Stark cell noise reduction of a CO2laser beam

A technique is demonstrated for reducing the rapid intensity fluctuations in the beam of a single frequency, polarized CO
2
laser tuned to the
P(20)
transition at 10.6 μm. The method uses a Stark-tunable absorption line in NH
2
D to compensate for the fluctuations of the laser output. Substantial reductions in laser beam intensity noise have been obtained. The method may be applied to other lines of the CO
2
laser and indeed to other types of lasers.