In this action, novel opto-mechanical and purely mechanical nanostructures were designed and realized in order to shield QDs from some of the light (optical) and sound (mechanical) modes in their environment. However, before integrating QDs in the designed nanostructures it was of vital importance to control the electrical environment of the QDs. This was accomplished by the design of a diode consisting of an n-i-n-i-p heterostructure, which is compatible with the stringent thickness requirements of the various steps in the nano-fabrication procedure. After this sample was grown by collaborators in Bochum, detailed characterization was carried out showing, for the first time, narrow optical linewidths and spin pumping on charge-tunable QDs in such an ultrathin diode [1]. To test if these excellent QD-properties endure in nano-structured samples, a free-standing beam of gallium-arsenide (3 micrometer x 10 micrometer) was fabricated using optical lithography. After successfully confirming that the narrow linewidths and efficient optical spin pumping could be observed in this structured sample, collaborators in Copenhagen fabricated more advanced photonic nano-structures. A demonstration of spin-controlled photon switching in a nano-beam waveguide was achieved [2]. Following this first demonstration, the nano-structures designed specifically for this action were fabricated. Significant changes had to be made to the experimental setup in Basel to enable a detailed analysis of a QD’s interaction with a well-isolated mechanical mode (“resolved sideband regime”). These measurements are currently ongoing.
[1] M. C. Löbl et al., Physical Review B 96, 165440 (2017)
[2] A. Javadi et al., Nature Nanotechnology 13, 398–403 (2018)