Improvement in the Removal Efficiency of the Ultraviolet Laser Ablation by an Additional Simultaneous Irradiation of a Weak Infrared Laser

TL;DR

This study demonstrates that simultaneous weak infrared laser irradiation significantly enhances the removal efficiency of ultraviolet laser ablation across various materials, potentially reducing photon costs in laser machining.

Contribution

It introduces a simple method of using weak infrared laser irradiation to markedly improve ultraviolet laser ablation efficiency, a novel approach not previously reported.

Findings

A 50% to 280% increase in removal efficiency was observed.

The infrared laser fluency was only about 1.6% of the ultraviolet laser.

Improved surface morphology was achieved in laser micromachining.

Abstract

Remarkable improvement in the removal efficiency of the ultraviolet laser (fourth harmonic wave of Nd:YAG laser) ablation was observed by irradiating a weak infrared laser (fundamental wave of Nd:YAG laser) simultaneously and additionally to various kinds of materials, such as copper, acrylic resin, alumina, silicon and amorphous carbon. The improvement ratio ranged from 50% to 280%, while the laser fluency of the infrared laser was as small as about 1.6% of that of the ultraviolet laser. Although, we have not succeed in explaining the reasons why this effect occurs, it will have the potentiality to decrease the photon cost in the wide range of ultraviolet laser machining, because the method and the phenomena are simple and clear. The improvement in the morphology was also observed, when it is applied to the laser lathe micromachining.