Scattering characteristics of relativistically moving concentrically layered spheres

TL;DR

This paper investigates how the scattering and extinction properties of layered spheres change with relativistic velocity, highlighting the influence of Doppler shifts on resonance interactions in nanospheres and interstellar dust analogs.

Contribution

It introduces a detailed analysis of velocity-dependent scattering characteristics of layered spheres, emphasizing Doppler shift effects on resonance-based extinction cross sections.

Findings

Extinction cross section peaks near resonance wavelengths when Doppler shift aligns spectral content.

Velocity significantly alters scattering behavior in nanospheres and interstellar dust models.

Resonance effects are strongly dependent on the sphere's velocity and spectral content shifts.

Abstract

The energy extinction cross section of a concentrically layered sphere varies with velocity as the Doppler shift moves the spectral content of the incident signal in the sphere's co-moving inertial reference frame toward or away from resonances of the sphere. Computations for hollow gold nanospheres show that the energy extinction cross section is high when the Doppler shift moves the incident signal's spectral content in the co-moving frame near the wavelength of the sphere's localized surface plasmon resonance. The energy extinction cross section of a three-layer sphere consisting of an olivine-silicate core surrounded by a porous and a magnetite layer, which is used to explain extinction caused by interstellar dust, also depends strongly on velocity. For this sphere, computations show that the energy extinction cross section is high when the Doppler shift moves the spectral content of the incident signal near either of olivine-silicate's two localized surface phonon resonances at 9.7 $\mu$m and 18 $\mu$m.