Single droplet formation and crystal growth in urea solution induced by laser trapping

摘要

A single dense liquid droplet of urea is formed by irradiating a focused continuous wave near-infrared laser beam to a glass/solution interface of a thin film of the unsaturated D_2O solution though its dynamic deformation. Conversely, in the supersaturated solution, neither droplet formation nor large solution deformation is observed. This can be explained on the basis of its high viscosity. In addition, crystal growth and dissolution are demonstrated by focusing the laser beam close to the crystal generated in the solution. All results are here discussed in view of local temperature elevation, mass transfer due to convection, and laser trapping of the clusters due to photon pressure, by comparing with experimental results for glycine.