Measurement of0.35μmLaser Imprint in a Thin Si Foil Using an X-Ray Laser Backlighter

Imprinted modulations in optical depth of a thin Si foil due to 0.35 μm laser irradiation at about $3\times {10}^{12}$ W/c${\mathrm{m}}^2$ have been measured at shock breakout. These measurements were made by high resolution face-on radiography using a gain saturated yttrium x-ray laser backlighter operating at a wavelength of 15.5 nm with a multilayer optics imaging system. The imprinted modulation due to a static speckle pattern and a 0.29 and a 0.33 THz spectral dispersion smoothed speckle pattern were studied. Comparison of the imprinted modulation is made with simulations.