High-power two-dimensional waveguide CO2 laser arrays

A two-dimensional, 39 element array of waveguide carbon dioxide lasers has produced a total CW laser power output of 750 W, using RF excitation of a compact, close packed assembly. Thermal effects associated with close-packing in the array are evaluated in terms of discharge wall temperature rise and cavity mirror distortion. The array elements are shown to have a 30% power derating relative to a single isolated laser channel, caused mainly by internal temperature rise. Mirror distortion and waveguide constructional errors do not degrade the beam quality of the array emission, which matches the theoretical value. However mirror distortion is shown to be responsible for a large spread in laser frequency between channels in the array. Based on the results, prospects are good for the construction of larger, multikilowatt incoherent arrays.