Processing of a human fingernail surface by a tightly focused femtosecond laser pulse is investigated. The processed structure in the fingernail surface is strongly dependent on focus position and irradiation energy of a laser pulse. A variety of structures depending on the focus position were observed. A sudden change in the size of the processed structure according to the irradiation pulse energy is also observed. From a linear theoretical estimation based on the diffraction of a laser beam, we found that the sudden change is mainly due to the diffraction pattern generated by the circular aperture of an objective lens. The processing feature is investigated by comparing the structures processed in a fingernail with those processed in glass.

Date Published: 8 October 2004
PDF: 6 pages
Proc. SPIE 5662, Fifth International Symposium on Laser Precision Microfabrication, (8 October 2004); doi: 10.1117/12.596598

Published in SPIE Proceedings Vol. 5662:
Fifth International Symposium on Laser Precision Microfabrication
Isamu Miyamoto; Henry Helvajian; Kazuyoshi Itoh; Kojiro F. Kobayashi; Andreas Ostendorf; Koji Sugioka, Editor(s)