Ultrahigh intensities and contrast using an ellipsoidal plasma mirror with the Z-Backlighter Laser

Plasma-based focusing optics have been proven to increase the peak intensity of ultrahigh intensity lasers without significantly distorting the beam spatial profile or modifying the laser system itself [1]. In this experiment we will make use of an ellipsoidal plasma mirror (EPM) to increase the contrast and decrease the focal size of the ultrashort pulses provided by the Z-Backlighter Laser at Sandia National Laboratories. We predict the EPM setup to reduce the effective numerical aperture from f/3 to f/0.6, which could lead to a 25-fold intensity enhancement compared to flat plasma mirrors. These increased intensities will be demonstrated by observing protons accelerated from laser-plasma interactions via the target normal sheath acceleration mechanism. We expect protons with energies of more than 50 MeV to be generated. \\[4pt] [1] Nakatsutsumi \textit{et al}. Fast focusing of short-pulse lasers by innovative plasma optics toward extreme intensity. Optics Lett. \textbf{35}, 2314 (2010).