Raman spectroscopic characterization of femtosecond Laser ablation of Silicon in air and liquid medium

Laser ablation of materials is mostly conducted in ambient air leading to high precision localized morphological and structural changes along with some redeposition of debris on the surface. While material ablation in a liquid medium can reduce thermal damage and debris, the fluid properties can influence morphological and structural changes. In this article, using Raman spectroscopy, we study structural changes induced by a single femtosecond laser pulse in silicon (100) immersed in water, isopropanol and glycerin and compare with air for a Gaussian and vortex beam carrying orbital angular momentum. We show that the extent of recrystallization after laser interaction is higher in air. In liquids, the laser modified regions exhibited greater percentage of poly-crystalline and amorphous phases. • Amorphous and polycrystalline phases in ablated silicon is more in liquids than air • Recrystallization of laser irradiated silicon is higher in air. • Phase change in isopropanol is lower compared to water and glycerin. • Vortex pulse causes more phase change in silicon in water than Gaussian pulse.