Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion

TL;DR

This paper reports the first experimental observation of mid-infrared dispersive waves generated in gas-filled hollow-core photonic crystal fibers due to transient ionization-induced changes in dispersion, enabling broader supercontinuum spectra.

Contribution

It demonstrates experimentally that transient ionization in gas-filled PCFs can produce phase-matched mid-infrared dispersive waves, expanding supercontinuum generation capabilities.

Findings

Observed mid-infrared dispersive waves in gas-filled PCF

Achieved a supercontinuum spanning 4.7 octaves

Generated up to 1.7 W of average power in the supercontinuum

Abstract

Gas-filled hollow-core photonic crystal fibre (PCF) is being used to generate ever wider supercontinuum spectra, in particular via dispersive wave (DW) emission in the deep and vacuum ultraviolet, with a multitude of applications. DWs are the result of the resonant transfer of energy from a self-compressed soliton, a process which relies crucially on phase matching. It was recently predicted that, in the strong-field regime, the additional transient anomalous dispersion introduced by gas ionization would allow phase-matched DW generation in the mid-infrared (MIR)-something that is forbidden in the absence of free electrons. Here we report for the first time the experimental observation of such MIR DWs, embedded in a 4.7-octave-wide supercontinuum that uniquely reaches simultaneously to the vacuum ultraviolet, with up to 1.7 W of total average power.