High-average-power, high-repetition-rate tunable terahertz difference frequency generation with gase crystal pumped by 2 μm dual-wavelength intracavity KTP optical parametric oscillator

Dexian Yan, Yuye Wang, Degang Xu, Pengxiang Liu, Chao Yan, Jia Shi, Hongxiang Liu, Yixin He, Longhuang Tang, Jianchen Feng, Jianqin Guo, Wei Shi, Kai Zhong, Yuen Hong Tsang, Jianquan Yao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

35 Citations (Scopus)


We have demonstrated a high-average-power, high-repetition-rate optical terahertz (THz) source based on difference frequency generation (DFG) in the GaSe crystal by using a near-degenerate 2 μm intracavity KTP optical parametric oscillator as the pump source. The power of the 2 μm dual-wavelength laser was up to 12.33 W with continuous tuning ranges of 1988.0–2196.2 nm/2278.4–2065.6 nm for two waves. Different GaSe cystal lengths have been experimentally investigated for the DFG THz source in order to optimize the THz output power, which was in good agreement with the theoretical analysis. Based on an 8 mm long GaSe crystal, the THz wave was continuously tuned from 0.21 to 3 THz. The maximum THz average power of 1.66 μW was obtained at repetition rate of 10 kHz under 1.48 THz. The single pulse energy amounted to 166 pJ and the conversion efficiency from 2 μm laser to THz output was 1.68 × 10−6. The signal-to-noise ratio of the detected THz voltage was 23 dB. The acceptance angle of DFG in the GaSe crystal was measured to be 0.16°.
Original languageEnglish
Pages (from-to)82-87
Number of pages6
JournalPhotonics Research
Issue number2
Publication statusPublished - 1 Apr 2017


  • Infrared and far-infrared lasers
  • Infrared, far
  • Nonlinear optics, parametric processes
  • Nonlinear wave mixing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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