Spatially resolved gain measurements of a slab type RF excited CO2 laser

Spatially resolved small signal gain in a slab type radio frequency (RF) di scharge excited CO2 laser medium was analyzed in order to observe the effec t of the plasma sheath region near the slab electrodes. Choosing four lines of 10.6 mu m transition such as P(14), P(20), P(26) and P(30), we measured each gain with a resolution of 0.1 mm using a digital beam profiling syste m based on a two-dimensional pyro-electric infrared detector array. As a re sult, the gain was found to have a peak value of 0.4%/cm at the center of t he gap between the electrodes, which was reduced to approximately half in t he sheath region. Gas temperature (rotation temperature of CO2) was calcula ted to be 400 K at the center and it increased to 600 K in the sheath regio n.