Tuning of the emission frequency of waveguide CO2 lasers with radiofrequency excitation of the active medium

The results are reported of an investigation of the characteristics of the radiation emitted by cw waveguide CO₂ lasers utilizing radiofrequency (rf) excitation, without circulation of the gas mixture. The possibility is discussed of increasing the tuning frequency range of such lasers by changing to a waveguide of rectangular cross section. Continuous tuning of the emission frequency of a laser was achieved over a range of 800 MHz using a pump frequency of 125 MHz and an rf generator power of 50 W. In the case of a nonselective resonator, an output power of more than 4 W was obtained and the efficiency was 7.5%.