New technique for measurement of upper laser level decay rates in gas laser plasmas

We have measured the axial mode competition in He-Zn II lasers at the 492.4 nm line and He-Cd II lasers at the 533.7 and 537.8 nm lines in the high-He pressure region. According to the behavior of the He pressure dependences of the axial mode competition, a new method to estimate experimentally the decay rates of the upper laser levels has been proposed. The pressure broadening effects on the total oscillation width are small, and the broadening mechanism in these lasers is inhomogeneous (rather than homogeneous) broadening.