Few pulses femtosecond laser exposure for high efficiency 3D glass micromachining

TL;DR

This paper presents a novel femtosecond laser and chemical etching process for high-aspect-ratio 3D glass microstructures, optimizing laser parameters to improve efficiency, resolution, and environmental safety.

Contribution

It introduces an optimized laser and chemical process that achieves higher aspect ratios with lower energy doses, advancing 3D glass micromachining technology.

Findings

Optimal energy dose is an order of magnitude lower than previous methods.

Precursor laser-induced defects enhance etching selectivity.

Process efficiency and environmental safety are significantly improved.

Abstract

Advanced three-dimensional manufacturing techniques are triggering new paradigms in the way we design and produce sophisticated parts on demand. Yet, to fully unravel its potential, a few limitations have to be overcome, one of them being the realization of high-aspect-ratio structures of arbitrary shapes at sufficiently high resolution and scalability. Among the most promising advanced manufacturing methods that emerged recently is the use of optical non-linear absorption effects, and in particular, its implementation in 3D printing of glass based on femtosecond laser exposure combined with chemical etching. Here, we optimize both laser and chemical processes to achieve unprecedented aspect ratio levels. We further show how the formation of pre-cursor laser-induced defects in the glass matrix plays a key role in etching selectivity. In particular, we demonstrate that there is an optimal energy dose, an order of magnitude smaller than the currently used ones, yielding to higher process efficiency and lower processing time. This research, in addition to a conspicuous technological advancement, unravels key mechanisms in laser-matter interactions essential in chemically-based glass manufacturing and offers an environmentally-friendly pathway through the use of less-dangerous etchants, replacing the commonly used hydrofluoric acid.