Multibeam coupling in photorefractive SBN:Ce

Theoretical and experimental results are presented for simultaneous multibeam coupling in photorefractive SBN:Ce. Within a single crystal, multiple signals are amplified through a coupling process that employs a single pump. The coupling gain of each signal results from coupling both between the pump and the signal and between different signals. The amount of gain that each signal receives is dependent on the intensity of the incident signal; thus a competition for the gain exists among the various signals.

Grating-encoded multichannel photorefractive incoherent-to-coherent optical conversion

A dynamic multichannel incoherent-to-coherent optical converter based on the photorefractive effect of SBN:Ce is described. A number of grating-encoded input images, illuminated by incoherent light, are projected onto the crystal to yield photoinduced phase gratings. Coherent positive replicas of these images are simultaneously reconstructed by a coherent read beam. A simple theoretical description of this converter and corresponding experimental results are presented.

曙红薄膜的非线性近共振饱和吸收

近共振增强光学非线性材料及其在光学信号处理中的应用近十年来倍受重视。如相位共轭反射镜和光双稳态器件在光学联想存贮及光学数字处理器中的应用研究。人们在积极开发半导体材料(GaAs,InSb等)和光折变材料(BSO,BaCO_3,SBN等)的同时,开始对有机薄膜材料感兴趣,因为薄膜结构可避免激光光束在体材料中聚焦深度的不均匀性,另外通过压缩膜厚还可降低严格的布拉格条件。本文对由曙红(Eosin)制作的有机薄膜进行了考察。