Stimulated Brillouin Amplification with Flying Focus

TL;DR

This paper demonstrates that using a flying focus in plasma-based stimulated Brillouin scattering can significantly enhance laser amplification efficiency at lower intensities, overcoming previous interaction length limitations.

Contribution

First experimental demonstration of SBS amplification driven by a flying focus in a plasma channel, enabling efficient amplification at reduced intensities.

Findings

Achieved 14.5% conversion efficiency.

Realized SBS amplification at intensities over two orders of magnitude lower.

Validated flying focus as a tool for extending plasma interaction lengths.

Abstract

Material damage thresholds pose a fundamental limit to chirped pulse amplification (CPA) in high-power laser systems. Plasma-based amplification via stimulated Brillouin scattering (SBS) offers a damage-free alternative, yet its effectiveness has been hindered by instabilities that constrain interaction length. In this study, we report the first experimental demonstration of SBS amplification driven by a flying focus in a 3-mm plasma channel. The flying focus is generated using chromatic aberration from spherical lenses, with its velocity precisely measured by an interferometric ionization method achieving 6.6 fs timing resolution. At a focus velocity near -c, SBS amplification is realized at pump and seed intensities more than two orders of magnitude lower than in conventional setups, yielding a conversion efficiency of 14.5%. These results validate flying focus as a powerful tool for extending interaction lengths and enabling efficient plasma-based laser amplification at reduced intensities.