CC BY
14ALT'22
NONLINEAR AND TERAHERTS PHOTONICS
THz-I-13
THz generation in multi-terawatt laser plasma
M. M. Nazarov1, P. A. Shcheglov1, M. V. Chaschin1, A.A.Tausenev1,2, A.A. Garmatina1, A.V.Mitrofanov1'3,
D. A. Sidorov-Biryukov1'2'3.
1 - Kurchatov Institute National Research Center, Moscow 123182, Russia 2 - Physics Department, M.V. Lomonosov Moscow State University, Moscow 119992, Russia 3 - Russian Quantum Center, Skolkovo, Moscow Region 143025, Russia Nazarov email address: nazarovmax@mail.ru
Powerful THz pulses are requested for the novel area of nonlinear optics in THz range, for accelerating charged particle bunches, for time-resolved experiments on matter manipulation. High-power THz radiation could be obtained from tera- and peta-watt class Ti:sapphire lasers if the problems of saturation and breakdown of materials were solved. One of the media free from saturation problems for conversion into THz at relativistic intensity and multiterawatt pulses is a metal foil (and a dense plasma above it surface). The other media is low-dense plasma in a low-pressure gas discharge, which is efficient and well studied for subterawatt, two-color pulses p].
We experimentally compare the maximum energy of the obtained THz radiation in these two cases. To characterize the spatiotemporal dimensions of the plasma above the metal and the actual laser intensity, optical harmonics and X-ray radiation from the Cu target are also measured, which correlate with the THz output [2]. The observed effect of the foil thickness on the yield of all secondary radiation indicates the contribution of recirculating hot electrons in the thin foil [3]. While no saturation of the THz radiation output from the metal was observed up to intensities of 1018 W/cm2, the resulting energy of 0.2 ^J is still less than in the case of THz generation in a low-pressure gas under two-color pumping. High-power THz pulses with an energy of 4 ^J and a spectral width of up to 6 THz obtained in the gas case unfortunately completely saturates at laser energies above 40 mJ under any optimization of the parameters of laser irradiation. The prospects of metal as a medium for conversion of laser pulses with energies of 0.5-7 J into THz is discussed. In addition, the spectrally bright Cu Ka X-ray radiation, which is best generated at subrelativistic intensity, is used for diffraction, that is, diagnostics with angstrom spatial resolution, all with femtosecond time resolution.
The work is partly supported by Ministry of Science and Higher Education of the Russian Federation in framework of Agreement No. 075-15-2022-830 and partly by RFBR grant N 20-21-00140.
Концевые сноски
1 М. М. Nazarov, A. V. Mitrofanov, D. A. Sidorov-Biryukov, et.al. JIMTW, 1-13.(2020).
2 M. M. Nazarov, P. A.Shcheglov, M. V. Chaschin, et.al. JPCS, 1692, 012018, (2020).
3 M. M. Nazarov, P. A.Shcheglov, A. A.Garmatina, et.al. Quant.Electron. in print, (2022).
