EE Special Seminar
Abstract: Vibrations reveal characteristics of biological and technical systems, and vibration behavior is often relevant for the system functionality. Tactile vibration sensing suffers from influences by the coupling to a seismic mass, limited bandwidth, and the additional masses of the sensors attached to the specimen surface. Laser-Doppler vibrometry obtains the information by evaluating the Doppler frequency shift of a laser beam scattered at the specimen and is free of these drawbacks. It has a wide range of possible applications due to a high bandwidth (up to the GHz range) and a high intensity dynamic (up to 160 dB/√Hz). We explore new interferometric sensing solutions as well as new applications, such as vibrations in biomedical systems.
Biological tissue is soft, and measuring vibrations and sound without influencing the specimen is especially challenging. One research area addresses the contactless measurement of vibrations on the human body. Recently we have demonstrated that the vibration signature, obtained contactless by laser-Doppler vibrometry on the thorax above the atrium of the heart, contains the information to measure atrium-ventrical blocks, which are essential for heart-rhythm diagnostics.
Another research area addresses vibration micro- and nanoscopy. Measuring small structures is also challenging because small structures have high eigen frequencies, short acoustic wavelengths, and high sensitivity to heating by the impinging laser beam. Thus, the required bandwidth is in the GHz range and lateral as well as vibration-amplitude resolutions beyond classical physical limits are desirable. We combine techniques from different scientific fields in order to explore new solutions for advanced vibration micro- and nanoscopes.
Bio: Christian Rembe received a diploma in Physics from the University of Hanover, Germany, in 1994. From 1994 to 1999, he was a PhD student at the University of Um in Germany where he earned a doctoral degree in Electrical Engineering. In 1999 he joined the Berkeley Sensor & Actuator Center at the University of California, Berkeley as a postdoctoral research engineer with support of a Feodor-Lynen-Scholarship of the Alexander von Humboldt-Foundation and a UC Berkeley MacKay-Lecturer Fellowship. From 2001-2014 he was the manager of the Development Optics group at the Polytec GmbH in Waldbronn, Germany. Since 2015, he has been a Professor for Applied Metrology at the Clausthal University of Technology in Germany. His interests are optics, optical measurement techniques, sensors, and MEMS.
Host: Hyuck Choo