Laserinterferometry for Gravitational Wave Detection
The direct detection of gravitational waves requires to measure tiny variations of space and/or time. Laserinterferometry allows us to do this with an extreme level of precision and is, hence, the baseline technology for most current and future detectors in the millihertz to kilohertz frequency band. The improvements and extensions of the achievable displacement measurements enable us to mesure more astronomical events and to learn more about them. Therefore, experimental research on laserinterferometry is a central pillar of gravitational wave astronomy and the major focus of this research group.
The frequency band from a few hertz to kilohertz can be probed with ground-based detectors. The LIGO detectors directly measured a gravitational wave for the first time in 2015, the event knows as GW150914. Since then they have, together with the Advanced Virgo detector, detected several more events. The sensitivity of the detectors is continually improved upon between observation runs to reach their design sensitivity. Our group investigates techniques to further reduce undesired disturbances, or noise, to further enhance the sensitivity and bandwidth of current and future detectors, like the Einstein Telescope. The major focus of our group is on the reduction of low frequency disturbances, especially seismic noise and parasitic light fields, so-called scattered-light.
Lower frequencies typically require space-based detectors that are not influenced by seismic or gravity gradiant noise. The Laser Interferometer Space Antenna (LISA) mission of the European Space Agency (ESA) will be the first space-based detector to measure gravitational waves in the millihertz frequency band. Research on laserinterferometry is done both for LISA and other future mission concepts. Our group focuses on the study and demonstration of new technologies and on supporting the technology developments and testing of the LISA instruments.
Precision Metrology, Quantumtechnologies & Photonics
Experimental gravitational wave detection research has a large overlap with technologies, effects and methods that are used in precision metrology (ultra-stable lasers), quantum technology (optical frequency distribution, frequency doubling) and photonics (information technology, data transfer). Our research includes methods that can be applied in all of these fields and vice-versa, to finally improve gravitational wave detection itself.