Over the last 15 years his research was focused on enabling the direct observation of gravitational waves and improving the required detector technology. Stefan earned his Physics Diploma from the Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, and his Ph.D. in Physics from the Massachusetts Institute of Technology in the United States. Before joining Syracuse University he was a Millikan Fellow at the California Institute of Technology, and a visiting researcher at the National Astronomical Observatory of Japan. In 2014 Stefan spent a sabbatical at the LIGO Hanford Observatory in Washington State, commissioning the Advanced LIGO interferometer.