Fresnel polarisation of infra-red radiation by elemental bismuth

Bruno S C Alexandre,Jaime E Santos,Luís C Martins,Nuno M R Peres,António J Pontes

doi:10.1140/epjb/e2020-10090-9

Bruno S C Alexandre, Jaime E Santos + Show 3 more

Open Access

https://doi.org/10.1140/epjb/e2020-10090-9

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Abstract

We revisit the classical problem of electromagnetic wave refraction from a lossless dielectric to a lossy conductor, where both media are considered to be non-magnetic, linear, isotropic and homogeneous. We derive the Fresnel coefficients of the system and the Poynting vectors at the interface, in order to compute the reflectance and transmittance of the system. We use a particular parametrisation of the referred Fresnel coefficients so as to make a connection with the ones obtained for refraction by an interface between two lossless media. This analysis allows the discussion of an actual application, namely the Fresnel polarisation of infra-red radiation by elemental bismuth, based on the concept of pseudo Brewster's angle.

Highlights

Propagation of electromagnetic (EM) waves is a central problem in electromagnetism and optics
We studied the problem of light refraction at an interface separating a lossless dielectric from a lossy conductive medium
We explored the concept of pseudo Brewster’s angle, the angle for which the p-polarised component of reflectance has a minimum when radiation is impinging on the lossy medium

Summary

Introduction

Propagation of electromagnetic (EM) waves is a central problem in electromagnetism and optics. Considering the general case of a non-uniform wave and taking the angle between the vectors k2 and k2 to be given by ζ , if we substitute k2 in terms of k2 in (15) using (16), we obtain the dispersion equation for k2. Do note that if we were considering refraction by a slab of lossy material, the field in medium 2 would include a reflected component and the where we stress that αt and φt are real parameters, which have to be adequately chosen so as to enforce the transversality condition for Et (r), equation (3), given that the wave vector kt is complex. Substituting the known expressions for these fields as given by equations (21), (22) and (23), we obtain after averaging over a period of the incoming wave, for the Poynting vector in medium 1 [23].

Power relations at the interface

Fresnel Polarisation in Elemental Bismuth

Conclusions

A The Drude approximation

B Poynting’s vector in lossy media