The off-shell electromagnetic T-matrix: momentum-dependent scattering from spherical inclusions with both dielectric and magnetic contrasts

Abstract

The momentum- and frequency-dependent T-matrix operator for the scattering of electromagnetic waves by a dielectric/conducting and para- or diamagnetic sphere is derived as a Mie-type series, and presented in a compact form emphasizing various symmetry properties, notably the unitarity identity. This result extends to magnetic properties one previously obtained for purely dielectric contrasts by other authors. Several situations useful to spatially-dispersive effective-medium approximations to one-body order are examined. Partial summation of the Mie series is achieved in the case of elastic scattering.

Notes

Notes

1. For this reason, slightly different normalizations, in the form of alternative functions Q _l (x) = ϕ _l (x)/(l + 1) and were used by us in 17.

2. This requires Taylor-expanding δϵ and δμ in powers of these quantities, too.