Stark-tuned, far-infrared laser for high-frequency plasma diagnostics.

A Stark-tuned optically pumped far-infrared CH(3)OH laser operating at 119 microm has been built. The laser is designed to operate at high power while exhibiting a well-separated Stark doublet. At a pump power of 65 W and an electric field of 1 kV/cm the laser has delivered over 100 mW cw while exhibiting a frequency splitting of 34 MHz. These parameters indicate that this laser would be suitable for use in the present generation of modulated interferometers on large thermonuclear plasma devices. The achieved modulation frequency is more than an order of magnitude higher than could be achieved by using standard techniques.