Materials processing with tightly focused femtosecond vortex laser beams

TL;DR

This paper demonstrates the first use of tightly focused femtosecond laser vortex beams for precise material modification, achieving high-quality, micron-sized ring structures on glass surfaces with controlled laser parameters.

Contribution

It introduces a novel method of using femtosecond vortex beams for material processing, including synthesis and focusing techniques for ablation.

Findings

Successful fabrication of micron-sized ring structures

Controlled groove thickness below 100 nm

Effective use of moderate and high NA optics

Abstract

This letter is the first demonstration of material modification using tightly focused femtosecond laser vortex beams. Double-charge femtosecond vortices were synthesized with the polarization-singularity beam converter described in Ref [1] and then focused using moderate and high numerical aperture optics (viz., NA = 0.45 and 0.9) to ablate fused silica and soda-lime glasses. By controlling the pulse energy we consistently machine high-quality micron-size ring-shaped structures with less than 100 nm uniform groove thickness.