OPTIGRATE CORPORATION — Department of Defense SBIR Phase I: N161-063

Description

High power ultrashort pulse lasers (USPLs) are important for material modifications on the micron scale with minimal or precisely controllable heat effects, cataract surgery, atmospheric diagnostics, especially in remote sensing, etc. In particular the LIDAR method has become a powerful technique to monitor atmospheric parameters and has helped to understand a variety of atmospheric phenomena. <br>We propose to use transverse mode selection in large aperture master oscillator followed by coherent beam combining approach in order to increase the energy of ultra-short pulse lasers without chirped pulse amplification. This approach is based on the advances in volume Bragg gratings technology development. We recently succeeded in recording of multiple transmitting Bragg gratings inside a single plate of PTR glass. Recording of gratings with orthogonal planes of diffraction allowed transverse mode selection for two axes simultaneously and therefore allows single transverse mode operation of multimode solid state lasers. It gives us additional opportunity to use large aperture glass/crystal gain media and high power pump diodes keeping the high beam quality. The use of multiplexed transmitting gratings with parallel planes of diffraction will be used for coherent combining of several large aperture oscillators.