Anisotropy in Third-Order Nonlinear Optical Susceptibility of the Stretch-Oriented Chrysophenine-Doped Poly(vinyl alcohol) Films

Stretch-oriented chrysophenine-doped poly(vinyl alcohol) (PVA) films were prepared at temperatures above the glass transition temperature of PVA. The optical absorption spectra of the stretch-oriented films exhibited a very high anisotropy (anisotropy ratio = 13). The third-order nonlinear optical properties of chrysophenine in stretch-oriented PVA films were measured by the resonant femtosecond degenerate four-wave mixing (DFWM) technique. The anisotropy ratio of the DFWM signal intensity was greater than 1000. The value of third-order nonlinear optical susceptibility of a uniaxially stretch-oriented chrysophenine-doped PVA film was 6.9×10-13 esu.