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High-Energy Two-Color Terahertz Generation

ORAL

Abstract

A laser pulse composed of a fundamental and properly phased second harmonic exhibits an asymmetric electric field that can drive a time-dependent current of photoionized electrons. The current produces a near-single-cycle burst of terahertz radiation. Experiments using ~1-TW ultrashort laser pulses observe optimal THz energies (~10-mJ) when the “two-color” pulse undergoes filamentary propagation in low-pressure gas1. Here we use simulations to investigate the optimal conditions for two-color THz generation driven by >100-TW ultrashort laser pulses. Simple scalings indicate that the number of photoionized electrons is independent of gas pressure. As a result, use of a low-pressure, small nonlinear refractive index, high-ionization-potential gas such as helium can mitigate multiple filamentation of the high-power pulse while strengthening the field experienced by electrons at the instant of ionization, thereby increasing the current and THz energy. A high-energy (~1-mJ), THz source driven by >100-TW pulses would enable access to a novel physics regime in which bound electron nonlinear optics and relativistic plasma physics coexist.

1Y.-J. Yoo, D. Jang, and K.-Y. Kim, Opt. Express 27, 22,663 (2019).

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Presenters

  • Tanner T Simpson

    University of Rochester

Authors

  • Tanner T Simpson

    University of Rochester

  • Jeremy Pigeon

    Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, University of Rochester Laboratory for Laser Energetics

  • Mervin Lim Pac Chong

    Laboratory for Laser Energetics, U. of Rochester

  • Robert Boni

    Lab for Laser Energetics, Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, University of Rochester

  • Dillon Ramsey

    Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, University of Rochester, Laboratory for Laser Energetics, Rochester, New York, 14623, USA

  • Kathleen Weichman

    Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, University of Rochester, Laboratory for Laser Energetics, Rochester, New York, 14623, USA

  • Dustin Froula

    University of Rochester, Laboratory for Laser Energetics, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, University of Rochester

  • John P Palastro

    Laboratory for Laser Energetics, University of Rochester, Laboratory for Laser Energetics, Rochester, New York, 14623, USA, Laboratory for Laser Energetics, University of Rochester, University of Rochester