GraSP_Graphene Oberflächen Plasmonen für steuerbare Resonator-Quantenelektrodynamik

• Antragsteller: Professor Dr. Carsten Rockstuhl
• Fachliche Zuordnung: Theoretische Physik der kondensierten Materie ; Experimentelle Physik der kondensierten Materie ; Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen
• Förderung: Förderung von 2017 bis 2022
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 378579271

• Erstellungsjahr: 2023

Zusammenfassung der Projektergebnisse

The GraSP project was a joint effort between the Karlsruhe Institute of Technology in Germany and the Nicolaus Copernicus University in Torun, Poland that aimed to investigate the potential of graphene-based plasmonic nanostructures to control and tailor light-matter interactions. The project had two main objectives: developing a suitable methodology for studying the optical properties of graphene-based nanostructures and exploring the physical properties of these systems with a focus on their optical properties. The research focused on understanding the interaction of graphene nanoantennas with quantum emitters and the effect of chemical doping and optical pumping on the emission properties of these systems. The project was divided into two work packages. The first focused on developing a theoretical methodology and computational tools to study hybrid systems consisting of graphene nanoantennas and adatoms. The methodology developed was based on a singleparticle density operator using a tight-binding framework, which allowed for the calculation of quantities such as the induced dipole moment and the absorption and scattering crosssections. In addition, the project also integrated expertise in theoretical and computational quantum chemistry to study selected samples using time-dependent density-functional theory. The second work package focused on exploring the physics of these hybrid systems. It included the study of the effect of the graphene nanoantennas on the emission properties of close-by quantum emitters, as well as the impact of the type of edges (zig-zag or armchair) and the doping level on the emerging properties of the graphene nanostructures. The project developed a methodology to classify resonances in nanostructures as singleparticle-like or plasmon-like. Single-particle-like modes are discrete electronic transitions that can be predicted using the non-interacting energy level diagram. Plasmon-like modes emerge due to long-range electron-electron interaction and can deviate from predicted transition energies by the non-interacting energy landscape. The energy-based plasmonicity index developed in this project constitutes an alternative measure for what a plasmon is compared to previously introduced measures, e.g., the generalized plasmonicity index. While the generalized plasmonicity index is based on the induced potential that builds up in the structure in response to an unequal charge distribution and in real space, the energy-based plasmonicity index relies on the time-dynamics of electronic population in energy space. If the contributing states exchange electronic population monotonously in time, we speak of a single-particle-like mode. If population is exchanged in an oscillatory manner, we speak of a "plasmon-like" resonance. The interaction of an adatom with a graphene antenna can lead to the hybridization of their orbitals and the modification of transition energies and transition dipole moment elements. This can impact the spontaneous emission rate, which can be enhanced or quenched at short distances due to the tunneling effect. Rabi oscillations, which measure the coupling strength between the adatom and the graphene antenna, generally decrease as the coupling strength increases. This is due to the relatively large dipole moment of the isolated adatom compared to the small dipole moments of transitions between states of the isolated graphene antenna. As the adatom hybridizes with the antenna, the HOMO and LUMO states extend over the antenna and the transition dipole moment decreases, leading to a decrease in the Rabi frequency.

Projektbezogene Publikationen (Auswahl)

• Enhancement of and interference among higher order multipole transitions in molecules near a plasmonic nanoantenna. Nature Communications, 10(1).
  Rusak, Evgenia; Straubel, Jakob; Gładysz, Piotr; Göddel, Mirko; Kędziorski, Andrzej; Kühn, Michael; Weigend, Florian; Rockstuhl, Carsten & Słowik, Karolina
  
• Energy-Based Plasmonicity Index to Characterize Optical Resonances in Nanostructures. The Journal of Physical Chemistry C, 124(44), 24331-24343.
  Müller, Marvin M.; Kosik, Miriam; Pelc, Marta; Bryant, Garnett W.; Ayuela, Andrés; Rockstuhl, Carsten & Słowik, Karolina
  
• Interaction of atomic systems with quantum vacuum beyond electric dipole approximation. Scientific Reports, 10(1).
  Kosik, Miriam; Burlayenko, Oleksandr; Rockstuhl, Carsten; Fernandez-Corbaton, Ivan & Słowik, Karolina
  
• From single-particle-like to interaction-mediated plasmonic resonances in graphene nanoantennas. Journal of Applied Physics, 129(9).
  Müller, Marvin M.; Kosik, Miriam; Pelc, Marta; Bryant, Garnett W.; Ayuela, Andrés; Rockstuhl, Carsten & Słowik, Karolina
  
• Modification of the optical properties of molecular chains upon coupling to adatoms. Physical Review B, 104(23).
  Müller, Marvin M.; Kosik, Miriam; Pelc, Marta; Bryant, Garnett W.; Ayuela, Andrés; Rockstuhl, Carsten & Słowik, Karolina
  
• Modeling and measuring plasmonic excitations in hollow spherical gold nanoparticles. The Journal of Chemical Physics, 156(9).
  Müller, Marvin M.; Perdana, Nanda; Rockstuhl, Carsten & Holzer, Christof
  
• Revising quantum optical phenomena in adatoms coupled to graphene nanoantennas. Nanophotonics, 11(14), 3281-3298.
  Kosik, Miriam; Müller, Marvin M.; Słowik, Karolina; Bryant, Garnett; Ayuela, Andrés; Rockstuhl, Carsten & Pelc, Marta