Orientation averaging of optical chirality near nanoparticles and aggregates

Artificial nanostructures enable fine control of electromagnetic fields at the nanoscale, a possibility that has recently been extended to interaction between polarised light and chiral matter. The theoretical description such interactions, its application design optimised structures for chiroptical spectroscopies, brings new challenges common set tools used in nano-optics. In particular, effects often depend crucially on relative orientation scatterer incident light, but many experiments are performed with randomly oriented scatterers, dispersed solution. We derive expressions orientation-averaged local degree optical chirality field presence nanoparticle aggregate. This is achieved using superposition $T$-matrix framework, ideally suited derivation efficient orientation-averaging formulas scattering problems. Our results applied few model examples illustrate several nonintuitive aspects distribution around nanostructures. will be significant interest study assemblies designed enhance where numerically computation averaged enables more comprehensive exploration possible