Amplified reflection, transmission, and self-oscillation in real-time holography

A theory of phase conjugation in asymmetric materials that allow a phase shift between the grating and the light-interference pattern is developed. We find that when this phase is nonzero, maximum phase-conjugate reflectivity occurs for unequal pump intensities. The conditions for self-oscillation are studied

Passive (self-pumped) phase conjugate mirror: Theoretical and experimental investigation

We report the results of a theoretical and experimental investigation of a passive (self-pumped) phase conjugate mirror. This device is based on real time holography in materials which allow a spatial phase shift between the refractive index grating and the light interference pattern. An imaging experiment is reported showing the phase conjugating nature of the device. The holographic medium used was a single crystal of barium titanate

Theory and applications of four-wave mixing in photorefractive media

The development of a theory of four-wave mixing in photo-refractive crystals is described. This theory is solved in the undepleted pumps approximation with linear absorption and without using the undepleted pumps approximation for negligible absorption. Both the transmission and reflection gratings are treated individually. The results are used to analyze several photorefractive phase conjugate mirrors, yielding reflectivities and thresholds. The use of photorefractive crystals as optical distortion correction elements and experimental demonstrations of several of the passive phase conjugate mirrors are described

Exact solution of a nonlinear model of four-wave mixing and phase conjugation

An exact solution of a nonlinear model of holographic four-wave mixing is derived. An expression for the reflectivity of a phase-conjugate mirror with depleted pumps is presented. We find that such a phase-conjugate mirror may exhibit bistability

Nonlinear vectorial two-beam coupling and forward four-wave mixing in photorefractive materials

We present an exact solution of a nonlinear vector analysis of two-beam coupling and forward four-wave mixing in photorefractive media

Real-time phase conjugate window for one-way optical field imaging through a distortion

We demonstrate one-way optical field imaging through a distorting medium using a four-wave mixing implementation of real-time holography. Information can be transmitted at an arbitrarily fast rate as long as the mixing medium can respond to changes in the distortion

Coherent oscillation by self‐induced gratings in the photorefractive crystal BaTiO_3

We report here the demonstration of several new optical oscillator configurations including a unidirectional ring oscillator and a self‐pumped phase conjugate mirror. The gain medium is BaTiO_3, pumped by a 632.8‐nm He‐Ne laser at power levels down to 50 μW

Passive phase conjugate mirror based on self-induced oscillation in an optical ring cavity

A passive phase conjugate mirror based on four-wave mixing in an optical ring cavity is described. Unlike previously demonstrated passive phase conjugate mirrors it generates only one of its pumping beams by nonlinear optical interactions, the other being provided by feedback of the probe after transmission through the nonlinear medium. The results of a theory yielding phase conjugate reflectivity and oscillation thresholds are presented together with an experimental demonstration of phase conjugation in barium titanate and strontium barium niobate. The device is self-starting by four-wave mixing, and has an oscillation threshold lower than that of other previously demonstrated passive phase conjugate mirrors with similar ease of alignment. The operation of a device which generates nonconjugate oscillation beams is also reported

Amplifying continuous wave phase conjugate mirror with strontium barium niobate

We report the use of Sr_(1−x) Ba_x Nb_2O_6 as an efficient holographic four‐wave mixing medium. We have used this material in a continuous wave phase conjugate mirror with reflectivity exceeding unity, and in a phase conjugate resonator