Variable linewidth high-power TEA CO_2 laser

A variable linewidth high-power TEA CO2 laser, utilizing a multiple-prism beam expander in conjunction with a Littrow-mounted grating, is described. Linewidths of approximately 250-MHz (FWHM) at a total output energy exceeding 250 mJ have been obtained at the P20 (00 degrees 1-10 degrees 0), lambda = 10.59-microm line. Laser linewidths can be varied continuously in the 250-650-MHz range for a corresponding change in output energy from 250 to 400 mJ. The present frequency selectivity method, which employs ZnSe prisms, can be applied directly to considerably higher-power CO2 lasers.