Reversible and irreversible index gratings in a NPP-doped low-T_g polymer composite

摘要

A reversible photorefractive grating and an irreversible local photo-induced aggregation grating were observed in a low glass transition temperature polymer composite poly(N-vinylcarbazole): 2,4,7-trinitro-9-flur-oenone: N-ethylcarbazol: N-(4-nitrophenyl)-(l)-prolinol. Two gratings were distinguished by using the two-beam coupling (TBC) experiment and the four-wave mixing experiment. For photorefractive grating, the TBC coefficient was measured to be 140 cm~(-1) at an applied electric field of E_0 = 85V/μm, corresponding to a photorefractive grating of 3.6 * 10~(-3). The photo-induced aggregation grating was measured to be about 7 * 10~(-3).