High contrast femtosecond laser-driven intense hard X-ray source for imaging application

Chen, L. M.*; Wang, W. M.*; Kando, Masaki; Hudson, L. T.*; Liu, F.*; Lin, X. X.*; Ma, J. L.*; Li, Y. T.*; Bulanov, S. V.; Tajima, Toshiki*; Kato, Yoshiaki* ; Sheng, Z. M.*; Zhang, J.*

In this report we address the current situation of laser-driven hard X-ray sources for imaging applications, especially the saturation of X-ray conversion efficiency and the serious impact upon imaging quality. By employing high contrast laser pulses, the conversion efficiency to X-rays from solid foil targets is improved and the structure of the spectrum can be optimized with respect to imaging applications. In addition, bright Ar K-shell X-rays with very little continuum background have been generated by irradiating, with an ultra-high contrast laser, a target of Ar gas clusters created by a gas jet. These improvements show great potential for single-shot ultrafast X-ray imaging.