Relativistic high harmonic generation in gas jet targets

A. S. Pirozhkov, M. Kando, T. Zh Esirkepov, P. Gallegos, H. Ahmed, E. N. Ragozin, A. Ya Faenov, T. A. Pikuz, T. Kawachi, A. Sagisaka, J. K. Koga, M. Coury, J. Green, P. Foster, C. Brenner, B. Dromey, D. R. Symes, M. Mori, K. Kawase, T. KameshimaY. Fukuda, L. M. Chen, I. Daito, K. Ogura, Y. Hayashi, H. Kotaki, H. Kiriyama, H. Okada, N. Nishimori, T. Imazono, K. Kondo, T. Kimura, T. Tajima, H. Daido, P. Rajeev, P. McKenna, M. Borghesi, D. Neely, Y. Kato, S. V. Bulanov

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

Abstract

We experimentally demonstrate a new regime of high-order harmonic generation by relativistic-irradiance lasers in gas jet targets. Bright harmonics with both odd and even orders, generated by linearly as well as circularly polarized pulses, are emitted in the forward direction, while the base harmonic frequency is downshifted. A 9 TW laser generates harmonics up to 360 eV, within the 'water window' spectral region. With a 120 TW laser producing 40 uJ/sr per harmonic at 120 eV, we demonstrate the photon number scalability. The observed harmonics cannot be explained by previously suggested scenarios. A novel high-order harmonics generation mechanism [T. Zh. Esirkepov et al., AIP Proceedings, this volume], which explains our experimental findings, is based on the phenomena inherent in the relativistic laser - underdense plasma interactions (self-focusing, cavity evacuation, and bow wave generation), mathematical catastrophe theory which explains formation of electron density singularities (cusps), and collective radiation due to nonlinear oscillations of a compact charge.

Original languageEnglish
Title of host publicationLaser-Driven Relativistic Plasmas Applied to Science, Energy, Industry, and Medicine
Subtitle of host publicationThe 3rd International Symposium
EditorsSergei V. Bulanov, Atsushi Yokoyama, Yuri I. Malakhov, Yasumasa Watanabe
Place of PublicationMelville, NY
Pages167-171
Number of pages5
DOIs
Publication statusPublished - 11 Jul 2012
Event3rd International Symposium on Laser-Driven Relativistic Plasmas Applied to Science, Energy, Industry, and Medicine - Kyoto, Japan
Duration: 30 May 201130 May 2011

Publication series

NameAIP Conference Proceedings
PublisherAIP
Volume1465

Conference

Conference3rd International Symposium on Laser-Driven Relativistic Plasmas Applied to Science, Energy, Industry, and Medicine
CountryJapan
CityKyoto
Period30/05/1130/05/11

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Keywords

  • coherent X-rays
  • electron spikes
  • high-order harmonics
  • relativistic laser plasma

Cite this

Pirozhkov, A. S., Kando, M., Esirkepov, T. Z., Gallegos, P., Ahmed, H., Ragozin, E. N., ... Bulanov, S. V. (2012). Relativistic high harmonic generation in gas jet targets. In S. V. Bulanov, A. Yokoyama, Y. I. Malakhov, & Y. Watanabe (Eds.), Laser-Driven Relativistic Plasmas Applied to Science, Energy, Industry, and Medicine: The 3rd International Symposium (pp. 167-171). (AIP Conference Proceedings; Vol. 1465). Melville, NY. https://doi.org/10.1063/1.4737557