Light-to-heat conversion of optically trapped hot Brownian particles

TL;DR

This paper investigates the local heat generation of anisotropic hybrid nanoparticles under optical trapping, combining experimental measurements, analytical modeling, and numerical simulations to understand their photothermal behavior at the single-particle level.

Contribution

It introduces a comprehensive approach integrating experiments, analytical models, and numerical simulations to analyze heat generation in anisotropic hybrid nanostructures using hot Brownian motion theory.

Findings

Consistent temperature profiles around trapped nanoparticles were obtained.

Theoretical and numerical models agree with experimental measurements.

Extended discrete dipole approximation for inhomogeneous nanostructures was validated.

Abstract

Anisotropic hybrid nanostructures stand out as promising therapeutic agents in photothermal conversion-based treatments. Accordingly, understanding local heat generation mediated by light-to-heat conversion of absorbing multicomponent nanoparticles at the single particle level have both forthwith become a subject of broad and current interest. Nonetheless, evaluating reliable temperature profiles around a single trapped nanoparticle is challenging from all experimental, computational, and fundamental viewpoints. Committed to filling this gap, the heat generation of an anisotropic hybrid nanostructure is explored by means of two different experimental approaches from which the local temperature is measured in a direct or indirect way, all in the context of the hot Brownian motion theory. The results were compared with analytical results supported by the numerical computation of the wavelength-dependent absorption efficiencies in the discrete dipole approximation for scattering calculations, which has been here extended to inhomogeneous nanostructures. Overall, we provide a consistent and comprehensive view of the heat generation in optical traps of highly absorbing particles under the viewpoint of the hot Brownian motion theory.