Theoretical analysis of polymeric and crystalline thick films melting with a single gold nanoparticle embedded in a transparent matrix under nanosecond pulsed laser excitation

Optothermal properties of noble metal nanoparticles can be used in a wide range of applications. This paper presents the results of a theoretical study on the utilization of laser-induced heating of a gold nanoparticle (GNP) to melt a region of a transparent material with sub-wavelength spatial resolution. The considered system consists of a 10 or 15 nm diameter GNP fixed inside a silica substrate. The silica surface is covered with a thick film of the transparent polymeric or crystalline material. The heating and melting processes are studied under a 7.5 ns pulsed laser illumination. Calculations are conducted under three temperature limits, on the maximum temperature of the free electrons, the maximum temperature of the GNP and the maximum temperature of the film layer. The temperature limits lead to the limiting of the average laser power. The maximum allowable value of the average laser power and the effect of various parameters on spatial characteristics of the molten region are considered.