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arXiv · 1805.11177

Valley-Selective Response of Nanoantennas Coupled to 2D Transition Metal Dichalcogenides

Alex Krasnok·Andrea Alu
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Abstract

Monolayer (1L) transition metal dichalcogenides (TMDCs) are attractive materials for several optoelectronic applications because of their strong excitonic resonances and valley-selective response. Valley excitons in 1L-TMDCs are formed at opposite points of the Brillouin zone boundary, giving rise to a valley degree of freedom that can be treated as a pseudospin and may be used as a platform for information transport and processing. However, short valley depolarization times and relatively short exciton lifetimes at room temperature prevent using valley pseudospin in on-chip integrated valley devices. Recently it has been demonstrated how coupling these materials to optical nanoantennas and metasurfaces can overcome this obstacle. Here, we review the state-of-the-art advances in valley-selective directional emission and exciton sorting in 1L-TMDC mediated by nanostructures and nanoantennas. We briefly discuss the optical properties of 1L-TMDCs paying special attention to their photoluminescence/absorption spectra, dynamics of valley depolarization and valley Hall effect. Then, we review recent works on nanostructures for valley-selective directional emission from 1L-TMDCs.

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Alex Krasnok, Andrea Alu. 2018-05-28. Valley-Selective Response of Nanoantennas Coupled to 2D Transition Metal Dichalcogenides. https://arxiv.org/abs/1805.11177

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