Electrooptical applications photorefraction

LiNbOj is a widely used ferroelectric crystal with various applications in the nonlinear optics and integrated optics (10). Another attractive material for 10 devices is LiTaOs. Its electrooptic (EO) and nonlinear (NL) coefficients are comparable to those of LiNbOj, and its photorefractive damage threshold is more than an order of magnitude higher than that of LiNbOj in the visible range. 

For several decades, the fields of photoconducting (75) and purely electrooptic polymers (74) have been very active but had almost no direct overlap. With the development of photorefractive polymers in the early nineties, the knowledge of these two research areas could be combined and has led to a rapid improvement of the performance of existing photorefractive polymers. The photorefractive polymer composite DMNPAA PVK ECZ TNF (DMNPAA 2,5 -dimethyl-4-(p-nitrophenyl-azo)anisole PVK poly(N-vinylcarbazole) ECZ N-ethylcarbazole TNF 2,4,7-trinitrofluorenone) we developed recently (P) has reached a level of performance that competes with that of the best inorganic photorefractive crystals (77,72). With the recent progress achieved in the development of new chromophores for electro-optic applications (75), the efficiency of these new materials is expected to be significantly further improved. 

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