Relativistic tennis using flying mirror

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Ma, J.-L.; Fukuda, Yuji; Chen, L. M.; Daito, Izuru; Ogura, Koichi; Homma, Takayuki; Hayashi, Yukio; Kotaki, Hideyuki; Sagisaka, Akito; Mori, Michiaki; Koga, J. K.; Kawachi, Tetsuya; Daido, Hiroyuki; Bulanov, S. V.; Kimura, Toyoaki; Kato, Yoshiaki ; Tajima, Toshiki

We present the results of the proof-of-principle experiment for frequency upshifting of the laser pulse reflected from the flying mirror. Experimentally, the wake wave is created by a 2 TW, 76 fs Ti:S laser pulse (JLITE-X) in helium plasma cm. The incidence angle of the second laser pulse on the flying mirror is 45, and the frequency upshifting factor is . The reflected signal is observed with a grazing-incidence spectrograph in 24 shots. ( nm, frequency upshifting factors =55-115, ). The reflected signal contains at least photons/sr. This effect can be used to generate coherent high-frequency ultrashort pulses that inherit temporal shape and polarization from the original (low-frequency) ones. Apart from this, the reflected radiation contains important information about the wake wave itself, e. g. location, size, phase velocity, etc.