Focusing of in-plane hyperbolic polaritons in van der Waals crystals with tailored infrared nanoantennas.
Sci Adv
; 7(41): eabj0127, 2021 Oct 08.
Article
em En
| MEDLINE
| ID: mdl-34623915
ABSTRACT
Phonon polaritons (PhPs)light coupled to lattice vibrationswith in-plane hyperbolic dispersion exhibit ray-like propagation with large wave vectors and enhanced density of optical states along certain directions on a surface. As such, they have raised a surge of interest, promising unprecedented manipulation of infrared light at the nanoscale in a planar circuitry. Here, we demonstrate focusing of in-plane hyperbolic PhPs propagating along thin slabs of α-MoO3. To that end, we developed metallic nanoantennas of convex geometries for both efficient launching and focusing of the polaritons. The foci obtained exhibit enhanced near-field confinement and absorption compared to foci produced by in-plane isotropic PhPs. Foci sizes as small as λp/4.5 = λ0/50 were achieved (λp is the polariton wavelength and λ0 is the photon wavelength). Focusing of in-plane hyperbolic polaritons introduces a first and most basic building block developing planar polariton optics using in-plane anisotropic van der Waals materials.
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MEDLINE
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En
Ano de publicação:
2021
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Article