Enhancing the yield of high-order harmonics with an array of gas jets

TL;DR

This paper demonstrates that using an array of gas jets can significantly enhance high-order harmonic generation by leveraging quasi-phase-matching effects, leading to increased harmonic yield in experimental setups.

Contribution

The study introduces a novel approach of using gas jet arrays to improve high-order harmonic yield through periodic density modulation and quasi-phase-matching.

Findings

Gas jet arrays increase harmonic yield compared to single jets.

Periodic modulation of gas density enhances coherent harmonic build-up.

Quasi-phase-matching partially counteracts dephasing effects.

Abstract

We report the experimental observation of an enhancement in the yield of high-order harmonics using an array of gas jets as the source medium. By comparing the experimental outcome for jet arrays of different spacings with the predicted harmonic intensity in the case of slit sources of equivalent lengths, we clearly show how the periodic modulation of the gas density can improve the harmonic yield. This behavior may attributed to a quasi-phase-matching effect which increases the length of coherent harmonic build-up during propagation by partially counteracting the dephasing induced by free electrons.