Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Quantum Electronics

Threshold conditions for generation in a photorefractive crystal with counterpropagating mutually incoherent pump beams

Mikhail V. Vasnetsov, A. V. Il'Enkov, S. G. Odulov, M. S. Soskin

Published Mar 31, 1993• 0 citations
Publisher

Abstract

The threshold conditions for generation are found for media with a nonlinear response of a mixed type. The possibility of cavity-free generation in a photorefractive crystal with a purely local initial response, by virtue of a shift of the generation frequency away from the pump frequency, is analyzed. The frequency shift and the wave-vector mismatch are derived as a function of the interaction constant.

DOI
10.1070/qe1993v023n03abeh002979

Related papers

Transverse instability threshold in counterpropagating light beams for a nonlinear medium with local photorefractive response

Boris I. Sturman, Alexander I. Chernykh

We derive the threshold conditions for the instability of counterpropagating waves in a nonlinear medium with local photorefractive response against the excitation of transverse small-angle structures. These conditions allow for all the important types of diffraction from refractive-index reflection gratings and are not limited to the case of strict frequency degeneracy of the waves. We study the dependence of the crystal-thickness threshold and the secondary wave emission angle on the crystal parameters and the pump conditions. We show that when the pump wave intensities differ considerably, excitation of standing light structures is replaced by excitation of traveling structures. Finally, we discuss the applications of the theory to experiments with the photorefractive crystals LiNbO 3 and LiTaO 3 .

Journal of Experimental and Theoretical Physics•May 1, 1997•1 citation

Parametric Oscillation in Photorefractive Crystals with Local Response in Unclosed Optical Cavities

Adam Mazur, A. D. Novikov, S. G. Odulov +1 more

Steady-state coherent oscillation in the ring-loop and double-side mirror geometries is first observed and studied in media with local nonlinear response. The results of calculation are presented stating that the oscillation becomes possible providing two necessary conditions are met: the oscillation waves appear 1) misaligned with respect to strictly backward to pumps directions to restore the phase matching, and 2) they are shifted in frequency with respect to the pump waves. By appropriate choice of frequencies of two incident waves in double-side mirror geometry one of oscillating waves may be done a perfect conjugate replica of an input wave with limited spatial spectrum.

Photorefractive Effects, Materials, and Devices•Jan 1, 1991•0 citations

Frequency shift in an oscillator with photorefractive gain

Laurent Dambly, H. Zeghlache

A self-consistent theory is used to derive the frequency shift presented by the oscillating mode in a cavity that contains a photorefractive crystal. A long-time-limit theory has been used to get the steady characteristics of the cavity field. The problem of the weak-field approximation is avoided. This approximation is useless in the case studied because the interaction along the crystal is so strong that one has to take in account the intensity exchange occurring inside the material between the pump and oscillating beams (two-wave mixing). We have fully analyzed the influence of the transverse nature of the beams on the intensity exchange in the two-wave mixing situation. In the photorefractive resonator case, the frequency shift of the oscillating beam is expressed in terms of a ratio that presents poles. The dependence on the problem parameters of these poles is studied and a perturbative method is developed; it is based on the smallness of the transverse overlap between the pump and cavity modes. An analytical expression for this frequency shift is obtained.

Physical Review A•Mar 1, 1993•15 citations

Instability of almost opposite mutually noncoherent waves in nonlinear media with a local transient response

A. V. Mamaev, Vladimir V. Shkunov

The instability thresholds were found for almost opposite waves whose interference pattern could not be recorded by a medium utilizing a transient optical nonlinearity of the local type. Pairs of waves with an angular shift relative to the direction opposite to the pump radiation were generated.

Soviet Journal of Quantum Electronics•Mar 31, 1991•0 citations

Phase conjugation involving incoherent counterpropagating beams in photorefractive media

Mordechai Segev, Amnon Yariv

We propose and analyze a new type of phase conjugation between counterpropagating beams in photorefractive materials based on diffraction from transmission gratings only. This effect does not require temporal coherence between the counterpropagating beams and may occur spontaneously, with no external seeding, even with wide (frequency) band light sources.

Optics Letters•Dec 15, 1991•15 citations

Optical bistability by photorefractive two-wave mixing

Jianquan Yao, J. Wang

It is known that two-wave coupling in photorefractive crystal may result in an intensity-dependent phase shift as well as energy transfer between the two waves without phase crosstalk. In a sense, this kind of phase shift is similar to the intensity-dependent refractive-index effects in Kerr media. Consequently, optical bistability can be established in an optical cavity with a photorefractive crystal. We formulate the model and get the expected bistable transmission with numerical simulations. Several cases, including that of the codirectional coupling and the contradirectional coupling, are considered. The effects of the photorefractive crystal’s distribution absorption and the spatial phase shift between the index grating and the light interference pattern in the crystal on the nonlinear transmission characteristics have also been studied. It is interesting to note that the output of the pumping wave is dependent on the cavity intensity and thus shows bistable behavior with respect to the cavity input as well.

Annual Meeting Optical Society of America•Jan 1, 1987•0 citations
The threshold conditions for generation are found for media with a nonlinear response of a mixed type. The possibility of cavity-free generation in a photorefractive crystal with a purely local initial response, by virtue of a shift of the generation frequency away from the pump frequency, is analyzed. The frequency shift and the wave-vector mismatch are derived as a function of the interaction constant.
We derive the threshold conditions for the instability of counterpropagating waves in a nonlinear medium with local photorefractive response against the excitation of transverse small-angle structures. These conditions allow for all the important types of diffraction from refractive-index reflection gratings and are not limited to the case of strict frequency degeneracy of the waves. We study the dependence of the crystal-thickness threshold and the secondary wave emission angle on the crystal parameters and the pump conditions. We show that when the pump wave intensities differ considerably, excitation of standing light structures is replaced by excitation of traveling structures. Finally, we discuss the applications of the theory to experiments with the photorefractive crystals LiNbO 3 and LiTaO 3 .
Steady-state coherent oscillation in the ring-loop and double-side mirror geometries is first observed and studied in media with local nonlinear response. The results of calculation are presented stating that the oscillation becomes possible providing two necessary conditions are met: the oscillation waves appear 1) misaligned with respect to strictly backward to pumps directions to restore the phase matching, and 2) they are shifted in frequency with respect to the pump waves. By appropriate choice of frequencies of two incident waves in double-side mirror geometry one of oscillating waves may be done a perfect conjugate replica of an input wave with limited spatial spectrum.
A self-consistent theory is used to derive the frequency shift presented by the oscillating mode in a cavity that contains a photorefractive crystal. A long-time-limit theory has been used to get the steady characteristics of the cavity field. The problem of the weak-field approximation is avoided. This approximation is useless in the case studied because the interaction along the crystal is so strong that one has to take in account the intensity exchange occurring inside the material between the pump and oscillating beams (two-wave mixing). We have fully analyzed the influence of the transverse nature of the beams on the intensity exchange in the two-wave mixing situation. In the photorefractive resonator case, the frequency shift of the oscillating beam is expressed in terms of a ratio that presents poles. The dependence on the problem parameters of these poles is studied and a perturbative method is developed; it is based on the smallness of the transverse overlap between the pump and cavity modes. An analytical expression for this frequency shift is obtained.
It is known that two-wave coupling in photorefractive crystal may result in an intensity-dependent phase shift as well as energy transfer between the two waves without phase crosstalk. In a sense, this kind of phase shift is similar to the intensity-dependent refractive-index effects in Kerr media. Consequently, optical bistability can be established in an optical cavity with a photorefractive crystal. We formulate the model and get the expected bistable transmission with numerical simulations. Several cases, including that of the codirectional coupling and the contradirectional coupling, are considered. The effects of the photorefractive crystal’s distribution absorption and the spatial phase shift between the index grating and the light interference pattern in the crystal on the nonlinear transmission characteristics have also been studied. It is interesting to note that the output of the pumping wave is dependent on the cavity intensity and thus shows bistable behavior with respect to the cavity input as well.