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arXiv · 2112.14907

Whispering-gallery modes promote enhanced optical backflow in a perforated dielectric microsphere

Yury E. Geints·Igor V. Minin·Oleg V. Minin
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Abstract

Optical energy flow inside a dielectric microsphere is usually codirected with the optical wavevector. At the same time, if the optical field in a microsphere is in resonance with one of the high-quality spatial eigenmodes (whispering-gallery modes - WGMs), a region of reverse energy flow emerges in the shadow hemisphere. This area is of considerable practical interest due to increased optical trapping potential. In this Letter, we consider a perforated microsphere with an air-filled single pinhole fabricated along the particle diameter and numerically analyze the peculiarities of WGM excitation in a nanostructured microsphere. A pinhole isolates the energy backflow region of a resonant mode and changes a perforated microsphere into an efficient optical tweezer. For the first time to our knowledge, we reveal the multiple enhancement of backflow intensity in the pinhole at a WGM resonance and discuss the way for its manipulation.

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Yury E. Geints, Igor V. Minin, Oleg V. Minin. 2021-12-30. Whispering-gallery modes promote enhanced optical backflow in a perforated dielectric microsphere. https://doi.org/10.1364/ol.452683

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