Electrical control of optical emitter relaxation pathways enabled by graphene

• Published in: Nature physics Vol. 11; no. 3; pp. 281 - 287
• Main Authors: Tielrooij, K. J., Orona, L., Ferrier, A., Badioli, M., Navickaite, G., Coop, S., Nanot, S., Kalinic, B., Cesca, T., Gaudreau, L., Ma, Q., Centeno, A., Pesquera, A., Zurutuza, A., de Riedmatten, H., Goldner, P., García de Abajo, F. J., Jarillo-Herrero, P., Koppens, F. H. L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2015; Nature Publishing Group
• Subjects: 132/122; 140/133; 639/624/400/1021; 639/766/1130/2799; 639/766/119/544; 639/925/918/1054; Active control; Atomic; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Emittance; Emitters (electron); Energy flow; Energy transfer; Erbium; Excitation; Graphene; Ions; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; Optics; Pathways; Photovoltaics; Physics; Quantum physics; Semiconductors; Theoretical
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys3204

Controlling the energy flow processes and the associated energy relaxation rates of a light emitter is of fundamental interest and has many applications in the fields of quantum optics, photovoltaics, photodetection, biosensing and light emission. Advanced dielectric, semiconductor and metallic systems have been developed to tailor the interaction between an emitter and its environment. However, active control of the energy flow from an emitter into optical, electronic or plasmonic excitations has remained challenging. Here, we demonstrate in situ electrical control of the relaxation pathways of excited erbium ions, which emit light at the technologically relevant telecommunication wavelength of 1.5 μm. By placing the erbium at a few nanometres distance from graphene, we modify the relaxation rate by more than a factor of three, and control whether the emitter decays into electron–hole pairs, emitted photons or graphene near-infrared plasmons, confined to <15 nm from the graphene sheet. These capabilities to dictate optical energy transfer processes through electrical control of the local density of optical states constitute a new paradigm for active (quantum) photonics and can be applied using any combination of light emitters and two-dimensional materials. The relaxation processes of light-emitting excited ions are tunable, but electrical control is challenging. It is now shown that graphene can be used to manipulate the optical emission and relaxation of erbium near-infrared emitters electrically.