Plasmonic tuning of dark-exciton radiation dynamics and far-field emission directionality in monolayer WSe<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41544158.
- Also identified by DOI 10.1126/sciadv.aea5781 and PMC identifier 12810645.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Manipulation of excitonic emission properties is important for numerous photonic applications. Of particular interest are developing easy-to-implement yet effective approaches for controlling the radiation dynamics and directionality of spin-forbidden dark excitons (X<sub>D</sub>) in two-dimensional semiconductors. Here, we investigate the spectral, temporal, and directional characteristics of room-temperature X<sub>D</sub> emission from a tungsten diselenide monolayer coupled to a dissipative plasmonic nanocavity. Under resonant plasmon-exciton coupling, the radiative decay rate of X<sub>D</sub> is accelerated by nearly four orders of magnitude, and correspondingly, the X<sub>D</sub> lifetime is shortened to a subnanosecond level, making it comparable to that of bright excitons. Fitting the measured lifetimes with a Purcell-formalism-based cavity quantum electrodynamics model allows estimating of the intrinsic room-temperature X<sub>D</sub> lifetime to be about 24 ± 2.3 microseconds. Furthermore, the measured radiation patterns of the dark excitons show that subtle variations in the nanocavity orientation can effectively tailor the X<sub>D</sub> emission directionality, important for quantum technologies and optoelectronics applications.