Mid-Infrared Multispectral Gaseous Stimulated Raman Scattering Laser

Chencheng Shen,Xianglong Cai,Yuxi Jia,Jinbo Liu,Jingwei Guo,Dong Liu,Tiancheng Zheng

doi:10.3390/app112411875

Abstract

We demonstrated mid-infrared gaseous stimulated Raman scattering lasers in free space. Mixed gases of hydrogen and deuterium were used as Raman gain media in one Raman cell. Pumped by laser pulses at 1064 nm, the first Stokes Raman components at 1560 nm and 1907 nm were generated. A four-wave mixing process with the pump laser at 1064 nm and Raman lasers at 1560 nm and 1907 nm contributed to dramatically reducing the threshold of mid-IR laser generation at 4432 nm. The maximum output peak power of a mid-IR laser at 4432 nm reached 121 kW. Furthermore, by scattering on the rotational transition of deuterium, multispectral mid-IR Raman lasers at wavelengths of 2071 nm, 2266 nm, 2604 nm, 2920 nm, 3322 nm, 3743 nm, 4432 nm, and 5431 nm were also generated. Our results show that this is a convenient method to reduce the threshold and achieve a high power output with mid-IR Raman lasers.

Highlights

Gas Raman gain media in hollow-core fiber (HCF) have been demonstrated to generate mid-IR Raman lasers, but the strong loss of silica over wavelengths of 5 μm limits the generation of silica antiresonant hollow-core fiber Raman lasers [14,15,16,17,18]
We reported the generation of mid-IR multispectral gaseous Raman lasers in free space by using a mixed gas of hydrogen (H2 ) and deuterium (D2 ) as the Raman gain
We reported the generation of mid-IR multispectral gaseous Raman2 of la-8 sers in free space by using a mixed gas of hydrogen (H2) and deuterium (D2) as the Raman gain medium

Summary

Introduction

Large gain coefficients and the high thermal conductivity of solid crystals can be beneficial to realizing a high conversion efficiency with mid-IR Raman lasers. The development of high-energy Raman laser output is limited by the absorption of crystals in the mid-IR range and the low optical damage threshold. The Raman shifts of solid crystals are about 1000 cm−1 , which is not large enough to generate wide-ranging mid-IR Raman lasers. Gas Raman gain media in hollow-core fiber (HCF) have been demonstrated to generate mid-IR Raman lasers, but the strong loss of silica over wavelengths of 5 μm limits the generation of silica antiresonant hollow-core fiber Raman lasers [14,15,16,17,18]. It is very hard to generate mid-IR Raman lasers due to the low Raman gain of gaseous media

Methods

Discussion

Conclusion