Demonstration of flying mirror with improved efficiency

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Fukuda, Yuji; Chen, L.-M.*; Daito, Izuru; Ogura, Koichi; Homma, Takayuki; Hayashi, Yukio; Kotaki, Hideyuki; Sagisaka, Akito; Mori, Michiaki; Koga, J. K.; Kawachi, Tetsuya; Kiriyama, Hiromitsu; Okada, Hajime; Kawase, Keigo; Kameshima, Takashi; Nishimori, Nobuyuki; Ragozin, E. N.*; Faenov, A. Y.; Pikuz, T. A.*; Kimura, Toyoaki*; Tajima, Toshiki; Daido, Hiroyuki; Kato, Yoshiaki* ; Bulanov, S. V.

A strongly nonlinear breaking wake wave driven by an intense laser pulse can act as a partially reflecting relativistic mirror (the Flying Mirror). Upon reflection from such mirror, a counter-propagating optical-frequency laser pulse is directly converted into high-frequency radiation, with a frequency multiplication factor (the double Doppler effect). We present the results of recent experiment in which the photon number in the reflected radiation was more than times larger than in our proof-of-principle experiment. It is notable that the energy of laser was increased about three times. The Flying Mirror promises to generate intense coherent ultrashort XUV and X-ray pulses that inherit their temporal shape and polarization from the original optical-frequency (laser) pulses. Furthermore, the reflected radiation bears important information about the reflecting wake wave itself, which can be used for the diagnostics.