Year: 2026
Type: preprint
Abstract: Thermal confinement is a key parameter in photothermal applications, as it determines the spatial extent of the region affected by the generated heat. In this work, we develop a numerical treatment to quantify thermal confinement in spherical plasmonic nanoparticles under excitation conditions ranging from ultrashort pulses to the continuous-wave regime. The model combines generalized optical heating with a finite-difference solution of the transient heat equation and explicitly accounts for finite interfacial thermal conductance. To characterize the spatial distribution of heat, we introduce a thermal confinement radius defined from the temporal temperature envelope in the surrounding medium. We demonstrate that pulse duration acts as a highly effective, tuneable parameter to govern thermal confinement. Notably, we quantitatively show that finite interfacial thermal conductance can induce deviations of up to 20% in the spatial confinement radius and over 60% in the transient thermal construct under ultrashort excitation. By comparing the characteristic dimensions of representative targeting ligands with the resulting thermal-confinement length scales, we show how pulse duration can be precisely tailored to control target heating. These results provide a unified framework for predicting nanoscale heat localization paving the way for the rational design of high precision thermoplasmonic applications.
Source: arXiv (Cornell University)
Institutions: Universidad de Cantabria, Imperial College London
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222502748