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arXiv · 2603.23538

Magneto-optic perturbation theory for near-complete violation of Kirchhoff's law of thermal emission at low magnetic fields

Daniel Cui·Aaswath P. Raman
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Abstract

Magneto-optic photonic systems can violate Kirchhoff's law of thermal emission by breaking Lorentz reciprocity. We develop a dispersive perturbation theory yielding an analytical expression for magneto-optical resonance frequency shifts in plasmonic semiconductors under applied magnetic fields. This expression shows the shift is governed by the overlap of the mode's optical spin density with the magneto-optical material. We use this expression to design a III-V metasurface that achieves nonreciprocal emissivity contrast of 0.8 at only 0.1 T, and demonstrate that the theory can explain order-of magnitude differences in magnetic field sensitivity between different photonic structures.

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Daniel Cui, Aaswath P. Raman. 2026-03-12. Magneto-optic perturbation theory for near-complete violation of Kirchhoff's law of thermal emission at low magnetic fields. https://arxiv.org/abs/2603.23538

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