How do mechanical vibrations interact with electromechanical vibrations? This is the question that Professor Silvan Schmid has been working on for several years. At the Institute of Sensor and Actuator Systems (Faculty of Electrical Engineering and Information Technology), he and his team are working on microscopically small sensors in which the subtle interaction between quite different types of vibration is utilised.
In 2016, he was awarded the ERC Starting Grant by the European Research Council (ERC). The results that emerged from this ERC project were so promising that he has now managed to secure additional funding through the Proof of Concept (PoC) Grant, which has a value of 150,000 euros. Silvan Scmid will use the grant to produce a fully functional prototype for an innovative, highly sensitive infrared sensor within 18 months.
Using vibrations to measure infrared radiation
"Infrared detectors are indispensable in many specialist fields," says Silvan Schmid. "They are needed in chemical analysis, environmental analysis, quality control in the pharmaceutical industry and even for basic astronomical research." However, it is difficult to produce highly sensitive sensors that react to infrared waves. Standard photodiodes, such as those used for digital cameras, do not work well enough in the infrared spectrum.
However, research at TU Wien is pursuing a very different concept - nanomechanics: a minute membrane, with a thickness of just a few nanometres, is overlaid with a thin layer that absorbs infrared radiation particularly well. If only infrared light hits this membrane, it heats it up and thus changes its vibration frequency - similar to how the sound of a drum changes very slightly when you heat up the drum skin.
"By measuring this mechanical vibration behaviour electronically, we can ascertain whether the membrane has been lit with infrared rays - with unprecedented sensitivity," says Silvan Schmid. Previous detectors also had to be cooled to very low temperatures - it should be possible to use the new sensor at room temperature, without any cooling.
Key pilot tests have already been successful. "We now know that the concept works," explains Silvan Schmid. "We now have to develop a functioning prototype that we can also subsequently exploit commercially. We are really looking forward to this being possible now that we have this ERC funding."