2018-06-04
Experimental observation of a polarization vortex at an optical bound state in the continuum
Publication
Publication
Nat. Photonics , Volume 12 p. 397- 401
Optical bound states in the continuum (BICs) are states supported by a photonic structure that are compatible with free-space radiation, yet become perfectly bound for one specific in-plane momentum and wavelength1,2. Recently, it was predicted that light radiated by such modes around the BIC momentum–frequency condition should display a vortex in its far-field polarization profile, making the BIC topologically protected3. Here, we study a one-dimensional grating supporting a transverse magnetic mode with a BIC near 700 nm wavelength, verifying the existence of the BIC using reflection measurements, which show a vanishing reflection feature. Using k-space polarimetry, we measure the full polarization state of reflection around the BIC, highlighting the presence of a topological vortex. We use an electromagnetic dipole model to explain the observed BIC through destructive interference between two radiation channels, characteristic of a Friedrich–Wintgen-type BIC4. Our findings shed light on the origin of BICs and verify their topological nature.
| Additional Metadata | |
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| The Netherlands Organisation for Scientific Research (NWO) | |
| Springer Nature | |
| doi.org/10.1038/s41566-018-0177-5 | |
| Nat. Photonics | |
| Organisation | Resonant Nanophotonics |
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Doeleman, H., Monticone, F., den Hollander, W., Alù, A., & Koenderink, F. (2018). Experimental observation of a polarization vortex at an optical bound state in the continuum. Nat. Photonics, 12, 397–401. doi:10.1038/s41566-018-0177-5 |
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