Σας προσκαλούμε σε Σεμινάριο με τίτλο “Interactions between Quantum emitters and 2D nanostructures supporting surface modes” με ομιλητή τον Dr. Vasilios D. Karanikolas την Τετάρτη 7/12/2016 και ώρα 10:00 στην αίθουσα Σεμιναρίων του Τμήματος Επιστήμης των Υλικών.
Abstract
The theoretical investigation of the spontaneous emission (SE) rate, of a single quantum emitter (QE), and the energy transfer (ET) rate, between a pair of QEs, in the presence of conducting and semiconducting nanostructures will be presented. The SE and ET rates are enhanced several orders of magnitude, compared with their free-space values, when surface modes (SM) are excited. The SM are hybrid modes of the electrons or excitons, provided by the material, and the electromagnetic field. Noble metal and gated graphene nanostructures support surface plasmon modes, while semiconductor nanostructures support surface exciton modes. In this talk we focus on nanostructures composed from 2D materials, graphene and MoS2.
Graphene is a 2-dimensional material that can support surface plasmon modes and has superior electronic and higher mechanical properties. It has lower material losses compared to the noble metals Au and Ag. An infinite graphene layer [1] and a graphene nanodisk [2] can facilitate large interaction distances between quantum emitters by exciting the surface plasmon modes. The infinite graphene layer supports propagating SP modes while the graphene nanodisk supports confined SP modes. The optical properties of graphene can be modified by changing its chemical potential. This property allows us to dynamically switch -on and -of the interaction between QEs by changing the value of the chemical potential.
MoS2 is a material which optical response in the visible part of the spectrum. The SE rate of a QE is strongly modified by planar multilayer MoS2nanostructures, especially when the exciton polariton modes are excited [3]. The TM and TE exciton polariton modes are identified and their contribution to the SE of a QE is analysed. The influence of the increasing number of MoS2 to the SE rate of the QE will be also discussed.
Commercial applications such as light-emitting devices, light-harvesting devices, Raman scattering and biosensors will benefit by understanding the interaction between QE and 2D material nanostructures.
[1] Vasilios D. Karanikolas, Cristian A. Marocico, and A. Louise Bradley, “Dynamical tuning of energy transfer efficiency on a graphene monolayer”, Phys. Rev. B, 91, 125422 (2015)
[2] Vasilios D. Karanikolas, Cristian A. Marocico, and A. Louise Bradley, “Tunable and long-range energy transfer efficiency through a graphene nanodisk”, Phys. Rev. B, 93, 035426 (2016)
[3] Vasilios D. Karanikolas, Cristian A. Marocico, Paul R. Eastham and A. Louise Bradley, “Near-field relaxation of a quantum emitter to 2D semiconductors: surface dissipation and exciton polaritons”, arXiv:1608.02747 (2016)
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