Phase-matched four-wave mixing and sensing of water molecules by coherent anti-Stokes Raman scattering in large-core-area hollow photonic-crystal fibers

Abstract

Phase-matched four-wave mixing is demonstrated for millijoule nanosecond pulses guided by photonic bandgaps of hollow fibers with a two-dimensionally periodic cladding and a core diameter of ∼50µm. Raman resonances related to the stretching vibrations of water molecules inside the hollow fiber core are detected in the spectrum of the four-wave mixing signal, suggesting phase-matched coherent anti-Stokes Raman scattering in hollow photonic-crystal fibers as a convenient sensing technique for condensed-phase species adsorbed on the inner fiber walls and trace gas detection.