Ultrafast Science (Jan 2024)

Multiple-Photon Resonance Enabled Quantum Interference in Emission Spectroscopy of

  • Xiang Zhang,
  • Qi Lu,
  • YaLei Zhu,
  • Jing Zhao,
  • Rostyslav Danylo,
  • Liang Xu,
  • Mingwei Lei,
  • Hongbing Jiang,
  • Chengyin Wu,
  • Zhedong Zhang,
  • Aurélien Houard,
  • Vladimir Tikhonchuk,
  • André Mysyrowicz,
  • Qihuang Gong,
  • Songlin Zhuang,
  • Zengxiu Zhao,
  • Yi Liu

DOI
https://doi.org/10.34133/ultrafastscience.0051
Journal volume & issue
Vol. 4

Abstract

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Quantum interference occurs frequently in the interaction of laser radiation with materials, leading to a series of fascinating effects such as lasing without inversion, electromagnetically induced transparency, Fano resonance, etc. Such quantum interference effects are mostly enabled by single-photon resonance with transitions in the matter, regardless of how many optical frequencies are involved. Here, we report on quantum interference driven by multiple photons in the emission spectroscopy of nitrogen ions that are resonantly pumped by ultrafast infrared laser pulses. In the spectral domain, Fano resonance is observed in the emission spectrum, where a laser-assisted dynamic Stark effect creates the continuum. In the time domain, the fast-evolving emission is measured, revealing the nature of free-induction decay arising from quantum radiation and molecular cooperativity. These findings clarify the mechanism of coherent emission of nitrogen ions pumped with mid-infrared pump laser and are found to be universal. The present work opens a route to explore the important role of quantum interference during the interaction of intense laser pulses with materials near multiple photon resonance.