Topic
Phase conjugation
About: Phase conjugation is a research topic. Over the lifetime, 3694 publications have been published within this topic receiving 49099 citations.
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Patent•
29 Dec 1978TL;DR: In this article, a phase conjugate circuit (PCC) is used to generate the exact conjugates of an incident signal φ* 1 in accordance with the relation R (2φ 0 -φ 1 ) where R is equal to the reciprocal of 1-2/n, and n≧4, using a phase locked loop.
Abstract: An active retrodirective antenna array having central phasing from a reference antenna element through a "tree" structured network of transmission lines utilizes a plurality of phase conjugate circuits (PCCs) at each node and a phase reference regeneration circuit (PRR) at each node except the initial node. Each node virtually coincides with an element of the array. A PCC generates the exact conjugate phase φ* 1 of an incident signal φ 1 in accordance with the relation R (2φ 0 -φ 1 ) where R is equal to the reciprocal of 1-2/n, and n≧4, using a phase locked loop which combines the phases φ 1 and φ* 1 in an up-converter, divides the sum by 2 and mixes the result with the phase φ 0 in a down-converter for phase detection by the phase φ* 1 from the loop oscillator divided by n. The PRR extracts the phase φ 0 from the conjugate phase φ* 1 by mixing φ* 1 divided by 2 and divided by n in a down-converter and then mixing the phase φ 1 divided by 4 with the result of the down-converter in two cascaded up-converters. Both the PCC and the PRR are not only exact but also free from mixer degeneracy.
19 citations
Journal Article•
19 citations
TL;DR: A method for achromatic volume holography is described using a combination of material and grating dispersion with barium titanate as the dispersive material and a bandwidth of 250 nm is realized.
Abstract: A method for achromatic volume holography is described using a combination of material and grating dispersion. With barium titanate as the dispersive material, a bandwidth of 250 nm is realized. The device may be used for broadband phase conjugation and image reconstruction.
19 citations
TL;DR: In this article, a flash-lamp-pumped, Q-switched Nd:YAG oscillator-amplifier system with an average output power of 215 W and a beam-parameter product of less than 1 mm mrad is developed.
Abstract: A flash-lamp-pumped, Q-switched Nd:YAG oscillator-amplifier system with an average output power of 215 W and a beam–parameter product of less than 1 mm mrad is developed. The system operates with a 100-Hz repetition rate and emits a burst of 20 Q-switched pulses during each flash-lamp pulse with pulse durations of 100 ns. The high beam quality of the amplified beam is realized by a double-pass configuration of the amplifiers with a phase conjugating stimulated-Brillouin-scattering cell. Additionally, the thermally induced birefringence of the amplifiers is compensated by a 90° rotator and an optical image-relay system between two identical amplifier rods.
19 citations
TL;DR: A new geometry is developed for Brillouin-enhanced four-wave mixing that performs vector phase conjugation to correct for both wave-front and polarization distortions and shows a reduction in the depolarization losses.
Abstract: It is often desirable to remove both wave front and polarization aberrations from an optical beam. Scalar phase conjugation, such as ordinary stimulated Brillouin scattering, can correct only for wave-front aberrations. We have developed a new geometry for Brillouin-enhanced four-wave mixing that performs vector phase conjugation to correct for both wave-front and polarization distortions. Results show a reduction in the depolarization losses from 50% to less than 2% of the total output energy. Coherent, variable, multiple-beam combination is achieved without need of nonreciprocal devices such as Faraday rotators.
19 citations