Enhanced Kα output of Ar and Kr using size optimized cluster target irradiated by high-contrast laser pulses

We observed that increasing the clusters size and laser pulse contrast can enhance the X-ray flux emitted by femtosecond-laser-driven-cluster plasma. By focusing a high contrast laser (10(-10)) on large argon clusters, high flux K-alpha-like X-rays (around 2.96 keV) is generated with a total flux of 2.5 x 10(11) photons/J in 4 pi and a conversion efficiency of 1.2 x 10(-4). In the case of large Kr clusters, the best total flux for L-shell X-rays is 5.3 x 10(11) photons/J with a conversion efficiency of 1.3 x 10(-4) and, for the K-alpha X-ray (12.7 keV), it is 8 x 10(8) photons/J with a conversion efficiency of 1.6 x 10(-6). Using this X-ray source, a single-shot high-performance X-ray imaging is demonstrated. (C) 2011 Optical Society of America