Efficient petawatt beam redirection for GeV class laser plasma accelerated electron beams using thin film liquid crystal plasma mirrors*

State-of-the-art laser-plasma accelerators (LPA's) can routinely produce GeV electron beams. Further development of this technology requires better control of the petawatt beam near the LPA, including beam redirection into and out of the electron beamline via ultrathin plasma mirrors. Here we report on an experiment done at the BELLA PW facility that achieved 94{\%} attenuation via beam redirection and absorption using \textasciitilde 30 nm thick liquid crystal plasma mirrors. Liquid crystal films were formed in situ on-demand and successfully used to protect an active plasma lens placed about 20 cm downstream. Additionally, emittance degradation arising from well-known Coulomb scattering interactions is intrinsically suppressed due to the nm scale thicknesses of the films. We describe the device capabilities and associated diagnostics developed, film survival tests in the LPA environment, and the transmittance as a function of intensity. We describe a simple model of plasma mirror performance at high intensities.