Two-dimensional near-field images of the neonlike germanium soft-x-ray laser.

We present what are believed to be the first two-dimensional near-field images of the neonlike germanium x-ray laser obtained with multilayer imaging mirrors. The Asterix iodine laser, with a low-intensity prepulse 5.23 ns before the main pulse, was used to irradiate germanium slab targets. We observe a large difference in the spatial dependence of the J = 0-1 and J = 2-1 lines of germanium, with the J = 2-1 emission peaking farther away from the target surface. The prepulse level is also observed to have a significant effect on the spatial dependence of the germanium laser lines. A great deal of structure is observed in the near-field images, particularly in the J = 0-1 emission.