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Contribution of Evanescent Waves to the Far-Field: the Atomic Point of View

Published

Author(s)

A Rahmani, Garnett W. Bryant

Abstract

Evanescent modes of the electromagnetic field are seldom invoked in conventional far-field optics, as their contribution far from the source (say a few wavelengths) is negligible. Contradicting this fact, in recent theoretical works, based on a particular decomposition of the free-space Green tensor, it has been asserted that evanescent waves do indeed contribute to the far field where they appear as an additional {difference} 1/r component of the field. We provide an explicit demonstration that evanescent modes do not contribute to the power radiated to the far field by any dipolar source. First we derive an expression for the free-space field susceptibility in which contributions from evanescent and homogeneous modes are separated, and then we use linear response theory to compute the decay rate for an atomic dipole in vacuum.
Citation
Optics Letters
Volume
25
Issue
No. 7

Keywords

angular spectrum representation, dipole radiation, evanescent waves, radiative decay spontaneous emission

Citation

Rahmani, A. and Bryant, G. (2000), Contribution of Evanescent Waves to the Far-Field: the Atomic Point of View, Optics Letters (Accessed April 20, 2024)
Created April 1, 2000, Updated February 17, 2017