The Nature of the Defects in Phosphate-Based Glasses Induced by Gamma Radiation

Final optics assembly is one of the most important parts in high energy and large-scale laser systems like US National Ignition Facility and SG III in China. Those final optics assembly are facing some severe tests, like the laser-induced damage caused by 3ω (351 nm) laser irradiation. Meanwhile, the irradiation of gamma ray and X-rays, will also cause the changes of optical properties in the investigated multi-component phos- phate glasses that have potential use in novel color separation optics in high power laser facilities. These changes of optical properties are associated with the defects induced by gamma radiation. In details, some defects contribute to the absorption in the UV region, which will deteriorate their UV performance. However, some of the induced defects can be eliminated by thermal treatment due to the release and capture of the electrons in conduction band. Besides, the doped Fe, Co, B, Ce and Sb will also affect the defect-state in phosphate-based glasses. In details, gamma radiation resistances of the phosphate glass can be greatly improved by CeO 2 and Sb 2 O 3 co-doping, and the introduction of B 2 O 3 reduces the connectivity of phosphate chains and thus increases the concentration of PO 3 -EC and PO 4 -EC defects.