Spectral Combining and Coherent Coupling of Lasers by Volume Bragg Gratings

The use of volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass for laser beam control is described. These new optical elements provide extremely narrow spectral and angular selectivity and have a high level of resistance to high-power pulsed and continuous-wave laser radiation. These features of PTR volume gratings are used for transverse and longitudinal mode selection, passive coherent coupling, and spectral beam combining (SBC) of semiconductor, solid state, and fiber lasers.