Spatiotemporal structures in the internally pumped optical parametric oscillator (original) (raw)
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Optics Letters, 2000
We analyze pattern formation in doubly resonant intracavity second-harmonic generation in the presence of competing nondegenerate parametric downconversion. We show that for positive cavity detuning of the fundamental frequency the threshold for parametric oscillation is lower than that of transverse, pattern forming instabilities. The parametric oscillation strongly modif ies the pattern dynamics found previously in a simplif ied analysis that neglects parametric instability [Phys. Rev. E 56, 4803 (1997)]. Stationary and dynamic patterns in the presence of parametric oscillation are found numerically.
Physical Review A, 1999
We theoretically investigate the generation of spatial patterns in intracavity second-harmonic generation. We consider a cavity with planar mirrors that is resonant at the fundamental frequency, but not at the secondharmonic frequency. A mean-field model is derived that describes the resonant fundamental field, and its coupling to a pair of nondegenerate parametric fields. The parametric fields are driven by the nonresonant second-harmonic field. Analysis indicates the existence of transverse instability of the pump field alone, as well as the possibility of simultaneous instability of the pump and the parametric fields. A range of spatial structures including periodic planforms as well as spatially localized states are found numerically. The simplicity of the singly resonant cavity makes it well suited for experimental studies. Estimates of experimental parameters necessary for observation of spatial structures are given. ͓S1050-2947͑99͒02810-3͔
Physical Review A, 2002
We predict and experimentally observe temporal self-pulsing in singly resonant intracavity second-harmonic generation under conditions of simultaneous parametric oscillation. The threshold for self-pulsing as a function of cavity tuning and phase mismatch are found from analysis of a three-component mean-field model. Analytical mean-field calculations of the self-pulsing frequency as well as numerical simulations including the effects of a time-dependent pump pulse agree with the experimentally observed frequencies.
Temporal Simultons in Optical Parametric Oscillators
Physical review letters, 2018
We report the first demonstration of a regime of operation in optical parametric oscillators (OPOs), in which the formation of temporal simultons produces stable femtosecond half-harmonic pulses. Simultons are simultaneous bright-dark solitons of a signal field at frequency ω and the pump field at 2ω, which form in a quadratic nonlinear medium. The formation of simultons in an OPO is due to the interplay of nonlinear pulse acceleration with the timing mismatch between the pump repetition period and the cold-cavity round-trip time and is evidenced by sech^{2} spectra with broad instantaneous bandwidths when the resonator is detuned to a slightly longer round-trip time than the pump repetition period. We provide a theoretical description of an OPO operating in a regime dominated by these dynamics, observe the distinct features of simulton formation in an experiment, and verify our results with numerical simulations. These results represent a new regime of operation in nonlinear resona...
Spiral Intensity Patterns in the Internally Pumped Optical Parametric Oscillator
Physical Review Letters, 2000
We describe a nonlinear optical system that supports spiral pattern solutions in the field intensity. This new spatial structure is found to bifurcate above a secondary instability in the internally pumped optical parametric oscillator. The analytical predictions of threshold and spatial scale for the instability are supplemented by detailed numerical investigations of the formation of spiral patterns.
Physical Review A, 2013
Spatio-temporal dynamics of singly resonant optical parametric oscillators with external seeding displays hexagonal, roll and honeycomb patterns, optical turbulence, rogue waves and cavity solitons. We derive appropriate mean-field equations with a sinc 2 nonlinearity and demonstrate that offresonance seeding is necessary and responsible for the formation of complex spatial structures via selforganization. We compare this model with those derived close to the threshold of signal generation and find that back-conversion of signal and idler photons is responsible for multiple regions of spatio-temporal self-organization when increasing the power of the pump field.
Optical-parametric-oscillator solitons driven by the third harmonic
Physical Review E, 2004
We introduce a model of a lossy second-harmonic-generating (χ (2) ) cavity externally pumped at the third harmonic, which gives rise to driving terms of a new type, corresponding to a cross-parametric gain. The equation for the fundamental-frequency (FF) wave may also contain a quadratic self-driving term, which is generated by the cubic nonlinearity of the medium. Unlike previously studied phase-matched models of χ (2) cavities driven at the second harmonic (SH) or at FF, the present one admits an exact analytical solution for the soliton, at a special value of the gain parameter. Two families of solitons are found in a numerical form, and their stability area is identified through numerical computation of the perturbation eigenvalues (stability of the zero solution, which is a necessary condition for the soliton's stability, is investigated in an analytical form). One family is a continuation of the special analytical solution. At given values of parameters, one soliton is stable and the other one is not; they swap their stability at a critical value of the mismatch parameter. The stability of the solitons is also verified in direct simulations, which demonstrate that the unstable pulse rearranges itself into the stable one, or into a delocalized state, or decays to zero. A soliton which was given an initial boost C starts to move but quickly comes to a halt, if the boost is smaller than a critical value C cr . If C > C cr , the boost destroys the soliton (sometimes, through splitting into two secondary pulses). Interactions between initially separated solitons are investigated too. It is concluded that stable solitons always merge into a single one. In the system with weak loss, it appears in a vibrating form, slowly relaxing to the static shape. With stronger loss, the final soliton emerges in the stationary form.
Fast oscillations in an optical parametric oscillator
Optics Communications, 2001
We report on the observation of fast oscillations at frequencies of a few MHz in a triply resonant optical parametric oscillator. These oscillations can appear alone, or superimposed on slow oscillations due to thermo-optical instabilities, and display a great variety of waveforms. The analysis of the regimes observed experimentally leads us to conjecture that the mechanism responsible for this instability is not the Hopf bifurcation of the single-mode mean-®eld model, but that it is based on the interaction of two signal ®elds oscillating in cavity modes with neighboring frequencies. This interpretation is supported by numerical simulations of the mean-®eld model with two coupled modes, which reproduce well the behaviors observed experimentally. We also ®nd chaotic solutions of this model, which unveils another possible scenario leading to deterministic chaos in this system. Ó
Internal optical parametric oscillation
IEEE Journal of Quantum Electronics, 1971
The theory of optical parametric oscillation internal to the laser cavity is extended to include the dynamics of the population inversion of the laser medium, thus generalizing it to include all laser-oscillator systems. The equations of motion of the .oscillator-laser system are solved by digital computer for the case of a &-switched Nd:YAG laser with a LiNb03 parametric oscillator inside the laser cavity. It is found that this internal optical parametric oscillator operates in a spiking regime, with one or more oscillator pulses per pump pulse. The oscillator pulses inside the nonlinear crystal are often more intense than the laser pulse that would have existed in the absence of parametric oscillation. Oscillator pulse lengths are much shorter than the laser pulse length, with oscillator pulse lengths of typically 5-10 ns compared to laser pulse lengths of 200 ns. The repetition rate of the oscillator pulses is pump-power dependent, with the pulses occurring more frequently as the laser field increases. The theoretical results are compared with experiment, and the analysis is found to provide a good qualitative description of the &-switched parametric oscillator.