Abstract

We have recently demonstrated quasi-cw laser action in Ca vapor following pulsed-laser excitation of the 4s4p ³P₁ metastable state.¹ The long radiative lifetime associated with a metastable state permits the collisional transfer of energy to dominate after the laser excitation. This leads to the so-called “collisional recycling" of atomic population where the effective lifetimes of some higher excited states may also be considerably prolonged.^2,3 A remarkable consequence of the collisional recycling is that population inversions, if any, may be sustained over a long period of time.¹

© 1994 IEEE