Third-order optical nonlinearity in polycondensed thiophene-based polymers and polysilane polymers

Abstract

The relaxation kinetics and size of the third-order nonlinear susceptibility χ(3) of a homologous series of polycondensed thiophene-based polymers and polysilane polymers were determined by ultrafast nonlinear laser techniques. The wavelength dependence over 530–1060 nm of χ(3) was measured for polycondensed thiophene-based polymers. The resonant χ(3) was determined to be of the order of 10−9 esu. For polysilane polymers, the measured nonresonant χ(3) value was ~10−12 esu. The response time of χ(3) for both polymers was determined to be less than the resolution of optical pulse durations, <3 psec for polysilane and <12 psec for polycondensed thiophene-based polymers.