Photoelectric, nonlinear optical and photorefractive properties of polyimide doped with J-aggregates of cyanine dye

摘要

Novel solid-state photorefractive compositions consisting of the aromatic polyimide (T_g is about 230 ℃) and the thiacarbocyanine dyes were prepared. THese systems have the high net gain coefficient, Γ-α, about 360 cm~(-1). THe dyes form the nanocrystalline J-aggregates that are responsible for photoelectric sensibility in the region of action of Ar-Kr laser and are known to have also very high third-order macroscopic polarizability. The Kerr electrooptical effect is mainly responsible for the light induced refractive index change. It is estabhished that the charge photogeneration time constant determines the time of the photorefractive grating formation and depending on the dye used may be about 20 ms. So, it became possible to develop the solid-state high-performance photorefractive layers based on the polymer with high T_g.