Enhanced four-wave mixing in a hollow-core photonic-crystal fiber

摘要

Hollow-core photonic-crystal fibers are shown to substantially enhance four-wave mixing (FWM) of laser pulses in a gas filling the fiber core. Picosecond pulses of Nd:YAG fundamental radiation and its second harmonic are used to generate a signal at the frequency of the third harmonic by the FWM process 3ω=2ω+2ω-ω. The efficiency achieved for this process in a 9-cm-long, 13-μm-hollow-core-diameter photonic-crystal fiber, designed to simultaneously transmit a two-color pump and the FWM signal, is shown to be ～800 times higher than the maximum FWM efficiency attainable with the same laser pulses in the tight-focusing regime.