The work group sensor systems develops compact and integratable detection systems using novel components, such as spatial light modulator arrays and diffractive optical elements (DOEs). The focal point of our work includes spectral sensor technology and optical far-field microimaging for applications in biophotonics. Our vision is the combination of spectral sensor technology with sub-diffraction microimaging and subsequent implementation in integratable multi-chip systems.
The setup of a spectral sensor system consists of an entrance slit array, a diffractive optical element (e.g., a grating), and a two-dimensional CCD. This arrangement is called a double array spectrometer. Currently, more than 20 subsystems having different parameters can be integrated into a single setup. A novel approach of our work group is the use of a 2D grating in the form of a diffractive optical element which can combine dispersing and focusing properties. In this manner, spectral sensors can be designed to be even smaller, and system-specific performance limits can be reduced even further.
Lens-free microscopy with interferences in the far field is the subject of our microimaging research. One new step is the measurement and adjustment of partially coherent lighting with coherence properties in the µm range. This permits the limitation of image generation specifically to the desired object area. We use a new deconvolution method following the principle of the information spatially distributed across the interference image – similar to the spatially distributed storing of information inside the brain.The interference image is split into partial images or “tiles,” individually reconstructed, and subsequently put together again. This method achieves the highest optical resolution worldwide. It corresponds to an aperture of more than 0.62 while the numerical effort is reduced by several orders of magnitude.