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arXiv · 2507.20760

Near-field focusing and amplification of tip-substrate radiative heat transfer

Milo Vescovo·Philippe Ben-Abdallah·Riccardo Messina
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Abstract

The spatially resolved near-field radiative heat transfer between a nanoscale probe and a substrate is studied in the fluctuational electrodynamics framework within the dipolar approximation. It is shown that the introduction of a thin polar film atop a non-dispersive substrate can lead to both an enhancement and a lateral focusing of the heat exchange. The influence of the probe--substrate separation, film thickness and substrate permittivity is analyzed, revealing that the effect originates from near-field interactions governed by the interplay between film-induced modifications of electromagnetic mode dispersion and the distance-dependent coupling strength. The results highlight a viable route toward the active control of local radiative heat transfer at the nanoscale.

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Milo Vescovo, Philippe Ben-Abdallah, Riccardo Messina. 2025-07-28. Near-field focusing and amplification of tip-substrate radiative heat transfer. https://doi.org/10.1103/njnd-12n5

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