MAGNETIC-FIELD DIP MEASUREMENTS ON THE He–Cd LASER

Abstract

We have measured the width of the zero‐magnetic‐field power dip for the 4416‐Å transition of the He–Cd laser. The width is proportional to the decay rate of the electric quadrupole moment, ${\gamma }_a^{\text{(2)}}$ , of the upper laser level. ${\gamma }_a^{\text{(2)}}$ , which is of the order of 1 MHz, was found to vary linearly with He pressure. This variation is attributed to M_J‐mixing collisions with He atoms. The value of the ``alignment'' cross section ${\sigma }_{\mathrm{He}}^{\text{(2)}}$ is estimated from the slope of this pressure dependence. The decay rate was also found to depend on the Cd density in the discharge. This dependence is tentatively attributed to deexcitation and M_J‐mixing collisions with electrons.