Wavelength dependence of IR laser for dual-laser shattering of a water microdroplet

For the single- and dual-laser shattering of water microdroplets, the wavelength dependence of an infrared (IR) laser was experimentally examined in the range 2.253.75 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 OHstretching vibration of liquid water (λ=2.753.25 μm). The effect can be explained by the small penetration depth of the IR laser toward water microdroplets.