Gas‐temperature measurement in pulsed H2O laser discharges

摘要

A spectroscopic technique of temperature measurement with submicrosecond time resolution, using ultraviolet OH emission, is described. The time varying gas temperature was measured during a 4‐μsec 150‐A current pulse through H2O. The gas temperature rose to 2000°K during the current pulse in pure H2O but to only 550°K in H2OHe discharges. The 2ν2 mode, which contains several lower laser levels, is pumped due to the gas heating. This tends to switch off the gain, attenuate the laser pulse, and make the medium lossy in the afterglow. Helium alleviates these problems by maintaing a low gas temperature.