Resonance-free deep ultraviolet to near infrared supercontinuum generation in a hollow-core antiresonant fibre

TL;DR

This paper demonstrates a resonance-free supercontinuum spanning from deep ultraviolet to near infrared in an antiresonant hollow-core fibre, overcoming previous limitations caused by high-loss resonance bands.

Contribution

It introduces a novel fabrication of a hollow-core fibre with a specific wall thickness to achieve continuous supercontinuum generation across a broad spectrum.

Findings

Successful generation of supercontinuum from deep UV to near IR

Resonance-free guidance achieved by specific fibre design

Dispersion landscape limits spectral broadening

Abstract

Supercontinuum generation in the ultraviolet spectral region is challenging in solid-core optical fibres due to solarization and photodarkening. Antiresonant hollow-core fibres have overcome this limitation and have been shown to guide ultraviolet light at sufficient intensity for ultraviolet spectral broadening through nonlinear optics in the filling gas. However, their ultraviolet guidance is usually limited by discontinuities caused by the presence of high-loss resonance bands. In this paper, we report on resonance-free supercontinuum generation spanning from the deep ultraviolet to the near infrared achieved through modulation instability in an argon-filled antiresonant hollow-core fibre. The fibre was directly fabricated using the stack-and-draw method with a wall thickness of approximately 90 nm, enabling continuous spectral coverage from the deep ultraviolet to the near infrared. We also report numerical simulations to investigate the supercontinuum bandwidth and the factors limiting it, finding that the overall dispersion landscape, and associated group-velocity matching of cross-phase modulation interactions, is the dominant constraint on spectral extension.