Phase Conjugation Techniques

Concetto R. Giuliano, David A. Rockwell

Gaohang He

A.M. Scott, D. C. Jones, Kevin D. Ridley +1 more

We describe investigations into the conjugation of weak signals, corresponding to a few photons. We have used a variety of techniques, combining various methods of Brillouin amplification and phase conjugation with a laser pre-amplifier. Four Brillouin phase conjugation techniques were used to amplify or conjugate the signal, and in the case of amplification the conjugate can then be generated using conventional SBS.

Boris Ya Zel'dovich, Nikolai F. Pilipetsky, Vladimir V. Shkunov

V E Sherstobitov, Andrey Yu. Rodionov

To the best of our knowledge, a novel self-phase-conjugation technique for laser radiation is proposed, which is based on the self-filtration of the phase-conjugate component in a nonlinear absorbing medium, bleached by a pump wave with the intricate spatial structure in the region of location of its speckles. Similar to the stimulated Brillouin scattering (SBS) case, the mechanism of the phase-conjugate wave discrimination against the noise background is based on the coincidence of the speckles in the pump and conjugate waves throughout the bulk of the medium. To compensate for a drop in the signal power due to total absorption, the amplification in conventional laser gain cells is used. The feasibility of the phase conjugation with reflectivities from unity to tens of percent is demonstrated by analytical estimates and numerical calculations. The technique can find application in the middle and far IR spectral regions, where the implementation of phase conjugation via SBS is either hindered or impossible at all.

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.