Research group leader
Solid-State Quantum Emitters
In order to make use of the advantages the laws of quantum mechanics offer it is mandatory to achieve precise control over quantum states. Photons can be easily controlled, but their production (emission) in a defined state is more difficult. A variety of systems which are capable of controlled emission of photons exist, with single atoms being the most obvious one. For a future quantum optical network and other quantum optical applications solid-state emitters are an alternative, as they can be more easily integrated into photonic circuitry.
In our research on solid-state quantum emitters we focus on two aspects:
Caption: Defects in hexagonal boron nitride are investigated in a confocal microscope using a two-photon process (left) and a one-photon process (right) .
Caption: On-chip photonic element consisting of a quantum emitter, a resonator and a coupled waveguide which serves as beamsplitter .
Scanning Probe Microscopy
Scanning probe microscopy can be used to alter the position of nanoparticles in a so called nanomanipulation process. With this, nanoparticles can not only be moved with nanometer precision but also be picked up and placed at a different location.
Caption: (a-d) show the process of positioning a nanoparticle. (e) and (f) show diamond nanoparticles before and after manipulation, respectively. A similar process can be used to pick up particles.
Caption: Scanning Electron Micrograph of a diamond nanoparticle on a photonic crystal cavity .
Solid-state emitters can also be used as probes to acquire information on their electrodynamic environment.
Caption: Cross section of the lifetime of a nitrogen vacancy center that is scanned over a silver nanowire .
 Non-linear excitation of quantum emitters in hexagonal boron nitride multiplayers, AW Schell, TT Tran, H Takashima, S Takeuchi, I Aharonovich, APL Photonics 1 (9), 091302
 Three-dimensional quantum photonic elements based on single nitrogen vacancy-centres in laser-written microstructures, AW Schell, J Kaschke, J Fischer, R Henze, J Wolters, M Wegener, O Benson, Scientific reports 3, 1577
 A scanning probe-based pick-and-place procedure for assembly of integrated quantum optical hybrid devices, AW Schell, G Kewes, T Schröder, J Wolters, T Aichele, O Benson, Review of Scientific Instruments 82 (7), 073709
 Scanning single quantum emitter fluorescence lifetime imaging: quantitative analysis of the local density of photonic states, AW Schell, P Engel, JFM Werra, C Wolff, K Busch, O Benson, Nano letters 14 (5), 2623-2627