High-power phosphate-glass laser system: design and performance characteristics

A one-beam prototype of a large twenty-four-beam phosphate-glass laser system has been built and tested. Basic design characteristics include Nd-doped phosphate glass, rod amplifiers up to 90-mm diam, the propagation of a circularly polarized beam, extensive spatial filtering and imaging, and the use of large-aperture Pockels cells. The prototype system has demonstrated focusable power in excess of 750 GW/beam at 50-psec full width at half-maximum (FWHM) pulse duration and has delivered 165 J of focusable energy in a 500-psec (FWHM) pulse. Maximum beam brightness has been measured to be 4 x 10(19) W/cm(2) .sr at a firing rate of 2 shots/hr. Peak-to-background energy contrast of 10(8) has been achieved with this system. A detailed description of the system design and performance is presented.