Wavelength Dependence of IR Laser for Dual-laser Shattering of a Water Microdroplet

Abstract

For the single- and dual-laser shattering of water microdroplets, the wavelength dependence of an infrared (IR) laser was experimentally examined in the range 2.25–3.75 µm using ion current measurements coupled with time-resolved imaging. Compared to a single IR laser, simultaneous illumination by dual IR lasers effectively compresses the spatial distribution of small fragments around the absorption maximum for the OH-stretching vibration of liquid water (λ = 2.75–3.25 µm). The effect can be explained by the small penetration depth of the IR laser toward water microdroplets.