Yujin Zheng

INCIDENT BEAM CONDITION DEPENDENCE OF RATIO BETWEEN TWO PHASE-CONJUGATE TRANSMISSIVITIES IN DOUBLE-PHASE-CONJUGATE MIRROR

Abstract It is observed that the ratio between two phase-conjugate transmissivities of two incident light ways depends on incident beam position rather than the ratio of two incident beam intensities in a KNSBN:Cu double-phase-conjugate mirror. A model with two one-dimensional interaction processes in an interaction region is presented and explains the experimental results. On the nature of the double-phase-conjugate mirror, the two phase-conjugate transmissivities are not always equal.

High-Efficiency Bridge Double Phase-Conjugate Mirrors in Cu-Doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 Crystals

In this paper, we report the formation of high-efficiency double phase-conjugate mirrors with the bridge incident geometry in Cu-Doped (K 0.5 Na 0.5 ) 0.2 (Sr 0.61 Ba 0.39 ) 0.9 Nb 2 O 6 (Cu :KNSBN) crystals. These bridge double phase-conjugate mirrors have high efficiency, even under low incident power. For crystals with different absorption coefficients, the optimum incident geometries of the bridge double phase-conjugate mirrors were observed and discussed.

Formation Mechanism of Self-Pumped Phase-Conjugate Mirror Using a Cu-Doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 Crystal

In this work, we study the formation mechanism of the self-pumped phase-conjugate mirror (SPPCM) in a Cu doped (K 0.5 Na 0.5 ) 0.2 (Sr 0.61 Ba 0.39 ) 0.9 Nb 2 O 6 (KNSBN:Cu) crystal using an Ar + laser (λ=514 nm). The gain of selfpumped four-wave mixing is greater than that of self-generated fanning, which leads the self-formation of the SPPCM. The beam-fanning profiles vary with the laser beam incident angle. We observed that multiple fanning loops are formed and change with the change in incident angle in the SPPCM. Experimental results and discussion show that the transmission grating is responsible for the generation of the SPPCM. The phase-conjugate reflectivity increases with the increase in coupling constant

Stable High-Efficiency Double-Phase-Conjugate Mirror in a Cu-Doped Potassium Sodium Strontium Barium Niobate Crystal

We report a stable high-efficiency double-phase-conjugate mirror (DPCM) in a Cu-doped potassium sodium strontium barium niobate (KNSBN:Cu) crystal. The stable high phase-conjugate transmissivity reaches 55% when using a mW-order low-power Ar+ laser at a 514 nm wavelength with two mutually incoherent incident beams. The relative stability of the phase-conjugate transmissivity of as high as 93% was obtained in 150 minutes. The incident-location and angle responses of the phase-conjugate transmissivity were observed. Unstable behaviour of the DPCM was also observed and discussed.

All-Optical Switching Dynamic Interconnection with Multiple Mutually Pumped Phase Conjugators

An all-optical controllable dynamic interconnection and an all-optical switching dynamic interconnection are demonstrated using the arrangements of the multiple mutually pumped phase conjugators in a photorefractive Cu-doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 [Cu:KNSBN] crystal. The ON and OFF states of dynamic interconnection between the two light beams were dominated by a control beam. The dynamic interconnections of the multiple light beams were also optically switched via the incidence of the different control beams.

Enhancement of Time Response of Self-Pumped Phase-Conjugate Mirror in KNSBN:Cu Crystal Using Cylindrical Lenses

In this study we investigate the effect of incident beam diameters and profiles on time response and phase-conjugate reflectivity in a KNSBN:Cu crystal self-pumped phase-conjugate mirror. The time response of a self-pumped phase-conjugate mirror can be effectively enhanced by using two cylindrical lenses to increase incident light density without reduction of coupling strength. In maximum phase-conjugate reflectivity, the time response obtained using two cylindrical lenses is 4 times faster than that using a spherical lens.