Thermalization via Heat Radiation of an Individual Object Thinner than the Thermal Wavelength

TL;DR

This paper investigates the thermalization process of a microscopic silica fiber with a diameter smaller than the thermal wavelength, using optical measurements and a theoretical model to understand heat radiation effects.

Contribution

It provides a first-principles analysis of thermalization for subwavelength objects considering shape and size effects on heat radiation.

Findings

Excellent agreement between experimental data and the volumetric heat radiation model.

Heat radiation effects are significant for objects smaller than the thermal wavelength.

The model accurately predicts temperature dynamics based on shape and size.

Abstract

Modeling and investigating the thermalization of microscopic objects with arbitrary shape from first principles is of fundamental interest and may lead to technical applications. Here, we study, over a large temperature range, the thermalization dynamics due to far-field heat radiation of an individual, deterministically produced silica fiber with a predetermined shape and a diameter smaller than the thermal wavelength. The temperature change of the subwavelength-diameter fiber is determined through a measurement of its optical path length in conjunction with an ab initio thermodynamic model of the fiber structure. Our results show excellent agreement with a theoretical model that considers heat radiation as a volumetric effect and takes the emitter shape and size relative to the emission wavelength into account.