Proton-induced changes on the optical parameters of a-(Ge20Se80)0.96Ag0.04 thin films

Abstract

Nonoxide, chalcogenide glasses are of interest for application in infrared technology, including the fabrication of optical elements such as mirrors and filters. The low characteristic vibrational frequencies of chalcogenide bonds allow them to transmit far out into the infrared [1]. These glasses show a variety of photostimulated phenomena when exposed to light or other radiations [2, 3]. When these glasses are irradiated with high energy particles or light, bond breaking and bond rearrangement can take place, which results in the change in local structure of the glassy materials. These include subtle effects such as shifts in the absorption edge (photobleaching and photodarkening), and more substantial atomic and molecular reconfiguration such as photoinduced refractive index changes and photodoping effects [4]. In general, these phenomena are associated with the changes in the optical constants [5] and absorption edge shift [6], allowing the use of these materials in the fabrication of a large number of optical devices. This clearly underlines the importance of these glassy materials by accurate determination of their optical constants, refractive index, and extinction coefficient, as well as the corresponding optical band gap.