for P(t). Numerical simulations show that this approximation is very accurate (see Fig.1).
Patterns and Their Defects
Authors: Coullet Pierre
Published: February 2023

Summary not available at press time.
Pattern Formation and Pattern Dynamics in Passive Systems
Authors: Brambilla M. , Castelli F. , Gatti A. , Lugiato L. A. , Prati F.
Published: February 2023

The theoretical modeling and systematic investigation of the transverse effects, due to diffractive phenomena in the propagation of electric fields in nonlinear optical systems, have recently received increasing interest, for both passive and laser systems1,2.