Narrowband vacuum ultraviolet light via cooperative Raman scattering in dual-pumped gas-filled photonic crystal fiber

TL;DR

This paper presents a novel, compact method for generating narrowband, tunable vacuum ultraviolet light using dual-pumped hydrogen-filled photonic crystal fiber, enabling accessible VUV sources for diverse scientific fields.

Contribution

It introduces a new dual-pumped Raman scattering technique in gas-filled fiber to produce tunable VUV light with narrow linewidths, advancing compact and cost-effective VUV sources.

Findings

Generated VUV light down to 141 nm with 100 mW power

Achieved narrowband, tunable VUV spectrum via cooperative Raman scattering

Demonstrated a practical, accessible approach for laboratory VUV sources

Abstract

Many fields such as bio-spectroscopy and photochemistry often require sources of vacuum ultraviolet (VUV) pulses featuring a narrow linewidth and tunable over a wide frequency range. However, the majority of available VUV light sources do not simultaneously fulfill those two requirements, and few if any are truly compact, cost-effective and easy to use by non-specialists. Here we introduce a novel approach that goes a long way to meeting this challenge. It is based on hydrogen-filled hollow-core photonic crystal fiber pumped simultaneously by two spectrally distant pulses. Stimulated Raman scattering enables the generation of coherence waves of collective molecular motion in the gas, which together with careful dispersion engineering and control over the modal content of the pump light, facilitates cooperation between the two separate Raman combs, resulting in a spectrum that reaches deep into the VUV. Using this system, we demonstrate the generation of a dual Raman comb of narrowband lines extending down to 141 nm using only 100 mW of input power delivered by a commercial solid-state laser. The approach may enable access to tunable VUV light to any laboratory and therefore boost progress in many research areas across multiple disciplines.