Tunable ultraviolet dispersive-wave emission driven directly by 40-fs Ti: sapphire laser pulses in hollow capillary fiber

TL;DR

This paper demonstrates a compact method to generate tunable ultraviolet dispersive waves using a hollow capillary fiber driven directly by 40-fs Ti:sapphire laser pulses, with wavelength tuning from 185 nm to 450 nm.

Contribution

It introduces a single-stage, gas-filled hollow capillary fiber setup for tunable UV dispersive wave generation directly driven by ultrafast laser pulses, with insights on suppressing pulse splitting.

Findings

UV DW wavelength tunable from 185 nm to 450 nm.

Raman-active gases suppress pulse splitting for longer wavelengths.

High-quality, smooth spectra achieved at longer wavelengths.

Abstract

We demonstrate that by using 1-m-long gas-filled hollow capillary fiber (HCF) with a core diameter of 100 {\mu}m, tunable ultraviolet (UV) dispersive-wave (DW) pulses can be generated in a compact, single-stage set-up driven directly by 40-fs Ti: sapphire laser pulses. By adjusting the gas type and pressure inside the HCF, the central wavelength of the UV DW can be continuously tuned from 185 nm to ~450 nm. In the experiment, we found that for longer-wavelength (from ~320 to ~450 nm) DW generation, Raman-active gas filled in the HCF can efficiently suppress the pulse splitting effect of the high-order soliton due to the Raman-induced pulse energy dissipation, leading to the high-quality DW generation at these wavelengths with smooth, single-peak spectra. These results provide some useful insights for designing compact, wavelength-tunable ultrafast UV light sources with microjoule-level pulse energies.