Investigation And Application On Photorefractive Mutual-Pumped Phase Conjugation

Photorefractive effect is an in-linear optical phenomenon on electro-optic Materials refractive index change with space distributive incident beam intensity. In this thesis, we investigate the properties of the phase-conjugate wave produced by the mutual-pumped and four wave mixing in KNSBN crystal according to need for application in practice.Based on fanning effect experiment in KNSBN crystal, the influence of incident position is studied. Relative a maximum are found with incident position increase for the same input angle,intensity and incident spot diameter, which is in the symmetrical. Since each phase of pump pumping conjugate reflectivity has a maximum, at this time the two beams of light corresponding incident position relative to the surface -c about 3.1 millimetre.The action of incident position effect mechanism is analyzed theoretically.Following the Mutual-pumped phase conjugation properties of KNSBN, experiment studies on the effect of the input angle, and the result shows there exist relations between input angle of Mutual-pumped phase-dependent and have a best input angle for the maximum phase conjugation reflectivity in the symmetrical. Symmetrical each incident pumping phase-conjugate reflectivity has a maximum, at this time the corresponding two light beams Angle of about 45°, and in asymmetric incident phase-conjugate reflectivity and decreases with the Angle, when the two light beams Angle between more than 60°, phase-conjugation reflectivity value almost 0. But Mutual-pumped phase conjugation reflectivity is decrease with input angle increase. A beam of light spot size to another a beam of light conjugation phase properties influence, get a bunch of incident light from pumping phase-conjugate reflectance R as another bunch of symmetrical disk incident light is decreased. But when the original the bunch of constant incident light spot gradually become the big, since pumping phase-conjugate reflectance R corresponding value than before a spot of the corresponding value big; Mutual-pumped phase conjugation reflectance R as another bunch of symmetrical disk incident light increases while, at the same time, when the same of this original incident light spot gradually become the big, mutual-pumped phase-conjugate reflectance R corresponding value than shake a flare incident of the corresponding value big, and increasing range gradually slow. The last will tends to be a fixed value; Total phase-conjugation reflectance R as another bunch of symmetry of incident light spot and decreases and the end all will be their respective a stable value. But if that same the bunch of the original incident light spot gradually become the big, total phase-conjugate reflectance R corresponding value than before a spot of the corresponding value big.The influence of the input optical power on phase conjugate properties was investigated. The maximum output conjugation is found in the certain input optical power ratio when the input position and the input angle were made certain. The results show the self-pumped phase conjugation and mutual-pumped phase conjugation was competed and erased each other. The phase conjugation reflectivity increase when the noise grating was erased or the phase conjugation reflectivity reduced when the main grating was erased. The coexistent condition of Self-pumped phase conjugation and mutual-pumped phase conjugation is introduced in the study.A variety of potential applications in mutual-pumped phase conjugation are studied based on experiment and theoretical analysis.