Efficient multi-keV X-ray generation from high-contrast laser plasma interaction.

Kα line emission from Mo was experimentally and theoretically studied using clean, ultrahigh-intensity femtosecond laser pulses. The absolute yields of Kα x-rays at 17 keV from Mo were measured as a function of the laser pulse contrast ratio and irradiation intensity. Significantly enhanced Kα yields were obtained by employing high contrast ratio at optimum irradiance. Conversion efficiencies of 4.28 x 10^-5/sr, the highest values obtained to date, was demonstrated with contrast ratios in the range of 10^-10 to 10^-11. [ABSTRACT FROM AUTHOR]