Generation of broadband circularly polarized deep-ultraviolet pulses in hollow capillary fibers

TL;DR

This paper presents a new method for generating broadband, high-energy, circularly polarized deep-ultraviolet femtosecond pulses using hollow capillary fibers, with potential applications in various spectral regions.

Contribution

It introduces an efficient seeded four-wave mixing technique in gas-filled hollow fibers for producing circularly polarized deep-UV pulses with high energy and broad spectra.

Findings

Generated idler pulses at 266 nm with >25 μJ energy

Achieved over 95% ellipticity in the generated pulses

Spectral bandwidth of 27 nm for the idler pulses

Abstract

We demonstrate an efficient scheme for the generation of broadband, high-energy, circularly polarized femtosecond laser pulses in the deep ultraviolet through seeded degenerate four-wave mixing in stretched gas-filled hollow capillary fibers. Pumping and seeding with circularly polarized 35 fs pulses centered at 400 nm and 800 nm, respectively, we generate idler pulses centered at 266 nm with more than 25 microjoule of energy and over 95% spectrally averaged ellipticity. Even higher idler energies and broad spectra (27 nm bandwidth) can be obtained at the cost of reduced ellipticity. Our system can be scaled in average power and used in different spectral regions, including the vacuum ultraviolet.