Formation, Dissolution,
and Transfer Dynamics of a
Millimeter-Scale Thin Liquid Droplet in Glycine Solution by Laser
Trapping
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Abstract
The formation, dissolution, and transfer of a millimeter-scale
dense liquid droplet are demonstrated by focusing a CW near-infrared
laser beam into a thin film of glycine solution in heavy water. The
entire process is investigated by directly monitoring the temporal
change in the two-dimensional surface profile using a laser displacement
meter. Upon laser irradiation, the surface depression is initially
induced by laser heating, followed by the formation of the shallow
convex-shaped droplet around the focal spot, in which the droplet
is always in contact with the surrounding solution through the ultrathin
solution layer. After the laser is switched off, the dissolution occurs
through the recovery from the ultrathin layer toward the original
solution film. When the laser is set to the outside of the droplet,
the solution depression is similarly induced, and subsequently the
droplet starts moving toward the focal spot. These processes are summarized
and discussed in view of laser-induced effects of concentration increase
and temperature elevation