Programmable hyperbolic polaritons in van der Waals semiconductors.
Science
; 371(6529): 617-620, 2021 02 05.
Article
in En
| MEDLINE
| ID: mdl-33542134
ABSTRACT
Collective electronic modes or lattice vibrations usually prohibit propagation of electromagnetic radiation through the bulk of common materials over a frequency range associated with these oscillations. However, this textbook tenet does not necessarily apply to layered crystals. Highly anisotropic materials often display nonintuitive optical properties and can permit propagation of subdiffractional waveguide modes, with hyperbolic dispersion, throughout their bulk. Here, we report on the observation of optically induced electronic hyperbolicity in the layered transition metal dichalcogenide tungsten diselenide (WSe2). We used photoexcitation to inject electron-hole pairs in WSe2 and then visualized, by transient nanoimaging, the hyperbolic rays that traveled along conical trajectories inside of the crystal. We establish here the signatures of programmable hyperbolic electrodynamics and assess the role of quantum transitions of excitons within the Rydberg series in the observed polaritonic response.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Science
Year:
2021
Document type:
Article
Affiliation country:
United States