A photosensitive glass demonstrating refractive index decrement after exposure to UV radiation followed by thermal development is used for phase volume hologram recording. This photo-thermo-refractive (PTR) glass is a sodium zinc aluminium silicate glass doped with cerium, silver and fluorine. Spatial modulation of refractive index resulted from precipitation of nanocrystalline phase of sodium fluoride. Volume bragg gratings recorded in this glass, show extremely narrow spectral and angular selectivity and have low losses combined with high tolerance to laser radiation. These gratings possess a unique ability to produce laser beam transformations directly in angular space. This feature paves a way to creation of high power semiconductor lasers with stable narrow emission spectra & diffraction limited divergence.
