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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TL;DR: A novel real-time technique to measure phonon dynamics using the Raman-induced phase-conjugation method in combination with streak-camera technology to determine vibrational and optical phonon dephasing kinetics of CS, calcite, and LiNbO.
Abstract: A novel real-time technique to measure phonon dynamics using the Raman-induced phase-conjugation method in combination with streak-camera technology is described. The technique is used to determine vibrational and optical phonon dephasing kinetics of CS2, calcite, and LiNbO3 with a temporal resolution of 3 psec.
14 citations
TL;DR: Degenerate four-wave-mixing phase conjugation is analyzed in the case of two-photon transitions between levels having unequal dipole moments and it is shown that lower intensities are sufficient to reach higher reflectivities.
Abstract: Degenerate four-wave-mixing phase conjugation is analyzed in the case of two-photon transitions between levels having unequal dipole moments. The theoretical treatment is based upon a nonperturbative solution of the density matrix and does not require the rotating-wave approximation. We give an analytical expression for the polarization component oscillating at the field frequency for a medium excited by stationary waves. In the weak-probe-beam limit, the contributions in the direction of the probe and conjugated beams are evaluated. For instance, by using this two-photon process, instead of the usual single-photon one which is independent of the permanent dipole moments even in the strong-field limit, it is shown that lower intensities are sufficient to reach higher reflectivities. The influences of the permanent dipole moments, relaxation rates, and field frequency are also discussed.
14 citations
TL;DR: In this article, the results of theoretical and experimental studies of application of parametric wave phase conjugation (WPC) for nonlinear detection of isoechogenic phantoms and for ultrasonic velocimetry of flows are reported.
Abstract: The results of theoretical and experimental studies of application of parametric wave phase conjugation (WPC) for nonlinear detection of isoechogenic phantoms and for ultrasonic velocimetry of flows are reported. Experimental WPC harmonic imaging of isoechogenic phantoms in water was demonstrated on an example of cells filled with a mixture of water and methyl alcohol. Variation of methanol concentration allows obtaining some mixtures with varied nonlinear parameters while their linear acoustic impedance remains close to the water's one. Analysis of harmonics of phase conjugate waves (PCW) in automatically con-focal WPC-system provides reliable detection of the phantoms. According to the theoretical predictions the contrasts of images are comparable with, or even stronger, than the ratio of nonlinear parameters of a phantom and its surrounding medium. 3D-simulation of propagation of PCW in heterogeneously nonlinear and moving media is developed. Break of time reversal invariance of WPC in moving media is proposed as a principle of detection and velocimetry of flows. The results of experimental linear and harmonic imaging of flows in water are presented in comparison with theoretical description.
14 citations
TL;DR: In this paper, a ring self-pumped phase conjugate mirror was used to generate Laguerre Gaussian beam in the pico-second regime for the first time.
Abstract: We have demonstrated highly efficient Laguerre Gaussian beam generation by using a ring self-pumped phase conjugate mirror in the pico-second regime for the first time. The phase conjugate reflectivity was typically ~55%. We have also investigated the conservation of optical angular momentum.
14 citations
TL;DR: In this paper, a self-pumped phase conjugation in a photorefractive liquid crystal light valve with a tilted feedback mirror is reported, which can in general be applied to thin nonlinear layers, opening the way to distortion correction applications of thin media.
Abstract: We report self-pumped phase conjugation in a photorefractive liquid crystal light valve with a tilted feedback mirror. This is a new scheme for the self-generation of a phase-conjugate replica and can in general be applied to thin nonlinear layers, opening the way to distortion-correction applications of thin media.
14 citations