Plasma Mirrors as Optical Components for the Manipulation of Intense Light

The replacement of standard optical components with a toolkit of plasma-based optics allows the construction of compact high-peak-power laser systems. Plasma mirrors form a key part of this toolkit, permitting reflection of relativistic intensities, temporal contrast and spatial mode cleaning, and the efficient generation of harmonics of the initial laser pulse. We characterize the emission of upshifted frequencies from plasma mirrors into the relativistic regime both experimentally, with a 25 fs, 400 mJ laser system, and with particle-in-cell simulations across a broad range of parameters, showing in particular how sequences of cascaded plasma mirrors can improve beam quality and the efficiency of harmonic generation.