<title>Gain measurement of TEA-CO<formula><inf><roman>2</roman></inf></formula> laser with supersonic gas flow</title>

Abstract

A TEA-CO2 laser with a supersonic gas flow has been developed, and the small-signal gain of a laser medium is measured. During the generation of the supersonic gas flow, the laser medium is cooled by the adiabatic expansion through a supersonic nozzle. Since excited CO2 molecules in the cooled laser medium are concentrated within a specific range of the rotational quantum numbers J, the laser output and its wavelength should be changed by the cooling. An investigation is conducted with a single-pulse excitation discharge in the laser medium flowing at Mach number 2. The laser medium is cooled to 133 K under this condition. It is found that the breakdown voltage, the current, and the power density of the excitation discharge are estimated to be 22 kV, 3.8 kA, and 1.2 MW/cm3, respectively. The small-signal gain for this cooled laser medium is measured to be 2.2 %/cm, which is 1.3 times as high as that obtained for the laser medium at room temperature. It suggests that the TEA-CO2 laser with a supersonic gas flow has a potential for higher laser output. We also find that the wavelength for the maximum gain is 10.494 μm (J = 10) at 133 K, while is 10.551 μm (J = 16) at room temperature.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.