Active magneto-optical control of spontaneous emission in graphene

We investigate the spontaneous emission rate of a two-level quantum emitter near a graphene-coated substrate under the influence of an external magnetic field or strain induced pseudo-magnetic field. We demonstrate that the application of the magnetic field can substantially increase or decrease the decay rate. We show that a suppression as large as 99$\%$ in the Purcell factor is achieved even for moderate magnetic fields. The emitter's lifetime is a discontinuous function of $|{\bf B}|$, which is a direct consequence of the occurrence of discrete Landau levels in graphene. We demonstrate that, in the near-field regime, the magnetic field enables an unprecedented control of the decay pathways into which the photon/polariton can be emitted. Our findings strongly suggest that a magnetic field could act as an efficient agent for on-demand, active control of light-matter interactions in graphene at the quantum level.

We would like to thank D. A. R. Dalvit, E. C. Marino, F. Guinea, H. Ulbricht, and L. Sapienza for valuable comments. W.J.M.K-K., G.B., F.S.S.R., and C.F. acknowledge CNPq, CAPES, and FAPERJ for financial support. W.J.M.K.-K. acknowledges financial support from the LANL LDRD program. B.A. acknowledges financial support from Fundac¸˜ao para a Ciˆencia e a Tecnologia, Portugal, through Grant No. SFRH/BD/78987/2011. F.A.P. thanks the Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, for the hospitality, and CAPES for funding his visit (Grant No. BEX 1497/14-6). F.A.P. also acknowledges CNPq (Grant No. 303286/2013-0) for financial support. N.M.R.P. acknowledges financial support from the Graphene Flagship Project (Contract No. CNECT-ICT-604391).