High-fidelity Phase Conjugation Research Articles

Self-pumped phase conjugation of light beams carrying orbital angular momentum

We investigate the properties of angular momentum carrying vortex beams, reflected by a phase-conjugating mirror. It is shown that a self-pumped photorefractive phase-conjugating mirror is suitable to produce stable, high-fidelity phase conjugation of vortex beams. We prove that the topological charge of the vortex beam is maintained, and thus the angular momentum in the laboratory frame of reference is reversed, as it is expected by the time reversal property of the phase-conjugating mirror. The three dimensional interference pattern in front of the phase-conjugating mirror is studied and applications in optical traps are suggested.

Mechanism of self-pumped phase conjugation in photorefractive crystals

A two-dimensional model for the self-pumped phase conjugation in a photorefractive crystal is presented. In the model, no internal reflections at a corner of the crystal are explicitly considered, aside from some low intensity scattered radiation at the crystal surfaces. The numerical simulations of the curved beam path inside the crystal show agreement with experimental observations. The numerical results of high-reflectivity and high-fidelity phase conjugation are consistent with experimental results.

High-fidelity phase conjugation and real-time orthoscopic three-dimensional image projection in BaTiO_3

The behavior of high-fidelity phase-conjugation systems that use mutually phase-conjugate pumps in photorefractive BaTiO3 is studied. A system performing two phase-conjugation operations on a single signal input is demonstrated. This scheme uses the primary phase-conjugate field generated by self-pumping in an external dynamic feedback configuration to produce a second phase-conjugate field. This technique produces high-fidelity, temporarily stabilized phase conjugation and is used here to demonstrate real-time orthoscopic, three-dimensional image projection.

High-fidelity image amplification and phase conjugation in photorefractive Bi_12SiO_20 crystals

Wide-angle, large space-bandwidth-product coherent image amplification with a flat spatial frequency response is demonstrated in photorefractive Bi(12)SiO(20) crystals under nonstationary grating recording conditions. By utilizing large-divergence, mutually phase-conjugate pump beams provided by a self-pumped BaTiO(3) crystal, high-fidelity phase conjugation with high reflectivity in Bi(12)SiO(20) is demonstrated.

Phasar Nonlinear Optical Experimentation: Phased Far-Field Return From Multiple Telescopes By Optical Wavefront Reversal Of A Reference Signal

A multiple telescope array, Phasar, is used to collect light for a phase-conjugate mirror of barium titanate, forming a hybrid receiving/ transmitting system. The observed fidelity of the system output is independent of the type and amount of aberration introduced into the optical path. In all test cases, the measured far-field peak intensity indicates that the fidelity of the return from the three telescopes approaches the fidelity required to yield the ideal in-phase superposition of waves in the far field. The system demonstrates high fidelity phase conjugation for a telescope piston mismatch of up to ±5 Am, for tilt error up to ±700 grad, and for higher order aberrations. A scheme implemented to compensate for depolarizing and polarization-altering effects boosts the amplitude of the point spread function considerably. Near-field diagnostics confirm the fidelity of the phase-conjugate output.

Non-frequency-shifted, high-fidelity phase conjugation with aberrated pump waves by Brillouin-enhanced four-wave mixing

The results of an experimental investigation of a new geometry for producing phase conjugation by Brillouin-enhanced four-wave mixing are presented. In this geometry, the four-wave mixing medium is carbon disulfide, and the backward-going pump wave is created from the transmitted forward-going pump wave by stimulated Brillouin scattering (SBS) in glycerol. The two pump waves are hence phase conjugates of each other, and the quality of the phase-conjugation process is not degraded even by the use of an aberrated pump wave. The probe wave is created by SBS in carbon disulfide, which has a Brillouin frequency half that of glycerol, and the conjugate wave is therefore generated at the same frequency as the probe. Since the pump and signal waves differ in frequency by the Brillouin frequency of the carbon disulfide four-wave mixing medium, high reflectivities (approximately 2000%) are obtained as a result of Brillouin resonance enhancement.