title: Origin of photo-induced transmitting oscillations in chalcogenide glasses.
abstract: Light-induced oscillatory behaviors of transmission in chalcogenide glasses are investigated using a continuous wave tunable Ti-sapphire laser. It is shown that phase change, thermal fluctuation, nonlinear index change and periodic self focusing are not at the origin of light-induced oscillatory transmittance in chalcogenide glasses. Instead, results indicate that the interference of transmitting and reflecting light is at the origin of the oscillatory behaviors of transmitted light. Just like the principle of Fabry-Pérot interferometer, these interferences result in a periodic change in transmission as the related interferential beams get in and out of phase. However, this transmitting oscillatory behavior can be registered by the detector only when the change of optical path length difference initiated by photo-induced effects is slower enough compared with the corresponding response time of the detector. Several photo-structural effects contribute to that phenomenon including photo-expansion, photo-darkening, and permanent self focusing. It appears that fluctuations of the light source intensity induce a wide distribution of the oscillatory periods.
authors.affiliation: Key Laboratory of Silicate Materials Science and Engineering (Wuhan University of Technology), Ministry of Education, Wuhan, Hubei 430070, PR China. taohaizheng@hotmail.com
authors.forename: HaiZheng
authors.initials: H
authors.lastname: Tao
authors.forename: ZhiYong
authors.initials: Z
authors.lastname: Yang
authors.forename: Pierre
authors.initials: P
authors.lastname: Lucas
mesh_terms: D018011:Chalcogens / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D005898:Glass / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008956:Models, Chemical; D009991:Oscillometry / Q000379:methods*; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation
chemical_list: D018011:Chalcogens