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Incoherent phase-conjugate backscattering in photorefractive media

Mordechai Segev, Amnon Yariv

Phase-conjugate backscattering in photorefractive (PR) materials, which can be considered a special case of two-beam coupling, involves interaction between two counterpropagating beams via light-induced reflection gratings. Since this backscattering results from interference between the beams, it requires mutual temporal coherence. Moreover, when one beam is self-generated, the input beam is required to have a long coherence length.

Annual Meeting Optical Society of AmericaJan 1, 19910 citations

Conjugation of Mutually-Incoherent Light Beams in the Geometry of Two Interconnected Ring Mirrors

Aleksei A. Zozulya, A.V. Mamaev

New geometry for conjugation of mutually-incoherent light beams in photorefractive media is proposed. This geometry is realized experimentally and its theoretical description is given. Comparison between theory and experiment is made.

Photorefractive Effects, Materials, and DevicesJan 1, 19900 citations

Mutual phase conjugation of temporally nonoverlapping optical beams

С. А. Корольков, A. V. Mamaev, Vladimir V. Shkunov

It was demonstrated that holographic gratings could be formed by temporally nonoverlapping optical beams. Effects involving coherent erasure by an individual pulse must be small to achieve efficient grating formation.

Soviet Journal of Quantum ElectronicsSep 30, 19923 citations

Observation of harmonic phase conjugation in a photorefractive medium

Tallis Y. Chang, Pochi Yeh

We demonstrate for the first time, to our knowledge, second harmonic optical phase conjugation, using the second spatial harmonics of a nonsinusoidal grating formed in a photorefractive material. The possibility of harmonic phase conjugation has been considered previously for artificial Kerr media.1 We have applied the same idea to barium titanate, since the existence of the higher-order gratings in this material has been known to us for some time. In our experiment, two 1.06-µm cw Nd:YAG laser beams wrote a grating in a poled photorefractive barium titanate crystal. Then a second harmonic of the YAG at 0.532 µm read out the grating in a counterpropagating direction to one of the writing beams. In this geometry, the usual Bragg condition is not satisfied. The reflectivity of the 0.532-µm signal was rather weak, ~0.01%, with ~0.1-mW reading beam power. The buildup time was around 3 s, with loosely focused writing beams with 50-mW power in each beam. The same experiment with a SBN crystal showed no significant harmonic phase conjugation. Finally, we stress that this effect is different from the previously published result.2We demonstrate for the first time, to our knowledge, second harmonic optical phase conjugation, using the second spatial harmonics of a nonsinusoidal grating formed in a photorefractive material. The possibility of harmonic phase conjugation has been considered previously for artificial Kerr media.1 We have applied the same idea to barium titanate, since the existence of the higher-order gratings in this material has been known to us for some time. In our experiment, two 1.06-µm cw Nd:YAG laser beams wrote a grating in a poled photorefractive barium titanate crystal. Then a second harmonic of the YAG at 0.532 µm read out the grating in a counterpropagating direction to one of the writing beams. In this geometry, the usual Bragg condition is not satisfied. The reflectivity of the 0.532-µm signal was rather weak, ~0.01%, with ~0.1-mW reading beam power. The buildup time was around 3 s, with loosely focused writing beams with 50-mW power in each beam. The same experiment with a SBN crystal showed no significant harmonic phase conjugation. Finally, we stress that this effect is different from the previously published result.2

Annual Meeting Optical Society of AmericaJan 1, 19860 citations

Phase conjugation of mutually incoherent light beams in a photorefractive medium

A. A. Zozulya, A. V. Mamaev

Journal of Experimental and Theoretical PhysicsJan 1, 19900 citations

Optical Phase Conjugation and Image Reconstruction.

Hui‐Tian Wang

We review the concept and generation methods of phase conjugate waves. They are particularly emphasizedon optical phase conjugation with the photorefractive effects. Applications of phase conjugation are describedand methods of distorted image reconstruction in one-way image transmission, using both phase conjugationand photorefractive incoherent-to-coherent conversion techniques, are highlighted.

The Review of Laser EngineeringJan 1, 19990 citations

Phase conjugation involving incoherent counterpropagating beams in photorefractive media

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Phase conjugation involving incoherent counterpropagating beams in photorefractive media

Abstract

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