Abstract

It has been theoretically proven that in most situations optical waves, which experience random scattering in a lossless medium, can be completely recovered when reflected by a phase-conjugate mirror. The recovery is not complete, however, if the medium has loss (gain) or if the phase-conjugate mirror changes the wave intensity. When the medium includes random fluctuations of refractive index, such as is brought about by turbulence, the recovery of optical wave deteriorates. The existence of random fluctuations of refractive index in the propagating medium implies random fluctuations of the medium's absorption (emission) according to the Kramers–Kronig relations. In this research, the extent of wave recovery by a phase conjugate mirror in a random medium with loss (gain) is investigated. The wave is propagated through a random medium, reflected by a phase-conjugate mirror, and then propagated back through the same random medium. Because a random system is under investigation, statistical parameters such as average wave field, average intensity, standard deviation of phase, and contrast (scintillation index) are evaluated. These parameters indicate the extent of wave recovery. The Rytov approximation is used, and the planewave assumption is made for mathematical simplicity.

© 1990 Optical Society of America