Multi-wavelength high-energy gas-filled fiber Raman laser spanning from 1.53  µm to 2.4  µm

Abstract

In this work, we present a high pulse energy multiwavelength Raman laser spanning from 1.53 µm up to 2.4 µm by employing the cascaded rotational stimulated Raman scattering (SRS) effect in a 5-m hydrogen (H2)filled nested anti-resonant fiber (NARF), pumped by a linearly polarized Er/Yb fiber laser with a peak power of ~13 kW and pulse duration of ~7 ns in the C-band. The developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400 nm, with pulse energies as high as 18.25 µJ, 14.4 µJ, 14.1 µJ, and 8.2 µJ, respectively. We demonstrate how the energy in the Raman lines can be controlled by tuning the H2 pressure from 1 bar to 20 bar.

2 μm Raman laser based on CO2-filled hollow-core silica fiber

“…The beam profiles are measured with a slit scanning beam profiler (BP109-IR2, Thorlabs). The ARHCF used, shown in Figure 2(a), has a nested structure, forming a hollow core region with diameter of ~37.6 µm 7 . The wall thickness and diameter are 406 nm and 22.2 µm for the outer capillaries, 621 nm and 6.04 µm for the nested (inner) capillaries, respectively.…”

“…However, the nonlinear effects (e.g., stimulated Brillouin/Raman scattering, nonlinear spectrum broadening), amplified spontaneous emission (ASE) and thermal damage are detrimental and unavoidable factors for the generation of narrow linewidth and high energy laser pulses 3,4 . The advent of gas-filled hollow-core fiber (HCF) Raman laser technology provides an alternative solution [5][6][7] . This laser technology relies on gas as the active gain medium, thus offering important advantages such as low nonlinearity and high damage threshold, while the relatively high threshold of SRS can effectively suppress the ASE frequency conversion 6,[8][9][10][11] .…”

Stimulated Raman lineshapes in the large light-matter interaction limit

“…For these reasons Raman gains and Raman losses are measured in the red and in the blue side of the SRS spectrum [24], respectively. In parallel with microscopy and spectroscopy, technological applications based on SRS have been explored with the aim to realize Raman-based lasers [25][26][27][28][29], frequency shifters [30,31] and Raman amplifiers [32,33]. Inelastic scattering of electromagnetic radiation provides indeed a convenient method to synthesize and amplify ultrashort laser pulses, which is in general a challenging task, with a unique versatility.…”

Ultraviolet to mid-infrared gas-filled anti-resonant hollow-core fiber lasers

“…In these reports, the quantum efficiency can easily reach a desirable level (e.g., >60%), leading to high pulse energies in micro-joule range. Multiwavelength (or frequency comb-like) Raman lasers due to cascaded (anti-) Stokes effects have also been reported 9,18,[20][21][22] , which have versatile applications such as sensing, wavelength division multiplexing communication, and optical signal processing 23 . In comparison with the conventional method of selecting multiple wavelengths with a comb filter within the limited gain bandwidth of a rare-earth ion-doped gain medium 24 , this method can achieve multi-wavelength operation in a much broader wavelength range.…”