Electromagnetic energy and negative asymmetry parameters in coated magneto-optical cylinders: applications to tunable light transport in disordered systems
| Autor: | Alexandre Souto Martinez, Felipe A. Pinheiro, Tiago J. Arruda |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
DISPERSÃO DA LUZ Condensed matter physics Scattering Terahertz radiation Mean free path FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Electromagnetic radiation Light scattering Magnetic field 010309 optics 0103 physical sciences 0210 nano-technology Anisotropy Absorption (electromagnetic radiation) Physics - Optics Optics (physics.optics) |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | We investigate electromagnetic scattering of normally irradiated gyrotropic, magneto-optical core-shell cylinders using Lorenz-Mie theory. A general expression for time-averaged electromagnetic energy inside a coated gyroelectric and gyromagnetic scatterer is derived. Using realistic material parameters for a silica core and InSb shell, we calculate the stored electromagnetic energy and the scattering anisotropy. We show that the application of an external magnetic field along the cylinder axis induces a drastic decrease in electromagnetic absorption in a frequency range in the terahertz, where absorption is maximal in the absence of the magnetic field. We demonstrate not only that the scattering anisotropy can be externally tuned by applying a magnetic field, but also that it reaches negative values in the terahertz range even in the dipolar regime. We also show that this preferential backscattering response results in an anomalous regime of multiple light scattering from a collection of magneto-optical core-shell cylinders, in which the extinction mean free path is longer than the transport mean free path. By additionally calculating the energy-transport velocity and diffusion coefficient, we demonstrate an unprecedented degree of external control of multiple light scattering, which can be achieved by either applying an external magnetic field or varying the temperature. |
| Databáze: | OpenAIRE |
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