Laser ablation of solid substrates in a water-confined environment

Citation
S. Zhu et al., Laser ablation of solid substrates in a water-confined environment, APPL PHYS L, 79(9), 2001, pp. 1396-1398
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
APPLIED PHYSICS LETTERS
ISSN journal
0003-6951 → ACNP
Volume
79
Issue
9
Year of publication
2001
Pages
1396 - 1398
Database
ISI
SICI code
0003-6951(20010827)79:9<1396:LAOSSI>2.0.ZU;2-K
Abstract
Laser ablation of Si under a water surface has been investigated. The laser used is a KrF excimer laser, which has a wavelength of 248 nm and a pulse duration of 23 ns. It is found that the laser ablation rate of Si varies wi th the thickness of the water layer above the Si substrates. The laser abla tion rate is the most highly enhanced with a water layer of 1.1 mm. It is a ssumed that the plasma generated in the water confinement regime with an op timal water layer thickness induces the strongest pressure. This high-press ure, high-temperature plasma results in the highest ablation rate. A wide-b and microphone is used to detect the audible acoustic wave generated during the laser ablation. The amplitude of the acoustic wave is closely related to the ablation rate. It is found that the first peak-to-peak amplitude of the acoustic wave is the strongest when the water layer thickness is 1.1 mm above the substrate. Fast Fourier transform analysis of the wave forms sho ws that there are several frequency components included in the acoustic wav es. The dominant frequency component decreases from 10.6 to 3.5 kHz as the water layer thickness varies from 1 to 2.2 mm. Diagnostics of the acoustic wave emission can be used to find the optimal water layer thickness to enha nce the laser ablation rate. With proper calibration, acoustic-wave detecti on can be used as a real-time monitoring of the laser ablation. (C) 2001 Am erican Institute of Physics.