Highly-stable, flexible delivery of microjoule-level ultrafast pulses in vacuumized anti-resonant hollow-core fibers for active synchronization

TL;DR

This paper demonstrates the stable, flexible delivery of microjoule-level ultrafast pulses using vacuumized anti-resonant hollow-core fibers, enabling high-precision pulse synchronization with minimal walk-off and active control.

Contribution

It introduces a novel method for delivering stable ultrafast pulses over long distances with active stabilization, improving pulse synchronization in laser and accelerator applications.

Findings

Transmitted pulses show excellent stability in power and spectrum.

Walk-off between pulse trains is less than 6 fs RMS over 90 minutes.

Active control reduces walk-off to approximately 2 fs RMS.

Abstract

We demonstrate the stable and flexible light delivery of multi-{\mu}J, sub-200-fs pulses over a ~10-m-long vacuumized anti-resonant hollow-core fiber (AR-HCF), which was successfully used for high-performance pulse synchronization. Compared with the pulse train launched into the AR-HCF, the transmitted pulse train out of the fiber exhibits excellent stabilities in pulse power and spectrum, with pointing stability largely improved. The walk-off between the fiber-delivery and the other free-space-propagation pulse trains, in an open loop, was measured to be <6 fs root-mean-square (RMS) over 90 minutes, corresponding to a relative optical-path variation of <2x10-7. This walk-off can be further suppressed to ~2 fs RMS simply using an active control loop, highlighting the great application potentials of this AR-HCF set-up in large-scale laser and accelerator facilities.