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arXiv · 2512.16407

Topological reorganization of near-field energy flow governing scattering transitions in subwavelength rectangular grooves

J. Sumaya-Martinez·J. Mulia-Rodriguez
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Abstract

The scattering of electromagnetic waves by subwavelength rectangular grooves has been extensively studied, yet its physical interpretation has largely relied on field-intensity distributions. Here we demonstrate that the transition from concave to convex scattering profiles observed as the groove width approaches the wavelength is governed by a topological reorganization of the near-field energy flow. Using a rigorous modal formulation for TM-polarized fields, we analyze the complex electromagnetic field and the associated time-averaged Poynting vector. We show that reducing the groove width induces the creation, migration, and annihilation of Poynting-vector singularities, including vortices and saddle points, leading to a qualitative restructuring of electromagnetic energy transport. This topological transition redirects the local energy flux and manifests as a convex scattering profile in the far field. The results establish a direct link between near-field energy topology and far-field scattering, providing a unified physical interpretation of subwavelength groove scattering.

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J. Sumaya-Martinez, J. Mulia-Rodriguez. 2025-12-18. Topological reorganization of near-field energy flow governing scattering transitions in subwavelength rectangular grooves. https://arxiv.org/abs/2512.16407

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