XUV and IR electromagnetic radiation from nonlinear laser-plasma interaction

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

Electromagnetic wave generation at the extreme ultraviolet (XUV) and infrared (IR) wavelength range is described through the interaction of intense short laser pulses with underdense plasmas. XUV pulses are generated through a laser light reflection from a relativistically moving electron dense shells (flying mirrors). A proof-of-principle and an advanced experiment of flying mirrors are presented. Both of the experiments demonstrated light reflection and frequency upshift in the XUV wavelength range (14-20 nm). The advanced experiment with a head-on collision of two laser pulses exhibited the high reflected photon number. IR radiation, which is observed in the forward direction, has the wavelength of 5 m and the same polarization as the driving laser dominantly. The source of the IR radiation is attributed to emission from relativistic solitons formed in underdense plasma.