We have studied theoretically and experimentally the x-ray production above 1 keV from femtosecond laser plasmas generated on periodically modulated surface targets. Laser energy coupling to plasma surface waves has been modeled using a numerical differential method. Almost total absorption of incident laser radiation is predicted for optimized interaction conditions. Silicon gratings have been irradiated by a 120fs Ti:sapphire laser at irradiances in excess of 1016 W/cm2. X-ray intensities above 1.5 keV (K-shell lines) have been measured as a function of the incidence angle. Results show a distinct x-ray emission maximum for the first order diffraction angle and are in good qualitative agreement with our theoretical predictions.
© 1995 Optical Society of America
J.C. Gauthier, S. Bastiani, P. Audebert, J.P. Geindre, K. Neuman, T.D. Donnelly, M. Hofer, R.W. Falcone, R.L. Sheperd, D.F. Price, W.E. White, "Femtosecond laser-produced plasma x-rays from periodically modulated surface targets," SPIE Proceedings Applications of Laser Plasma Radiation II, M. Richardson and A. Kyrala, eds, vol. 2423, pp. 242-253 (1995).