Document Type

Article

Publication Date

2025

Publication Title

Advanced Optical Materials

Abstract

Nonradiating optical anapoles are special configurations of charge-current distributions that do not radiate. It was theoretically predicted that, for microspheres, electric and magnetic dipolar coefficients can simultaneously vanish by engineering the incident light, leading to the excitation of nonradiating hybrid optical anapoles. In this work, the experimental detection of hybrid optical anapoles in dielectric microspheres (TiO2) is reported using dual detection optical spectroscopy, developed to enable sequential measurement of forward and backward scattering under tightly-focused Gaussian beam (TFGB) illumination. The results show that the excitation of TiO2 microspheres (diameter, d ≈1 µm) under TFGB illumination leads to the appearance of scattering minima in both the forward and backward directions within specific wavelength ranges. These scattering minima are found to be due to vanishing electric and magnetic dipolar coefficients associated with hybrid optical anapoles. The ability to confine electromagnetic fields associated with hybrid optical anapoles can give rise to several novel optical phenomena and applications.

Funding Source

This material is based upon work supported by the National Science Foundation (NSF), Division of Materials Research under Grant No. DMR-2208240 and DMR-2116612. G.M.-T., I.G.-V., and I.T. acknowledge support from CSIC Research Platform on Quantum Technologies PTI-001, from IKUR Strategy under the collaboration agreement between Ikerbasque Foundation and DIPC/MPC on behalf of the Department of Education of the Basque Government and from Project No. PID2022-143268NB-I00 of Ministerio de Ciencia, Innovación y Universidades. This article was published Open Access thanks to a transformative agreement between Milner Library and Wiley.

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

DOI

10.1002/adom.202501315

Comments

First published in Advanced Optical Materials (2025): https://doi.org/10.1002/adom.202501315

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