Experimental chemical laser mode control

An experimental study was performed on integer and integer plus one-half valued equivalent Fresnel number positive branch confocal unstable resonators in a DF-CO2 flash-photolysis chemical laser. Near diffraction limited beam quality was obtained for a range of geometric output couplings from 30% to 77%. No dependence of beam quality on the resonator Fresnel number was found. This was true for uniform medium conditions as well as perturbed conditions where significant phase perturbation were introduced into the optical resonator. Extensive medium diagnostics were performed on the DF-CO2 laser and the results presented.