Acta Optica Sinica, Volume. 40, Issue 16, 1614001(2020)
Optically Pumped 4 μm CW HBr Gas Laser Based on Hollow-Core Fiber
An optically pumped mid-infrared HBr gas laser based on hollow-core fiber (HCF) is reported. A tunable narrow linewidth 2 μm continuous-wave thulium-doped fiber amplifier is used to pump a 4.4 m anti-resonance hollow-core fiber filled with low-pressure HBr gas. When the seed wavelength is precisely tuned to the R(2) absorption line near 1971.7 nm of hydrogen bromide isotope H 79Br, the H 79Br molecules in the vibrational ground state v0 will transit to the vibrational excited-state v2, then a population inversion will be formed between the vibrational excited states v2 and v1. Due to the transition selection rules, two transitions will simultaneously occur by the spectral lines R(2) and P(4), whose wavelengths are 3977.2 nm and 4165.3 nm, respectively. When the HBr pressure is 6.2 mbar, the maximum output power of 4 μm laser is 125 mW, and the optic-to-optic conversion efficiency is about 10% in terms of the pump light coupled into the HCF. By further improving the transmission loss spectrum of the HCF and increasing the coupling efficiency of the pump light, the laser efficiency and output power can be greatly improved, and a wide-range tunable mid-infrared laser emission could be obtained owing to the energy level characteristics of HBr molecules in the future.
Get Citation
Copy Citation Text
Zhiyue Zhou, Hao Li, Yulong Cui, Wei Huang, Zefeng Wang. Optically Pumped 4 μm CW HBr Gas Laser Based on Hollow-Core Fiber[J]. Acta Optica Sinica, 2020, 40(16): 1614001
Category: Lasers and Laser Optics
Received: Mar. 30, 2020
Accepted: May. 6, 2020
Published Online: Aug. 7, 2020
The Author Email: Wang Zefeng (zefengwang_nudt@163.com)