Universal Theory of Light Scattering of Randomly Oriented Particles: A Fluctuational-Electrodynamics Approach for Light Transport Modeling in Disordered Nanostructures

Abstract

Disordered nanostructures are commonly encountered in many nanophotonic systems, from colloid dispersions for sensing to heterostructured photocatalysts. Randomness, however, imposes severe challenges for nanophotonics modeling, often constrained by the irregular geometry of the scatterers involved or the stochastic nature of the problem itself. In this Article, we resolve this conundrum by presenting a universal theory of averaged light scattering of randomly oriented objects. Specifically, we derive expansion-basis-independent formulas of the orientation-and-polarization-averaged absorption cross section, scattering cross section, and asymmetry parameter, for single or a collection of objects of arbitrary shape. These three parameters can be directly integrated into traditional unpolarized radiative energy transfer modeling, enabling a practical tool to predict multiple scattering and light transport in disordered nanostructured materials. Notably, the formulas of average light scattering can be derived under the principles of fluctuational electrodynamics, allowing the analogous mathematical treatment to the methods used in thermal radiation, nonequilibrium electromagnetic forces, and other associated phenomena. The proposed modeling framework is validated against optical measurements of polymer composite films with metal-oxide microcrystals. Our work may contribute to a better understanding of light–matter interactions in disordered systems, such as plasmonics for sensing and photothermal therapy, photocatalysts for water splitting and CO 2 dissociation, photonic glasses for artificial structural colors, and diffuse reflectors for radiative cooling, to name just a few.

High-Efficiency, Mass-Producible, and Colored Solar Photovoltaics Enabled by Self-Assembled Photonic Glass

“…Here, we propose using a self-assembled photonic structure for colorizing PVs, consisting of dielectric microspheres with short-range correlations on the scale of visible wavelengths. Such photonic pigments have already been found in some living organisms, producing noniridescent structural colors that are visually pleasing. , Inspired by nature, recently some researchers have artificially made similar nanostructures by self-assembled colloidal microspheres, named photonic glass. − Because of the isotropic structure and purely dielectric building blocks, easily tunable and angle-independent colors could be generated, with no fading and low parasitic absorption of light. , In this case, we presume that photonic glass is a highly promising technology for developing colored PVs, and it is fully verified in this study.…”

Radiative Cooling Coating by Using Porous PE with PDMS Nanoparticles

“…To guide development of the PolyCool coating, a Monte-Carlo simulation code, which is a numerical solution for the radiative transfer equation, has been developed to simulate its performance. With the measured pore size distribution, the reflectance and transmission of PolyCool film have been simulated [31], the comparison between simulated reflectance and transmission and the corresponding measured values is presented in figure 2 (e), a good agreement between simulation and measurement has been achived. Due to the broad band of pore size distribution, the porous PE coating has a high reflectance in the solar spectrum.…”