Design and short-term stability of single-frequency CO2lasers

This paper describes a family of sealed-off, single-frequency, TEM00q-mode CO2lasers with output powers up to 15 watts. Short-term frequency stability[1],[2] measurements of the beat note of two free-running lasers in typical laboratory setups are discussed thereafter. The preliminary measurements indicate a short-term stability of about 5 parts in 10¹²for an observation time of 0.05 seconds, and about 5 parts in 10¹³, disregarding the discrete spectral lines resulting from 60-Hz modulation by power supply ripple. One or two orders-of-magnitude improvement is predicted, leading to the possibility of measuring the linewidth limit imposed by quantum noise.