Novel ultrafast laser ablation by bibursts in the MHz and GHz pulse repetition rates

TL;DR

This paper presents an experimental study on ultrafast laser ablation of copper and steel using MHz, GHz, and biburst regimes, revealing efficiency advantages and providing extensive data for modeling laser-matter interactions.

Contribution

First detailed experimental comparison of burst, biburst, and single-pulse ablation efficiencies at MHz and GHz repetition rates for metals.

Findings

Achieved high ablation efficiency of 8.8 um³/μJ for copper drilling.

Demonstrated optimal processing regimes for different materials.

Collected extensive data to enhance understanding of laser-matter interactions.

Abstract

Here, to the best of our knowledge, for the first time we report the in-depth experimental study of high ultrafast laser ablation efficiency for processing of copper and steel with single-pulses, MHz-, GHz- and burst in the burst (biburst) regime. The comparison of burst, biburst, and single-pulse ablation efficiencies was performed for beam-size-optimised regimes, showing the real advantages and disadvantages of milling and drilling processing approaches. Highly-efficient ultrashort pulse laser processing was achieved for ~1 um optical wavelength: 8.8 um3/uJ for copper drilling, 5.6 um3/uJ for copper milling, and 6.9 um3/uJ for steel milling. We believe that the huge experimental data collected in this study will serve well for the better understanding of laser burst-matter interaction and theoretical modelling.