TRANSIENT ABSORPTION AND ITS INFLUENCE ON ENERGY EXTRACTION IN A DISCHARGE-PUMPED F2 LASER

Small-signal transient absorption of a discharge-pumped F-2 laser (157.6 nm) medium was measured by using a Raman-shifted F-2 laser (168.6 nm). The small-signal total absorption was obtained for 6 atm laser media at an excitation rate of similar to 26 MW/cm(3), where a small-signal net gain was independently measured to similar to 35%/cm, as the sum of a transient absorption of similar to 2.5%/cm and a stationary absorption of similar to 0.5%/cm. In spite of the relatively large gain-to-loss ratio a significantly low maximum laser intensity of similar to 2 MW/cm(2), which gives zero extraction efficiency in the F-2 laser medium, measured in heavily saturated F-2 laser amplification experiments, suggests that the energy extraction is limited by additional absorption.