IEEE Access (2020-01-01)

Actively Q-Switching in the Intra-Cavity Pumping Mechanism for Polarized Oscillation at 2.1 <italic>&#x03BC;</italic>m

  • Haizhou Huang,
  • Huawen Hu,
  • Yan Ge,
  • Hongchun Wu,
  • Jinhui Li,
  • Huagang Liu,
  • Wenxiong Lin

DOI
https://doi.org/10.1109/ACCESS.2020.3024074
Journal volume & issue
Vol. 8
pp. 180255 – 180260

Abstract

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Q-switched and polarized Ho lasers are the ideal driving source for mid-infrared radiation via optical parametric oscillation. Although intra-cavity pumping is an efficient way to achieve the Ho laser oscillation at 2.1 μm, which also facilitates the direct use of common diodes in a compact structure, it was demonstrated to be not suitable for Q-switching due to the saturable effect of the Ho-doped gain medium. Here, we report a RbTiOPO4 Q-switched intra-cavity pumped laser via integrating the Tm-doped and Ho-doped gain medium into a composite structure and decoupling the Tm laser from the Ho laser before it was modulated by the RbTiOPO4 crystal. The shortest pulse of 41 ns at repetition frequency of 1 kHz was obtained with a peak power of 7.5 kW. By competing with the intensified self-pulsing, the maximum pulse repetition frequency was found to reach 7 kHz, which was half the driving frequency of the electro-optical modulator. The results pave the way for achieving regular pulses from the intra-cavity pumping mechanism, which facilities a compact, accessible and robust pulse source at 2.1 μm.

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