Advances in stable CO2laser design and performance

The design and performance of stable, sealed-off, single-frequency CO2lasers developed at Lincoln Laboratory were last discussed at the June 1967 CLEA Meeting and in the June 1968 issue of the IEEE Journal of Quantum Electronics. Since then, there have been many modifications and additions to the design with the aim of improving performance, versatility, and ease of assembly. An entirely new modular, internal mirror cavity frame was designed into which a choice of mirror holders, piezo-electric tuners, diffraction gratings, polarization selecting grids, choppers, and finally absorption cavities can be incorporated without greatly affecting short-term stability performance. Short-term stabilities of at least a few parts in 10¹³can be achieved for observation times of 0.1 second.