Dynamic Wavelength Selection of 1, 1.5, and 1.9 μm via Gas Switching in Hollow-Core Fiber

We generate 1.5 μm and 1.9 μm light through stimulated Raman scattering by coupling a 1 μm laser to a single mode broadband antiresonant hollow core fiber filled with methane or hydrogen. Maximum quantum conversion efficiencies of 91% for 1.5 μm and 38% for 1.9 μm are demonstrated for 120 psi of methane in a 10-m fiber and 400 psi of hydrogen in a 1-m fiber. The dynamics of gas pressurization in hollow-core fiber are investigated for two different fiber lengths and filling architectures. A gas switching cycle is completed in 40 minutes in a 1-m fiber filled from both ends. The setup functions as an efficient high peak-power source that can be switched between three major rare-earth laser emission bands of ytterbium (1 μm), erbium (1.5 μm), and thulium (1.9 μm).