Phase conjugation

About: Phase conjugation is a research topic. Over the lifetime, 3694 publications have been published within this topic receiving 49099 citations.

Phase conjugation to upgrade efficiency of solid-state-laser energy conversion to narrow-band TEM/sub 00/ mode pulses

Abstract: The possibility of increasing the radiation energy extraction from active elements of YAG:Nd lasers using an oscillator combined with a double-pass amplifier, as well as a four-pass scheme, is shown. >

Supercritical parametric wave phase conjugation as an instrument for narrowband analysis in ultrasonic harmonic imaging

Abstract: Supercritical parametric wave phase conjugation (SWPC) is used for selection and phase conjugation of harmonic components of a nonlinear incident wave. The amplitude of the phase conjugate wave in a supercritical mode is high enough for acoustic nonlinearity of the propagation medium to appear. As a result, in particular, doubled and quadrupled frequencies of the incident wave become available for image formation at the same order of the medium nonlinearity. The improvement of the imaging system resolution because of harmonic analysis of the received acoustic signal and compensation of phase distortions caused by wave phase conjugation were observed simultaneously when the propagation medium was inhomogeneous.

Method and apparatus for control of phase conjugation cells

Abstract: A technique in which one or more phase conjugation cells, such as stimulated Brillouin scattering cells, are controlled by use of a seed beam injected into the cells. When a laser beam is focused into a phase conjugation cell, a reflected phase conjugated beam is produced. The seed beam is injected at the same frequency and in the same direction as the expected phase conjugated beam, and is adjusted to control the phase and other characteristics of the phase conjugated beam. In multiple cell arrays, seed beams are employed to ensure phase coherency of multiple beams. For lower energy applications, use of the seed beam allows a phase conjugation cell to be operated with incident beams of lower energy than would be needed without the seed beam.

Motion detection, novelty filtering, and target tracking using an interferometric technique with GaAs phase conjugate mirror

Abstract: A method and apparatus for detecting and tracking moving objects in a noise environment cluttered with fast- and slow-moving objects and other time-varying background. A pair of phase conjugate light beams carrying the same spatial information commonly cancel each other out through an image subtraction process in a phase conjugate interferometer, wherein gratings are formed in a fast photorefractive phase conjugate mirror material. In the steady state, there is no output. When the optical path of one of the two phase conjugate beams is suddenly changed, the return beam loses its phase conjugate nature and the interferometer is out of balance, resulting in an observable output. The observable output lasts until the phase conjugate nature of the beam has recovered. The observable time of the output signal is roughly equal to the formation time of the grating. If the optical path changing time is slower than the formation time, the change of optical path becomes unobservable, because the index grating can follow the change. Thus, objects traveling at speeds which result in a path changing time which is slower than the formation time are not observable and do not clutter the output image view.