Light: Science & Applications (May 2024)

Ionizing terahertz waves with 260 MV/cm from scalable optical rectification

  • Hyeongmun Kim,
  • Chul Kang,
  • Dogeun Jang,
  • Yulan Roh,
  • Sang Hwa Lee,
  • Joong Wook Lee,
  • Jae Hee Sung,
  • Seong Ku Lee,
  • Ki-Yong Kim

DOI
https://doi.org/10.1038/s41377-024-01462-w
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 13

Abstract

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Abstract Terahertz (THz) waves, known as non-ionizing radiation owing to their low photon energies, can actually ionize atoms and molecules when a sufficiently large number of THz photons are concentrated in time and space. Here, we demonstrate the generation of ionizing, multicycle, 15-THz waves emitted from large-area lithium niobate crystals via phase-matched optical rectification of 150-terawatt laser pulses. A complete characterization of the generated THz waves in energy, pulse duration, and focal spot size shows that the field strength can reach up to 260 megavolts per centimeter. In particular, a single-shot THz interferometer is employed to measure the THz pulse duration and spectrum with complementary numerical simulations. Such intense THz pulses are irradiated onto various solid targets to demonstrate THz-induced tunneling ionization and plasma formation. This study also discusses the potential of nonperturbative THz-driven ionization in gases, which will open up new opportunities, including nonlinear and relativistic THz physics in plasma.