Efficient diode-pumped mid-infrared emission from acetylene-filled hollow-core fiber.

We report 3.1-3.2 μm mid-infrared emission from acetylene-filled low loss antiresonant hollow-core fiber pumped with an amplified, modulated, narrowband, tunable 1.5 μm diode laser. The maximum power conversion efficiency of ~30%, with respect to the absorbed pump power, is obtained with a 10.5 m length of fiber at 0.7 mbar. The maximum efficiency with respect to the total incident pump power (~20%) and the minimum pump laser energy required (<50 nJ) are both improved compared to similar work reported previously using an optical parametric oscillator as a pump source. This paper provides an effective route to obtain compact mid-infrared fiber lasers.