Femtosecond photoinduced dichroism in polydiacetylene 4bcmu film

Abstract

Femtosecond pulses were used to study the photoexcitation dynamics and transient photoinduced dichroism in polydiacetylene 4BCMU film. Ultrafast photoinduced dichroism and optical Kerr gate response were observed. These measurements allowed estimation of the diffusion constant (D∼0.1 cm2/s), nonlinear index of refraction (n2∼10−8 esu), and third-order susceptibility (Δχ(3)∼6 × 10−10 esu), in the film.