Ultrafast third-order optical non-linearity of 0.56GeS2―0.24Ga2S3―0.2KX(X = Cl, Br, I) chalcohalide glasses by femtosecond Optical Kerr Effect

Abstract 0.56GeS 2 –0.24Ga 2 S 3 –0.2KX(X = Cl, Br, I) chalcohalide glasses were prepared and their third-order optical non-linearities χ (3) have been studied systematically using the femtosecond time-resolved Optical Kerr Effect technique at wavelength of 800 nm. In this system, 0.56GeS 2 –0.24Ga 2 S 3 –0.2KCl glass shows the largest χ (3) (1.82 × 10 −13  esu), but 0.56GeS 2 –0.24Ga 2 S 3 –0.2KBr glass has the fastest optical non-linear response time in subpicosecond domain (about 340 fs), which is due to the ultrafast distortion of the electron clouds surrounding the balanced position of Ge, Ga, S, K and Br atoms. The local hyperpolarizability determining non-linear optical response are determined by the partially ionic bonds originating from Ge(Ga)–S bonds and halogen valence bonds. They show great potential applications on the glass-based optoelectronic devices like optical switching.