The research area "Functional structures" contains projects, which are aiming for specific nonlinear functionalities:
In project C01 we aim to fabricate integrated frequency conversion devices tailored for spectral-temporal manipulation and detection of quantum light emitted from semiconductor structures. The frequency converters will be developed on LiNbO3 platform and we will target for high-performance plug-and-play devices with fiber pigtailed connectors. Incorporating conventional time-domain pulse characterization techniques such as streak cameras, unprecedented detection efficiency for sub-picosecond pulsed quantum light at the near-infrared spectrum shall be demonstrated.
The primary goal of project C02 is to develop the potential of LiNbO3 based integrated devices for new types of quantum metrology applications, such as quantum enhancement, super-sensitivity and dynamical sensors. Based on the capabilities of the LiNbO3-tool box components and experiences learned in the first phase of the project, we plan to explore the integrated non-linear SU(1,1) interferometers in different configurations which have a lot of advantages in comparison with conventional free-space interferometers. The goal of project C04 is the development of photonic devices with nonlinear functionalities that can be controlled by electric means. By ultrafast Stark effect tuning we want to obtain coherent electric control over the exciton and biexciton transitions in a quantum dot. We plan to use electrically contacted Bragg-microresonators to enhance the light-matter interaction.
The new project C05 targets the efficient manipulation of light beams with simultaneous frequency conversion at an ultrathin metal-ZnO metasurface. We plan to manipulate the amplitude and phase of the nonlinear waves based on the structural design and material composition on a nanoscale by utilizing a nonlinear Pancharatnam-Berry phase. By coupling the plasmonic resonances of the metal nanostructures to the virtual and real transitions in ZnO, we will enhance the nonlinearity of the combined system. With this concept, we will realize ultrathin nonlinear optical components, like nonlinear lenses and beamsplitters.
The new project C06 will investigate the theoretical potential and experimental feasibility of integrating superconducting nanowire single-photon detectors on lithium niobate waveguides, in order to implement a measurement-induced nonlinearity. Such nonlinearities arise from probabilistic measurement events and as such, can be implemented at very low light levels. By integrating such an operation, we can exploit the intrinsic phase stability and low-loss transmission of interferometric waveguide circuits, and theoretically explore the range of operations that phase-dependent measurement-induced nonlinearities can offer.