A CW 28 ?m water vapor laser for plasma diagnostics

Abstract

A high-power CW 27.972 μm water vapor laser has been constructed in order to use as a light source of an interferometer for plasma diagnostics. The laser consists of 220 cm length and 2.0 cm small bore Pyrex glass discharge tube, semi-confocal resonator and Michelson coupler. From the measurement of cavity detuning curves, it is found that two waveguide modes, EH11 and EH21 oscillate. The increase of the output power is found to become more than seven times larger by adding He(50%)−H2(50%) mixed gas. Under the optimum condition, the maximum output power of 65 mW or the output power per unit cavity volume of 83 μW/cm3 is obtained.