First steps in the development of next-generation chirped volume Bragg gratings by means of fs laser inscription in fused silica.

The first steps towards the development and characterization of next-generation chirped volume Bragg gratings (CVBGs) by means of fs laser inscription were made. Based on the phase mask inscription technique we realized CVBGs in fused silica with a 3 × 3 mm2 aperture and a length of almost 12 mm with a chirp rate of ∼190 ps/nm around a central wavelength of 1030.5 nm. Strong mechanical stresses induced serious polarization and phase distortions of the radiation. We show a possible approach to solution of this problem. The change in the linear absorption coefficient associated with local modification of fused silica is quite small, enabling utilization of this type of gratings in high average power lasers.