Format

Send to

Choose Destination
Nat Nanotechnol. 2018 Jan;13(1):59-64. doi: 10.1038/s41565-017-0003-0. Epub 2017 Nov 20.

Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect.

Park KD1,2,3,4, Jiang T1,2,3,4, Clark G5,6, Xu X5,6, Raschke MB7,8,9,10.

Author information

1
Department of Physics, University of Colorado, Boulder, CO, USA.
2
Department of Chemistry, University of Colorado, Boulder, CO, USA.
3
JILA, University of Colorado, Boulder, CO, USA.
4
Center for Experiments on Quantum Materials, University of Colorado, Boulder, CO, USA.
5
Department of Physics, University of Washington, Seattle, WA, USA.
6
Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
7
Department of Physics, University of Colorado, Boulder, CO, USA. markus.raschke@colorado.edu.
8
Department of Chemistry, University of Colorado, Boulder, CO, USA. markus.raschke@colorado.edu.
9
JILA, University of Colorado, Boulder, CO, USA. markus.raschke@colorado.edu.
10
Center for Experiments on Quantum Materials, University of Colorado, Boulder, CO, USA. markus.raschke@colorado.edu.

Abstract

Excitons, Coulomb-bound electron-hole pairs, are elementary photo-excitations in semiconductors that can couple to light through radiative relaxation. In contrast, dark excitons (XD) show anti-parallel spin configuration with generally forbidden radiative emission. Because of their long lifetimes, these dark excitons are appealing candidates for quantum computing and optoelectronics. However, optical read-out and control of XD states has remained challenging due to their decoupling from light. Here, we present a tip-enhanced nano-optical approach to induce, switch and programmably modulate the XD emission at room temperature. Using a monolayer transition metal dichalcogenide (TMD) WSe2 on a gold substrate, we demonstrate ~6 × 105-fold enhancement in dark exciton photoluminescence quantum yield achieved through coupling of the antenna-tip to the dark exciton out-of-plane optical dipole moment, with a large Purcell factor of ≥2 × 103 of the tip-sample nano-cavity. Our approach provides a facile way to harness excitonic properties in low-dimensional semiconductors offering new strategies for quantum optoelectronics.

PMID:
29158602
DOI:
10.1038/s41565-017-0003-0

Supplemental Content

Loading ...
Support Center