Measurements of microjoule-level, few-femtosecond ultraviolet dispersive-wave pulses generated in gas-filled hollow capillary fibers

TL;DR

This paper demonstrates the generation and direct measurement of few-femtosecond, microjoule-level ultraviolet dispersive-wave pulses in gas-filled hollow capillary fibers, using chirped mirrors and a self-diffraction FROG setup, without vacuum chambers.

Contribution

It provides the first direct measurement of ultrashort UV dispersive-wave pulses in atmosphere, showing their potential for practical applications without vacuum requirements.

Findings

Achieved 9.6 fs pulses at 384 nm and 9.4 fs at 430 nm.

Pulse width and shape depend on pulse energy and fiber length.

Ultraviolet pulses are broadband, tunable, and suitable for various applications.

Abstract

High-energy ultraviolet pulse generation in gas-filled hollow capillary fibers (HCFs) through dispersive-wave-emission process, has attracted considerable attentions in recent several years due to its great application potentials in ultraviolet spectroscopy and photochemistry. While the ability of this technique to deliver high-energy, ultrafast ultraviolet pulses is widely recognized, few-fs duration of {\mu}J-level dispersive-wave (DW) pulses has, however, escaped direct measurements. In this letter, we demonstrate that using several chirped mirrors, few-fs ultraviolet DW pulses can be obtained in atmosphere environment without the use of vacuum chambers. The pulse temporal profiles, measured using a self-diffraction frequency-resolved optical gating set-up, exhibit full-width-half-maximum pulse widths of 9.6 fs at 384 nm and 9.4 fs at 430 nm, close to the Fourier-transform limits. Moreover, theoretical and experimental studies reveal the strong influences of driving pulse energy and HCF length on temporal width and shape of the measured DW pulses. The ultraviolet pulses obtained in atmosphere environment with {\mu}J-level pulse energy, few-fs pulse width and broadband wavelength tunability are ready to be used in many applications.