Abstract

Because of the inherent loss of optical systems, image amplification can be required in massively parallel optical architectures. This amplification can be obtained through the two wave mixing interaction in photorefractive crystals [1]. However, for sensitive material such as sillenite crystals one has to compensate for the relatively low electrooptic coefficient by an appropriate enhancement recording technique. One method to enlarge the photorefractive gain is to apply an alternating field to the crystal [2]. Consequently all the properties of the amplified beam (phase, polarization and intensity) will oscillate at the electric field frequency. Therefore, special care should be taken when inserting such an amplifier in an optical system so that the time dependent characteristics of the amplified beam are not disturbing the operation of any next non linear device. For this reason, using the coupled wave formalism [3], we study in the following all the features of the amplified beam under an alternating electric field.

© 1989 Optical Society of America