# The effect of plasma-core induced self-guiding on phase matching of high-order harmonic generation in gases

## TL;DR

This study numerically investigates plasma-core induced self-guiding in gases, revealing its dual role in limiting the HHG cut-off but enhancing phase matching for efficient high-harmonic generation.

## Contribution

It demonstrates how plasma-core induced self-guiding improves phase matching conditions, enabling broad-range harmonic build-up despite cut-off limitations.

## Key findings

- Self-guiding regulates laser intensity and enhances phase matching.
- Constructive harmonic build-up occurs over a broad photon-energy range.
- Self-guiding can optimize high-flux HHG sources.

## Abstract

In this work we numerically study a self-guiding process in which ionization plays a dominant role and analyze its effect on high-order harmonic generation (HHG) in gases. Although this type of self-guiding --- termed as plasma-core induced self-guiding in previous works --- limits the achievable cut-off by regulating the intensity of the laser beam, it provides favorable conditions for phase matching, which is indispensable for high-flux gas high-harmonic sources. To underline the role of self-guiding in efficient HHG, we investigate the time-dependent phase matching conditions in the guided beam and show how the spatio-temporally constant fundamental intensity contributes to the constructive build-up of the harmonic field in a broad photon-energy range up to the provided cut-off.