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arXiv · 2008.10688

Dispersion of electromagnetic waves in linear, homogeneous, and isotropic media

Masud Mansuripur
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Abstract

An electromagnetic wave-packet propagating in a linear, homogeneous, and isotropic medium changes shape while its envelope travels with different velocities at different points in spacetime. In general, a wave-packet can be described as a superposition of plane-waves having different frequencies {\omega} and different propagation vectors k. While the angular spread of the k-vectors gives rise to diffractive effects, it is the frequency-dependence of the refractive index of the host medium that is commonly associated with optical dispersion. When the spectral distribution of the wave-packet is confined to a narrow band of frequencies, and also when the spread of the k-vectors is not too broad, it is possible, under certain circumstances, to obtain analytical expressions for the local and/or global trajectory of the packet's envelope as it evolves in time. This paper is an attempt at a systematic description of the underlying physical assumptions and mathematical arguments leading to certain well-known properties of narrowband electromagnetic wave-packets in the presence of diffractive as well as (temporally) dispersive effects.

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Masud Mansuripur. 2020-08-24. Dispersion of electromagnetic waves in linear, homogeneous, and isotropic media. https://doi.org/10.1117/12.2567846

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