Publikationen

We report the design and optimized fabrication of deformed whispering gallery mode resonators in silica with solely ICP-RIE. This allows us to control the morphology of the resonators more freely and results in low surface roughness. The light was coupled into the resonator using a state of the art tapered fiber approach and we determined the Q-factor in the range of 10^5

Three-dimensional (3D) flexible surface enhanced Raman scattering (SERS) substrates of silver nanoparticles (Ag-NPs) decorated Germanium nanowhiskers (Ge-NWHKs) grafted on carbon fiber cloth (CFC) (denoted as Ag-NPsGe-NWHKs@CFC) are constructed via chemical vapor deposition growth of high-density Ge-NWHKs on CFC and then assembly of Ag-NPs on the Ge-NWHKs by galvanic displacement. Ordered 3D framework of Ge-NWHKs grafted flexible CFC impels the formation of large amounts of Ag-NPs with homogenous distribution via spontaneous reduction of Ag+ ions. Thus, the Ag-NPs@Ge-NWHKs@CFC SERS substrates present ultra-high sensitivity, good reproducibility, and high flexibility. This SERS sensor has achieved a detection limit of 1 pM for Rhodamine 6G and 0.1 nM for thiram respectively. The as-fabricated SERS substrates show promising potential for applications in rapid detection of trace organic pollutants in the aquatic environment.

We exploit an adaptive control technique, namely funnel control, to establish both initial and recursive feasibility in Model Predictive Control (MPC) for output-constrained nonlinear systems. Moreover, we show that the resulting feedback controller outperforms the funnel controller both w.r.t. the required sampling rate for a zero-order-hold implementation and required control action. We further propose a combination of funnel control and MPC, exploiting the performance guarantees of the model-free funnel controller during a learning phase and the advantages of the model-based MPC scheme thereafter.