Magnetic spin-orbit interaction directs Bloch surface waves
Abstract
We study the directional excitation of optical surface waves controlled by the magnetic field of light. We theoretically predict that a spinning magnetic dipole develops a tunable unidirectional coupling of light to TE-polarized Bloch surface waves (BSWs). Experimentally, we show that the helicity of light projected onto a subwavelength groove milled in the top layer of a 1D photonic crystal (PC) controls the power distribution between two TE-polarized BSWs excited on both sides of the groove. Such a phenomenon is shown to be mediated solely by the helicity of the magnetic field of light, thus revealing a magnetic spin-orbit interaction. Remarkably, this magnetic optical effect is clearly observed with a near-field coupler governed by an electric dipole moment: it is of the same order of magnitude as the electric optical effects involved in the coupling. The magnetic spin-orbit interaction opens new degrees of freedom in the manipulation of light and offers appealing novel opportunities in the development of integrated optical functionalities.
- Publication:
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arXiv e-prints
- Pub Date:
- October 2017
- DOI:
- 10.48550/arXiv.1710.03584
- arXiv:
- arXiv:1710.03584
- Bibcode:
- 2017arXiv171003584W
- Keywords:
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- Physics - Optics