John Kiran, A.Udayakumar, D.Chandrasekharan, K.Ahdikari, A.V.Shashikala, H.D.Philip, R.2026-02-052007Optics Communications, 2007, 271, 1, pp. 236-240304018https://doi.org/10.1016/j.optcom.2006.10.003https://idr.nitk.ac.in/handle/123456789/27821We 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 ?(3) determined from both experiments. Z-scan results indicate a negative nonlinear refractive index, n<inf>2</inf>, 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. © 2006 Elsevier B.V. All rights reserved.CopolymersFour wave mixingLight absorptionNeodymium lasersRefractive indexSulfur compoundsOptical limitingPolythiophenesZ-scanNonlinear optics