Study on magnetically controlled laser-induced plasma-assisted ablation sapphire

Abstract

Laser-induced plasma-assisted ablation (LIPAA) of transparent hard and brittle materials presents distinctive advantages but is challenged by uncontrollable plasma. This paper examines the effects of both transverse and longitudinal magnetic fields on the LIPAA etching process of sapphire. The results indicate that the application of a transverse magnetic field significantly restricts plasma movement, leading to a 21.8 % decrease in spatter range and a 10.3 % increase in etching depth. Conversely, the longitudinal magnetic field causes the plasma to diverge, resulting in a wider sputtering distribution, and a decline in etching depth by 32.5 %. To explain the above experimental phenomena, the influence of the magnetic fields on laser-induced plasma was analyzed both experimentally and theoretically. Lastly, the study explored the impact of a magnetic field on the wettability of sapphire microgroove arrays. The findings indicated that the transverse magnetic field had a minor effect on the contact angle of the sapphire microgroove arrays. In contrast, the longitudinal magnetic field markedly decreased the contact angle from 81° to 24°, resulting in a substantial enhancement in the hydrophilicity of the microgroove arrays.