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)