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Updated: Aug 15, 2026

Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
Published on: July 26, 2016
Optical theorem for electromagnetic field scattering by dielectric structures and energy emission from the evanescent
Yu V Gulyaev1, Yu N Barabanenkov, M Yu Barabanenkov
1Institute of Radioengineering and Electronics, Russian Academy of Sciences, 125009 Moscow, Russia.
Abstract:
We present an optical theorem for evanescent (near field) electromagnetic wave scattering by a dielectric structure. The derivation is based on the formalism of angular spectrum wave amplitudes and block scattering matrix. The optical theorem shows that an energy flux is emitted in the direction of the evanescent wave decay upon scattering. The energy emission effect from an evanescent wave is illustrated in two examples of evanescent wave scattering, first, by the electrical dipole and, second, one-dimensional grating with line-like rulings. Within the latter example, we show that an emitted energy flux upon evanescent wave scattering can travel through a dielectric structure even if the structure has a forbidden gap in the transmission spectrum of incident propagating waves.
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