Ultrafast Heat Transfer at the Nanoscale: Controlling Heat Anisotropy

Thermoplasmonics has benefited from increasing attention in recent years by exploiting the photothermal effects within plasmonic nanoparticles to generate nanoscale heat sources. Recently, it has been demonstrated that exciting gold nanoparticles with ultrashort light pulses could be used to achieve high-speed light management and nanoscale heat-sensitive chemical reaction control. In this work, we study non-uniform thermal energy transient distribution inside cross-shaped nanostructures with femtosecond transient spectroscopy coupled to a thermo-optical numerical model, free of fitting parameters. We show experimentally and numerically that the polarization of the excitation light can control the heat distribution in the nanostructures. We also demonstrate the necessity of considering nonthermal electron ballistic displacement in fast transient heat dynamics models.

Automated summary

Thermoplasmonics has gained increasing attention for generating nanoscale heat sources using photothermal effects in plasmonic nanoparticles. By exciting gold nanoparticles with ultrashort light pulses, high-speed light management and nanoscale heat-sensitive chemical reaction control can be achieved. This study investigates the non-uniform thermal energy distribution in cross-shaped nanostructures using femtosecond transient spectroscopy and a thermooptical numerical model. The results show that the polarization of the excitation light can control heat distribution in the nanostructures, and nonthermal electron ballistic displacement is crucial in fast transient heat dynamics models.