Measurement of Laser-Induced Mass Removal Using Shock Wave Imaging

Hendijanifard, M., Willis, D.A., “Measurement of Laser-Induced Mass Removal Using Shock Wave Imaging”, Proceedings of the ALAC, 2009 (Presented at Advanced Laser Applications Conference, September, 2009).

Hendijanifard ALAC2009.pdf
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Abstract
This paper explains an experimental technique for estimating the amount of material removed during laser ablation. The
technique uses transient measurements of the laser-induced blast wave and an energy balance model to determine the quantity of mass
removed. Aluminum films of 200 nm thickness deposited on glass substrate are used for this investigation. The experimental setup
consists of an Nd:YAG laser with 1064 nm wavelength and 7 ns pulse duration (FWHM) which is synchronized with a short pulse
illumination laser used for shadowgraph imaging to measure shock positions. A N2 laser pumped dye laser at 500 nm wavelength with
a 3 ns pulse duration (FWHM) is used for shadowgraph illumination, allowing nanosecond time resolution. Shock wave positions as a
function of time are curve-fit to the Taylor-Sedov spherical blast wave solution to determine blast energy. Using an energy balance
model to estimate the amount of vaporized material, it is shown that the mass removal is accurately predicted for laser fluences greater
than 6.5J/cm2.