Enhancement of Photon Number Reflected by the Relativistic Flying Mirror

Abstract

Laser light reflection by a relativistically moving electron density modulation (flying mirror) in a wake wave generated in a plasma by a high intensity laser pulse is investigated experimentally. A counterpropagating laser pulse is reflected and upshifted in frequency with a multiplication factor of 37--66, corresponding to the extreme ultraviolet wavelength. The demonstrated flying mirror reflectivity (from $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ to $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, and from $1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ to $0.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, for the photon number and pulse energy, respectively) is close to the theoretical estimate for the parameters of the experiment.