Ultra-Short Pulse Lasers for Microfabrication: A Review

Abstract

Ultra-short pulse lasers, generating coherent light pulses with pulse durations in the picosecond and femtosecond range, are becoming popular in precision laser microfabrication. They are benefiting not only from well-predicted laser ablation with the suppressed heat-affected zone but also by opening new processing opportunities, especially in transparent materials, due to enhanced non-linear interaction with the material. In this review, the evolution of various kinds of mode-locked lasers from a scientific toy to a robust industrial tool is reviewed. The utilization benefits of high-average-power, high-pulse-repetition-rate ultra-short pulse laser are closely related to beam shaping and manipulation techniques. Fast beam scanning with galvanometric and polygon scanners as well as multi-beam parallel processing methods were developed. Some hot applications areas are briefly described. The efficient use of photons from ultra-short pulse lasers pushed the development of optimization methods in the ablation process. Efforts toward upscaling the process by increasing the average power of mode-locked lasers made feedback to laser developers, and burst regime became a necessity as well as high-speed beam scanning devices. Unique opportunities of ultra-short pulses are successfully exploited in machining transparent materials, with glass separation being the leading application.

Study on the mechanism of thrombus ablation in vitro by burst‐mode femtosecond laser

“…At the same average power, compared with the traditional mode, the ablation efficiency of the invar foil with the burst-mode femtosecond laser was improved by an order of magnitude. Similar conclusions in the ablation experiments on other materials, that is, silicon, stainless steel and copper [20][21][22], with different laser parameters were also achieved. In the ablation experiments of dentin, compared with traditional mode, burst-mode femtosecond laser had lower thermal effect [23] and the ablation efficiency was increased by 6 times with the same average power density [24].…”

Structuring of thin films by ultrashort laser pulses

“…While the literature on that topic is already mature and very exhaustive, we try to break this down to a few key aspects only. For additional details, the reader is referred to some books and review articles here [1,[6][7][8][9][10][11][12][13][14][15][16]].…”

Fusion Weighted Sequential Three-Way Decision: A Model Revaluation Method for Online Monitoring and Robust Control of Drilling Stage

“…At present, laser processing plays a key role in fields such as electronic devices, aeronautics, biomedical and micro/nano devices [15]. However, the axial transmission characteristics are consistent with gaussian-shape laser, resulting in a wide axial ablation range and different to control via feed like traditional machining.…”