Quasi-waveguide amplifiers based on bulk laser gain media in Herriott-type multipass cells

TL;DR

This paper introduces a novel laser amplifier geometry using Herriott-type multipass cells with bulk gain media, enabling longer effective interaction lengths and potentially higher amplification through thermal load distribution.

Contribution

It proposes a new quasi-waveguide amplifier design with a Herriott cell, enhancing bulk laser gain media performance over traditional single-pass setups.

Findings

Proof-of-principle demonstrated with Ti:sapphire

Potential for higher amplification due to thermal load management

Confined propagation similar to waveguides in bulk media

Abstract

We present here a new geometry for laser amplifiers based on bulk gain media. The overlapped seed and pump beams are repetitively refocused into the gain medium with a Herriott-type multipass cell. Similar to a waveguide, this configuration allows for a confined propagation inside the gain medium over much longer lengths than in ordinary single pass bulk amplifiers. Inside the gain medium, the foci appear at separate locations. A proof-of-principle demonstration with Ti:sapphire indicates that this could lead to higher amplification due to a distribution of the thermal load.