Third- and second-order optical nonlinearity of Ge–Ga–S–PbI2 chalcohalide glasses

Two series of metal iodide doped chalcohalide glasses (100−2x)GeS2·xGa2S3·xPbI2 (0⩽x⩽20) and (100−x)(0.8GeS2·0.2Ga2S3)·xPbI2 (0⩽x⩽15) were prepared and characterized. The microstructure of these glasses has been studied by Raman scattering spectra. Utilizing femtosecond time-resolved optical Kerr effect (OKE) technique at the wavelength of 820 nm, a largest third-order nonlinearity χ(3) of 2.07×10−13 esu was obtained for the 90GeS2·5Ga2S3·5PbI2 glass, and it decreases with the addition of PbI2 in both two series. After thermally poled, second-harmonic generation (SHG) has been observed in these glasses according to Maker fringe method and a large second-order nonlinearity χ(2) as well as 4 pm/V was obtained for the 70GeS2·15Ga2S3·15PbI2 glass. The variations of χ(2) and χ(3) on glass composition are ascribed to the evolution of micro-structural units in glass. These novel chalcohalide glasses would be expected to be the promising candidate materials for nonlinear optical devices.