Abstract

Photosensitive materials find important applications because they can be used to record optical elements such as Bragg gratings, waveguides or phase masks. One example of such a material is photo-thermo-refractive (PTR) glass. PTR glass is a photosensitive silicate glass doped with cerium, silver, and fluorine. After UV-exposure and thermal development the precipitation of a nano-crystalline phase induces a refractive index change in PTR glass. High efficiency volume phase gratings have been successfully recorded inside PTR glass [1]. In this paper we investigate the features of refractive index modulation after excitation of PTR glass by high intensity IR femtosecond pulses and show as an example, how this non linear photosensitivity can be used for the recording of a Fresnel lens.

© 2007 IEEE