Flexible delivery of high-power picosecond laser in purely-single optical mode of anti-resonant hollow-core fiber for micromachining

TL;DR

This paper demonstrates the effective delivery of high-power picosecond laser pulses through anti-resonant hollow-core fiber for micromachining, emphasizing mode purity and system stability improvements.

Contribution

It introduces a fiber delivery system with optimized mode suppression and stability for high-power ultrafast laser micromachining applications.

Findings

AR-HCF with higher d/D ratio improves mode purity

Enhanced micromachining quality with AR-HCF delivery

Better pointing stability than free-space systems

Abstract

We present the flexible delivery of picosecond laser pulses with up to 20 W average power over a 3-m-long sample of anti-resonant hollow-core fiber (AR-HCF) for laser micromachining applications. Our experiments highlight the importance of optical mode purity of the AR-HCF for the manufacturing precision. We demonstrate that compared with an AR-HCF sample with a capillary to core (d/D) ratio of ~0.5, the AR-HCF with a d/D ratio of ~0.68 exhibits better capability of high-order-mode suppression, giving rise to improved micromachining quality. Moreover, the AR-HCF delivery system exhibits better pointing stability and set-up flexibility than the free-space beam delivery system. These results pave the way to practical applications of AR-HCF in developing advanced equipment for ultrafast laser micromachining.