Femtosecond pulse laser ablation of sapphire in ambient air

• Published in: Applied surface science Vol. 228; no. 1; pp. 221 - 226
• Main Authors: Wang, X.C., Lim, G.C., Zheng, H.Y., Ng, F.L., Liu, W., Chua, S.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.04.2004; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Damage threshold; Exact sciences and technology; Femtosecond pulse laser ablation; Incubation effect; Physics; Sapphire; Self-focusing; Damage threshold; Femtosecond pulse laser ablation; Self-focusing; 79.20.Ds; Sapphire; Incubation effect; Physical radiation effects; Micromachining; Etching; Film growth; 79.20.Ds Femtosecond pulse laser ablation; Laser radiation; Focusing; Laser ablation technique; Damage; Defect formation
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2004.01.009

Femtosecond pulse laser ablation (pulse duration 150 fs, wavelength 775 nm, repetition rate 250 Hz) of sapphire in the ambient air was investigated. The quality and morphology of laser ablated sapphire were evaluated. The surface ablation threshold was found to decrease significantly with increasing the pulse number applied to the surface until reaching an almost constant level due to an incubation effect which is attributed to laser-induced defect formation. It was also showed that sub-micrometer pit holes, whose dimension was smaller than 1 μm, were produced with single femtosecond pulse due to the self-focusing effect of air. Under appropriate laser conditions, femtosecond pulse laser etching of sapphire with high quality could be achieved. The results have important consequences for applications, such as laser micromachining, and fabrication of sapphire-related devices.