Nonlinear optical studies of a newly synthesized copolymer containing oxadiazole and substituted thiophenes

We investigated the third-order nonlinear optical properties of a newly synthesized soluble copolymer containing oxadiazole and thiophene units using Z-scan and Degenerate Four Wave Mixing (DFWM) techniques. The measurements were performed at 532 nm with 7 ns pulses from a Nd:YAG laser. We found a good agreement between the values of χ(3) determined from both experiments. Z-scan results indicate a negative nonlinear refractive index, n2, whose magnitude is of the order of 10−10 esu. The copolymer exhibits strong nonlinear absorption and good optical limiting properties at 532 nm, and hence may be a potential material for optical limiting applications.