Large optical Kerr effect in bulk GeSe2–In2Se3–CsI chalcohalide glasses

Third-order nonlinear optical properties of GeSe2–In2Se3–CsI chalcogenide bulk glasses are studied by Standard pico-second (ps) time-resolved optical Kerr effect (OKE) technique. The obtained χ(3) and n2 at 1064 nm of the glass 72.25GeSe2–23.75In2Se3–5CsI are as large as 10.07 × 10−12 esu and 6.5 × 10−18 m2/W, respectively, more than twice that of As2S3 glass. The relationship between glass compositions and the third-order nonlinear optical responses was analyzed by Raman spectra in terms of structural evolution. It is suggested that the tetrahedral units ([GeSe4] and [InSe4]) play an important role in the ultrafast third-order nonlinear optical responses of these chalcohalide glasses.