Low-energy pumping of a 108.9-nm xenon Auger laser

We report extensive measurements of gain in the Xe III system initially observed by Kapteyn et al. [Phys. Rev. Lett. 57, 2939 (1986)]. The dependence of this gain on pressure, pumping-pulse length, and pump energy is presented. By optimizing these parameters we have achieved a gain of exp(3.2) by using only 0.56 J of 1064-nm energy on target, representing an efficiency improvement of nearly 100. Total gains as high as exp(6.6) have been measured when using higher energies. Our data indicate that effective laser-produced plasmas can be created with applied power densities as low as 5 x 10(10) W cm(-2).