Heat and Temperature Localization via Fabry–Pérot Resonances at the Tip of a Nanofocusing Cone. Issue 18 (26th June 2022) - Cunha, Joao
Abstract: Nanofocusing of electromagnetic (EM) energy is an emblematic effect that guides EM energy along plasmonic conical structures, effectively focusing it at its nanometer‐sized extremity. However, EM energy nanofocusing could also be accompanied by (often disregarded) heating. Here, rigorous 3D finite element method simulations of a plasmonic conical structure were performed with a finite‐size apex excited by a continuous wave radially polarized beam over visible and near‐infrared wavelengths. Together with broadband nanofocusing the presence of narrowband Fabry–Pérot (FP) like resonances is demonstrated. Importantly, FP‐like resonances yield strong temperature localization that adds to the broadband nanofocusing component, providing an extra degree of freedom in tuning the temperature localization through proper selection of the structure dimensions suitable for applications in Raman, electron emission spectroscopies or sharp‐tip nanofabrication strategies. Abstract : Photo‐induced temperature effects are studied in a nanofocusing conical plasmonic structure with realistic dimensions. It is demonstrated that narrowband Fabry–Pérot like resonances yield strong temperature localization that adds to the broadband nanofocusing component, providing a strategy for tuning and enhancing the temperature localization at the apex of these structures.