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For adaptive optics we combine our expertise in micro actuators, optics, materials, and processes. We investigate principles and applications for adaptive optics in which we integrate a suitable reliable actuation principle a priori at the core of the working principle. Our portfolio ranges from aspherical lenses via freeform lenses and mirrors to apertures and gratings.

Processes for and applications of magnetic microsystems form our second focus and are pushed to a new dimension by our unique method for coil winding on-chip. We do not only develop a robust alternative to the ubiquitous electrostatics, but also e.g. efficient micro power transmission or highly sensitive MR sensors.

Going one step further we also research the actuation principles and processes on their own, for example piezo actuation and bio-materials.

Adaptive optics

Adaptive Lens

In the Laboratory for Microactuators, we approach adaptive optics from the point of view of the actuation, of course together with the optical performance and requirements. Our research portfolio addresses most optical elements, such as various types of tunable lenses, axicon mirrors and lenses, freeform optical elements, apertures, and gratings. For light sensitive high-resolution applications, pure micro  optics often do not provide sufficient aperture, so we focus more on the millimetre rather than the micrometre scale.
The materials that we use include elastomers such as silicones (PDMS) but also for example flexible glass membranes and fluids. To integrate the actuation intrinsically into our devices, we frequently use piezo ceramics as they tend to be fast and efficient.
We have developed extensive know-how to process these materials and integrate them into the fabrication. In particular, we frequently combine classical and rapid-prototyping MEMS and precision mechanics techniques, for example UV-laser structuring, micro-moulding but also dedicated process solutions. >> more

MEMS fabrication processes

Coil Array

In the Microactuators lab, we have developed know-how in various fabrication processes, which extend beyond classical MEMS fabrication techniques. We combine rapid-prototyping fabrication methods such as laser structuring and CNC-milling with classical MEMS processes and high-volume fabrication processes like wire-bonding or hot-embossing. On the one hand such “hybrid processes” are often necessitated by the multi-scale nature of the devices that we develop and on the other hand, they often simply allow a fast and energy-efficient fabrication.
For the characterization of our prototypes, we frequently use optical techniques. While we also use commercially available systems, i.e. white light interferometry and microscopes, we also use and continuously advance our own custom solution for optical 3D profilometry. Together with the rapid prototyping, this allows us fast design iterations and process optimization.  >> more

Magnetic microsystems

Micro Harvester

The major technological challenges in the field of magnetic microsystems are the processes and materials. The Laboratory for Microactuators runs a unique, fast flexible and reliable process to manufacture three dimensional solenoidal microcoils using an automatic wirebonder. We develop and provide coils for on-chip magnetic micro actuators, microtransformers and power handling, inductive sensors, micro nuclear magnetic resonance, micro energy harvesting, or magnetic levitation.
We further focus on the processing of magnetic materials. We investigate for example the structuring and performance of multilayered amorphous metal films as well as of magnetic polymers. They are applied to guide the magnetic flux and enhance the field for example to maximize the coupling of a transformer. >> more

Piezo actuators

In-plane polarized piezo

Piezo actuation is a core technology that we integrate in our adaptive optical elements, for example because of the short response time and low power consumption. This has evolved into research on the piezo actuation concepts themselves.
The focus here is not on the materials themselves but on how to structure and polarize them for optimized or custom-made electromechanical response in actuators and ultrasound transducers.
Working in particular with PZT ceramics, we can, for example, create piezo films with an adjustable ratio of the in-plane strain tensor or let them buckle in desired free-form displacement profiles. >> more


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