X-ray generation in cryogenic targets irradiated by 1 μm pulse laser

Soft x-ray spectral radiations from Xe, H2O, and CO2 cryogenic targets irradiated by a 1 mu m neodymium doped YAG-slab laser at pulse widths of 12-20 ns and at laser intensities of 5 x 10(10)-10(12) W/cm(2) have been observed, These targets radiate soft x-rays in a wavelength range of 10-13 nm which is useful for projection microlithography. We have found a strong x-my spectral peak at lambda = 10.8 nm with a Xe cryogenic target. The measured x-ray conversion efficiency with the Xe target was 0.8%/sr(lambda = 10.8+/-0.27 nm) at a laser intensity of 1 x 10(12) W/cm(2). This was ten times or more efficient than that with H2O and CO2 targets. (C) 1998 American Institute of Physics.