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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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01 Feb 1995
TL;DR: In this paper, the Scalar Helmholtz Equation for Nonuniform Media (SHE) is used to measure the information capacity of Holographic Memory with 3D Holograms.
Abstract: Speckles in Holography. Introduction to the Problem: Interference and Spatial Structure of a Light Beam. Properties of Speckle Fields. Types of Holograms of Speckle Fields. Main Parameters of Holograms. Diffraction of Light by Sinusoidal Grating. Noise Characteristics of HologramS. The Problem of Information Capacity of Holographic Memory: Light Beam Degrees of Freedom. Capacity Limit for Two-Dimensional Recording of Information. Holographic Memory with Three-Dimensional Recording. Estimates for Limiting the Information Retrieval Rate. First Born Approximation Theory of Hologram Readout: Derivation of the Scalar Helmholtz Equation for Nonuniform Media. Amplitude of Reconstructed Object Waves. Strength of the Hologram. Amplitude of Conjugate Waves. The Condition of Volume Regime. Spectral-Angular Selectivity. Photoresponse Saturation and Grating Strength. Holograms of Speckle Waves: Diffraction Efficiency of Holograms of Speckle Waves. Diffraction Efficiency and Noise at Photoresponse Saturation for Thin-Layer and Thick-Layer Holograms. Selectivity of Holograms of Speckle Fields. Spectral-Angular Distortions. Holograms of Speckle Reference Waves. Readouts of Holograms at High Grating Strength: Thin- and Thick-Layer Holograms of Enhanced Efficiency. Specklon. Calculation of Extinction Coefficients for Specklon. Reconstruction of Speckle Fields by Volume Holograms and Effect of Selectivity Curve Shift. Intramodulation Noise of 3-D Holograms. Referenceless Holograms. Superimposing Exposures at Partial Correlation between Object Fields. Hymn of Praise for 3-D Holograms. Self-Action of Speckle Beams in Nonlinear Media: Brief Review of Nonlinearities for Dynamic Holography. Self Phase Modulation of Speckle Beam. Suppression of Self-Focusing by Speckles. Self-Binding of a Speckle Beam. Two Wave Mixing: Plane Wave Model of Two Wave Mixing. Self-Phase Conjugation Via Backscattering. Transient Energy Transfer of Speckle Beams in Accumulating Media. Stabilization of Dynamic Recordings of Volume Holograms. Checking (Verifying) the Specklon Theory in Two-Wave Mixing Experiment. Two-Wave Coupling Via Diffusion Nonlinearity. Speckle Effects in Multiwave Mixing: Instability of Phase Conjugated Speckle Waves in Kerr-Like Media. Double Phase Conjugation. Self-Biting Scheme of Phase Conjugation. Build-up of Self-Conjugating Oscillation in Nonlinear Cavities.
44 citations
TL;DR: The results show that the real part of n2 in ruby is an order of magnitude larger than the imaginary part, which clarifies the controversy about the dispersive or absorptive origin of the phase conjugation in ruby- and cromium-doped crystals.
Abstract: A differential interferometric method for direct measurements of the real part of the nonlinear index of refraction n2 has been developed. With this method we were able to measure n2 as low as 10−10 cm2/W. This method was used to measure n2 in both ruby and GdAlO3:Cr+3 for the first time. Our results show that the real part of n2 in ruby is an order of magnitude larger than the imaginary part. This result clarifies the controversy about the dispersive or absorptive origin of the phase conjugation in ruby- and cromium-doped crystals.
44 citations
TL;DR: In this paper, the authors show that conventional phase conjugation is not able to achieve the dark nulls needed for high-contrast imaging and present an alternative optimized solution for the shape of the deformable mirror based on the Fourier decomposition of the effective phase and amplitude aberrations.
Abstract: Conventional adaptive-optics systems correct the wavefront by adjusting a deformable mirror (DM) based on measurements of the phase aberration taken in a pupil plane. The ability of this technique, known as phase conjugation, to correct aberrations is normally limited by the maximum spatial frequency of the DM. In this paper we show that conventional phase conjugation is not able to achieve the dark nulls needed for high-contrast imaging. Linear combinations of high frequencies in the aberration at the pupil plane "fold" and appear as low-frequency aberrations at the image plane. After describing the frequency-folding phenomenon, we present an alternative optimized solution for the shape of the deformable mirror based on the Fourier decomposition of the effective phase and amplitude aberrations.
44 citations
TL;DR: This optical oscillation locks the relative phase of the two phase-conjugate reflections such that they recombine at the beam splitter to form only a single beam as though they were truly time-reversed waves.
Abstract: A new type of interferometer has been constructed that uses a beam splitter and two self-pumped BaTiO3 crystals as phase-conjugate reflectors in place of the usual interferometer mirrors. Counterpropagating beams of light are spontaneously generated between the two crystals, coupling the pair of phase conjugators. This optical oscillation locks the relative phase of the two phase-conjugate reflections such that they recombine at the beam splitter to form only a single beam as though they were truly time-reversed waves.
44 citations
TL;DR: The theory for phase conjugation in stimulated scattering is described in detail in detail as mentioned in this paper, and the basic experimental results on the conjugations are also discussed in detail, as well as the intervals of values of various parameters in which the conjogate configuration (the specklon) exists.
Abstract: Various aspects of optical phase conjugation are discussed: the properties of the conjugate wave, its potential applications, the basic conjugation methods, and a brief history of the question. The theory for phase conjugation in stimulated scattering is set forth in detail. The basic experimental results on this conjugation method are also discussed in detail. Phase conjugation occurs because that configuration of the back-scattered field which has the conjugate wavefront is amplified to the greatest extent (at a doubled gain) in the intense speckle-inhomogeneous conjugate wave in a medium in which stimulated scattering occurs. Because of the large overall amplification in stimulated scattering, all the other, uncorrelated, configurations of the spontaneously scattered nucleating waves are amplified by a factor of 107 less and are discriminated against. The intervals of values of the various parameters in which the conjugate configuration (the specklon) exists are discussed theoretically, as is the effect of nonlinear selection and saturation on phase conjugation in stimulated scattering. There is a review of experimental results on the first observation of the effect, on the measurement of the angular structure of the uncorrelated waves and of the extent to which they are discriminated against, on the phase fluctuations of the conjugate wave, on the conjugation of subthreshold and depolarized radiation, and on phase conjugation in stimulated scattering in focused beams and for other scattered-wave amplification mechanisms.
44 citations