High Harmonic Generation from ultra-relativistic 400nm Laser Solid Interactions

We present experimental results of high harmonic generation generated by high contrast, 400 nm short pulse laser beams with solid density targets and on-target intensities of up to1021 W/cm2. Harmonic spectra were measured as a function of targets which varied in composition and thickness. Particle-in-cell simulations were performed showing the relationship between target parameters and emitted x-ray and electron beams.