MEASUREMENT OF SPATIAL GAIN DISTRIBUTION FOR A NEON-LIKE GERMANIUM 19.6-NM LASER

We measure the transverse spatial distribution of the gain region for the 19.6-nm neonlike germanium laser line by use of a short amplifier, which is backlit by a longer laser, both of which are created by illu mination of a germanium slab target with a series of short 100-ps puls es from the Nova laser. The backlighting technique enables us to reduc e greatly the refraction effects that dominated previous imaging exper iments and made direct gain measurements impossible. Measurements are made with a two-dimensional high-resolution spatial-imaging diagnostic , and simulations of the gain are compared with experiments. (C) 1997 Optical Society of America.