HIGH REPETITIVE PLASMA X-RAY SOURCE PRODUCED BY A ZIGZAG SLAB LASER

Some properties of laser-generated plasma emission in the soft x-ray region (0.1 keV<hν<1.5 keV) are presented. Detailed spectral distributions are reported for several kinds of materials (carbon, aluminum, titanium, copper, zinc, molybdenum, tin, tungsten, and lead). Dependence of x-ray emission on focal size and target thickness is also studied. The experiments were carried out at a laser intensity of a few times 1012 W/cm 2 using Nd-doped phosphate zigzag glass slab laser (8 J/40 ns, λ=1.054 μm). As an application of the laser-generated plasma x rays, the sensitivity of FBM-120 resist for x-ray lithography was measured and a 0.25-μm-wide space mask pattern was replicated.