Areas of research
The laboratory is divided into four areas of research:
A) Optical systems for measuring complex flows
Flow metrology: Use of frequency-modulated laser beams for high-resolution velocity measurements.
Flow processes in nature and technology include a variety of exciting phenomena. The MST investigates and realizes flow measurement methods, which can open new windows for flow studies. Examples are new methods in microfluidics (3D particle image velocimetry), precise measurements of shear or boundary layer flows, the contactless, seeding-free measurements of injection processes, aeroacoustics and combustion techniques.
B) Adaptive computational endoscopic systems
Existing microendoscopic systems are limited in the minimal diameter and to 2D imaging. Novel lensless 3D endoscopes with diameters below 500 µm are being investigated, realized together with partners from industry and applied with research partners at MST for instance in Optogenetics and tumor diagnostics.
The systems are based on holography for self-calibration, adaptive optics, fs-Lasers, speckle correlation techniques and digital signal processing based on deep learning.
C) Ultrasound based methods for the investigation of multi-dimensional flows of opaque fluids.
In a variety of industrial applications flows of liquid metals or semiconductors play a central role. Magnetic fields are used to mix liquids in order to improve the crystal growth (magneto-hydrodynamics, MHD). Model experiments with low-melting metals are important for understanding the flow phenomena. The MST aims to realize novel 3D ultrasound measurement systems with up to 225 transducer elements. Compression and streaming of measurement data enables long experiment durations, fulfilling the requirements of MHD. Along with numerical simulation the crystal growth process of silicon is investigated, to improving the growth and the quality of solar cells.
Expertise of the ultrasound group:
- Big Data (computational ultrasonic imaging)
- Real-Time Systems / Wireless Communication
- Image and Signal Processing Technique
- FPGA (compression of a data stream of 1.2 GB/s by a factor of 10)
- 4D Visualization of Flows
- Condition Monitoring of Technical Processes
D) Adaptive laser systems for biomedicine.
Distortions during the propagation of light can degrade optical measurements dramatically or even completely prevent. Examples are fluctuating surfaces of multi-phase fluids or light scattering biological tissue. With the availability of modern adaptive optics, e.g. deformable mirrors, MEMS and liquid crystal modulators, it is possible to correct such distortions. The MST is exploring methods and control strategies, which allow measurements through distorting interfaces and in biological tissue with deep penetration.