# Highly Efficient Deep UV Generation by Four-Wave Mixing in Gas-Filled Hollow Core Photonic Crystal Fiber

## TL;DR

This paper demonstrates a highly efficient method for generating deep-ultraviolet ultrashort pulses using four-wave mixing in gas-filled hollow-core photonic crystal fibers, achieving high conversion efficiency and broad spectral bandwidths.

## Contribution

It introduces an experimental scheme that significantly improves UV pulse generation efficiency and bandwidth using gas-filled photonic crystal fibers with ultrashort pulses.

## Key findings

- Pump-to-idler energy conversion efficiency up to 38%
- Generation of sub-15 fs ultraviolet pulses
- Potential for scaling to high powers and other spectral regions

## Abstract

We report on a highly-efficient experimental scheme for the generation of deep-ultraviolet ultrashort light pulses using four-wave mixing in gas-filled kagom\'e-style photonic crystal fiber. By pumping with ultrashort, few $\mu$J, pulses centered at 400 nm, we generate an idler pulse at 266 nm, and amplify a seeded signal at 800 nm. We achieve remarkably high pump-to-idler energy conversion efficiencies of up to 38%. Although the pump and seed pulse durations are ~100 fs, the generated ultraviolet spectral bandwidths support sub-15 fs pulses. These can be further extended to support few-cycle pulses. Four-wave mixing in gas-filled hollow-core fibres can be scaled to high average powers and different spectral regions such as the vacuum ultraviolet (100-200 nm).

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Source: https://tomesphere.com/paper/1907.10959