Composition dependence of thermally induced second-harmonic generation in chalcohalide glasses

By investigating the second-harmonic generation (SHG) of the series (100 – 2x)GeS2 xGa2S3 xPbI2 (x = 5, 10, 15, and 20) chalcohalide glass samples after thermal poling, it was found that there was an optimal poling temperature for each composition and there was also a relation between optimal poling temperature and glass transition temperature. With increasing x, the obtained second-order susceptibility v(2) shows an increase first and then decrease, and the maximum was seen at x = 15. A dipole reorientation model and structural relaxation causing by Ga2S3 and PbI2 were proposed to explain the dependence of poling temperature on SH intensity for each composition and the presence of the maximum v(2) in this chalcohalide glass series