Editorial for the special issue QSIP18

Chalco-halide glasses possess a low weak absorption tail in the atmospheric IR windows. They have improved optical properties, particularly broadening the mid-infrared cutoff. In this work, we report the synthesis of iodine doped Ge25Sb10Se65-xIx (x = 0, 4, 8, 12, 16) system. The optical behaviour has been analysed using a single reflection spectrum. The reflection spectrum has been obtained using an ultraviolet-visible-near-infrared spectrophotometer for wavelength 400 nm–2500 nm. The static refractive index has shown an increase from 2.76 (x = 0) to 3.33 (x = 16). The dispersive behaviour is found to be normal for all samples. The values of the Urbach energy show an increase in structural disorder. A decrease in the optical band gap has been observed with the addition of iodine amount. The third-order non-linear optical susceptibility obtained from semi-empirical method increases with the iodine content.