10-Watt-Level 4.3 μm-Band Nanosecond Pulse Generation in CO ₂ -Filled Hollow-Core Fibers

A fiber-based route to mid-infrared nanosecond pulse laser generation in gas-filled hollow-core anti-resonant fiber at 4.3 m with 10-watt-level average power is demonstrated.The demonstration experiments, harnessing a single pump pulse with 37 ns duration and 125 W output power at 2 m in a CO-filled large-mode-field hollow-core anti-resonant fiber, produce nanosecond pulses centered at 4.3 m band with the output power of 10.27 W, with a pulse width of 29 ns and repetition rate of 10 MHz.Efficient high-power mid-infrared laser generation is realized by detuning the pump wavelength from the CO molecular absorption peak, leading to mitigating the gain saturation issue in the CO-filled hollow-core anti-resonant fiber laser under high-power pumping.To the best of our knowledge, this represents the highest power reported for CO-filled hollow-core fiber nanosecond pulse laser sources to date, demonstrating a 34-fold power improvement over previous works.