GraSP_Graphene Surface Plasmons for Tunable Cavity Quantum Electrodynamics

• Applicant: Professor Dr. Carsten Rockstuhl
• Subject Area: Theoretical Condensed Matter Physics ; Experimental Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 378579271

The GraSP project aims at a comprehensive exploitation of the unprecedented potential of graphene-based plasmonic nanostructures to control and to tailor light-matter interactions. Graphene is a versatile, broadband, adjustable, and tunable plasmonic material. Its ability to focus electromagnetic fields into nanometric regions of space is well beyond that of noble metals. Graphene is characterized by heavily suppressed absorption losses for photon energies below a threshold corresponding to the Fermi energy. A suitable level of doping via electric gating or chemical means can also shift the Fermi energy on-demand. This results in a wide-range dynamic control of the optical properties of graphene by merely turning a knob. Combined with the plasmonic lifetimes reaching hundreds of optical cycles, this renders graphene-based plasmonic nanostructures coupled to atomic systems (molecules, quantum dots, etc.) perfect candidates to implement nanoscale cavity-quantum-electrodynamics systems that would be tunable in time. Coupling strengths, emission properties, spectral properties, nonlinear interactions in addition to a dynamic control of graphene optical response enables multiple applications for signal processing at the quantum level. The objectives of the project are twofold. At first, we wish to establish the theoretical and nume-rical framework to investigate the coupling of graphene nanostructures to adjacent atomic systems. This requires the development of technical means to study the optical response of graphene nanostructures and to study the coupling to atomic systems. At second, we wish to perform a comprehensive analysis of the potential of graphene nanostructures to control the dynamics and spectral properties of atomic systems. The previously developed methodology constitutes here a prerequisite to thoroughly understand the full range of possibilities to control light-matter interaction offered by graphene nanostructures. With such analysis we aim to lay down the ground for diverse applications, including new types of quantum logic gates, generation of multiphoton nonclassical states of light, or atomic systems addressing activated on demand. All these devices would be naturally integrated on miniaturized chips. Graphene would unlock their tunability, a property of crucial importance for applications discussed within GraSP, however hardly accessible with traditional metal plasmonics.The project will be executed in parallel at the Karlsruhe Institute of Technology (KIT) and at the University of Nicolaus Copernicus (NCU) in Torun. The two partners bring into this project complementary expertise. The group from C. Rockstuhl (KIT) concentrates on studying the plasmonic properties of graphene nanostructures. The group from K. Slowik (NCU) studies the quantum dynamics. To achieve the objectives is only possible in the present collaboration and requires mutual efforts.

• DFG Programme: Research Grants
• International Connection: Poland
• Partner Organisation: Narodowe Centrum Nauki (NCN)
• Cooperation Partner: Dr. Karolina Slowik