Demonstration of long-lived high power optical waveguides in air

TL;DR

This paper demonstrates the creation of long-lived, high-power optical waveguides in air using femtosecond filaments, enabling long-distance laser pulse guiding with high efficiency and potential robustness against thermal effects.

Contribution

It introduces a novel method to generate stable, millisecond-long thermal waveguides in air using femtosecond filaments, facilitating high-energy laser transmission over extended distances.

Findings

Achieved 90% throughput over 15 Rayleigh lengths for 110 mJ pulses

Waveguides demonstrated lifetime of several milliseconds

Guided high-energy pulses limited only by available laser energy

Abstract

We demonstrate that femtosecond filaments can set up an extended and robust thermal waveguide structure in air with a lifetime of several milliseconds, making possible the very long range guiding and distant projection of high energy laser pulses and high average power beams. As a proof of principle, we demonstrate guiding of 110 mJ, 7 ns, 532 nm pulses with 90% throughput over ~15 Rayleigh lengths in a 70 cm long air waveguide generated by the long timescale thermal relaxation of an array of femtosecond filaments. The guided pulse was limited only by our available laser energy. In general, these waveguides should be robust against the effects of thermal blooming of extremely high average power laser beams.