Small signal gain of the hollow-cathode Cd-He laser

Experimental results are presented on variations of the small signal gain as a function of discharge current and He pressure for the 533.7 and 537.8 nm lines of Cd II in a hollow-cathode Cd-He laser. Spontaneous emission measurements in a direction normal to the laser axis allow the dominant line broadening type to be determined. Measurement of total power extracted from the cavity by simultaneous monitoring of the laser output and window reflection make it possible to calculate transmission coefficient. The small signal gain coefficient varies linearly with discharge current, suggesting the possibility of obtaining high laser output at high discharge current.