Large area discharge RF excited CO₂ laser

A planar, RF-excited CO₂ laser with an electrode spacing of 7.5 mm and a total discharge area of 320 cm² is described. It emits a multimode output of 330 W for a 2-kW input, corresponding to a specific power output of 10 kW m^-2. The laser has been used as part of a program to establish the scalability of the large-area concept and to provide detailed information on the gas temperature and carbon dioxide dissociation rates in this novel discharge format. Dissociation rates have been quantified by transfer of gas leaving the discharge in the slow-flow mode to a gas chromatograph system. The degree of dissociation observed at the output of the discharge for a gas mixture of 7:18:75 CO₂:N₂:He closely correlates with the flow dependence of the output power of He-rich mixtures. The data are useful for the assessment of gas consumption and the tradeoff power that must be made as the flow rate and He content are reduced toward static gas conditions.