Real-Time Optical Measurements of Nanoparticle-Induced Melting and Resolidification Dynamics

The photothermally induced nanoscale dynamics of rapid melting and resolidification of a thin layer of molecular material surrounding a nanoparticle is examined in real time by an all-optical approach. The method employs pulsed periodic modulation of the medium's dielectric constant through absorption of a low-duty-cycle laser pulse train by a single nanoparticle that acts as a localized heating source. Interpretation of experimental data, including inference of a phase change and of the liquid/solid interface dynamics, is obtained by comparing experimental data with results from coupled optical-thermal numerical simulations. The combined experimental/computational workflow pre-sented in this proof-of-principle study will enable future explorations of material parameters at nanoscale, which are often different from their bulk values and in many cases difficult to infer from macroscopic measurements.

Automated summary

In this study, the photothermally induced nanoscale dynamics of rapid melting and resolidification of a thin layer of molecular material surrounding a nanoparticle were investigated using an all-optical approach. By modulating the medium's dielectric constant through absorption of a low-duty-cycle laser pulse train by a single nanoparticle, the experimental data were compared with results from coupled optical-thermal numerical simulations to infer a phase change and the liquid/solid interface dynamics. The experimental/computational workflow presented in this proof-of-principle study will facilitate future explorations of material parameters at nanoscale.