Iodine-doped Ge-As-Se glasses with high purity and low dispersion.

It is well known that, the incorporation of halide will improve the optical properties of chalcogenide glasses with a broad transparent range. Here, we investigated the optical properties and structure of Ge-As-Se-I glasses in order to disclose the role of halogen iodine in the formation of chalcogenide glassy network. It was found that, refractive index, zero dispersion wavelength and glass transition temperature Tg decrease with increasing iodine contents, while the cut-off edge (λ vis) in the shorter wavelength blue-shifts apparently, and the whole transmission range is expanded widely. The glasses show good chemical stability against moisture. The zero dispersion wavelength of the glasses can be decreased to 4.32 μm by iodine-doping. The evolution of Raman spectra of the glasses indicates that, there is no obvious peak of iodine in Ge-As-Se-I glasses and the dominated glassy network are still the (Ge Se) heteropolar bonds. Unlabelled Image • These novel glass samples possess wide IR transparent window of 0.75-18 μm. • The ZWD of the glass can be decreased to 4.32μm while the refractive index is as low as 2.162 @1.7μm. • The strong absorption peaks of Ge O bond(12.5μm) and H 2 O(6.31μm) are all eliminated after effective purification. [ABSTRACT FROM AUTHOR]