Nonphotochemical Laser-Induced Crystal Nucleation by an Evanescent Wave

Abstract

Crystal nucleation at a glass–solution interface has been demonstrated by evanescent-wave laser-induced nucleation for the first time. Nucleation was induced in supersaturated aqueous potassium chloride (KCl) solutions. The interaction volume was estimated to be <2 nL, localized within approximately 100 nm of the interface. Measurements of the power dependence of nucleation events showed a laser power threshold that was approximately 3 times higher than that in experiments in bulk solution; the average number of nucleation events above threshold was similar to that in bulk. Surfaces treated with a hydrophobic polydimethylsiloxane-based coating showed no nucleation over the coated regions. The localization offered by this method has significant potential benefit for studies of the nucleation mechanism or for patterning of crystal nuclei in two dimensions.