Efficient Mid-IR lasing in gas-filled hollow waveguides

Mid-IR lasers operating at 3–3.2 μm and 4.3–4.4 μm with efficiencies near 20% have been demonstrated from ¹²C2H2 and HCN-filled low-loss (< 5 dB/m) kagome-structure HC-PCF and from CO-filled silver coated capillaries.