The research area of biophotonics covers a wide range of applications from biology and medicine to the life-sciences. Due to the multitude of disciplines spanned, biophotonics is a very interdisciplinary research area requiring expertise and technologies from all participating fields. The Biophotonic Sensors Group is located at the Institute of Microstructure Technology (IMT) and is collaborating closely with the Institute of Photonics and Quantum Electronics (IPQ) in research on label-free biophotonic sensors for lab-on-a-chip applications.

This research involves development, fabrication, and testing of integrated polymeric and silicon-based microoptical systems for point-of-care diagnosis and environmental monitoring. For early-stage disease recognition and sensitive detection of contaminants, e.g., in drinking water the relevant pathogens or contaminants must be detected at low concentrations. To amplify the weak interaction of light and analyte resonant structures, for e. g. whispering-gallery mode resonators are utilized. Attachment of particles from the analyte to the cavity results in detuning of the cavity’s resonance frequency, which can be monitored with high precision. The devices are fabricated in the clean room facilities at IMT using state-of-the art semiconductor technologies. Specific detection of a target molecule is achieved by biochemical surface functionalization of the resonator surface with a selective binding layer. In close collaboration with researchers at Institute of Nanotechnology (INT), Institute of Applied Computer Science (IAI), and Institute of Applied Physics (APH) technologies like microcontact stamping and droplet spotting are developed to functionalize individual resonators with high spatial precision. The biosensing experiments are performed in close collaboration with experts at the Universitätsklinikum Freiburg.

The optical high-precision metrology has a resolution in the range of micrometres which is mainly applied in coordinate-measuring technology for industrial high-precision manufacturing. For this purpose both, conventional systems based on discrete components, as well as optical microchips are deployed. Nanophotonic integration of the single components makes the system robust against vibrations and temperature changes and is suitable for the production of compact distance measurement sensors in large quantities. In the research field of optical coherence tomography (OCT), IPQ develops and applies OCT-systems, offering volumetric measurements with microscopic resolution in three dimensions. Novel OCT-system designs are developed and applied for particle and material characterization. One focus is the realization of systems with advanced measurement modes offering highest sensitivities. Further developments are OCT systems in microchip format and specialized measurement probes for inline process control.