Simon Stellmer (Bonn) - Ring lasers for rotation sensing in the geosciences

Friday 22 May 2026, 15:45 → 17:15 Europe/Zurich

Ring laser gyroscopes are highly sensitive inertial optical interferometers,
 exploiting the Sagnac effect on two counter-propagating laser beams in a
 ring cavity. Meter-sized and highly stable interferometers have been
 developed in the past 30 years and reach a resolution of 0.3 prad/s after a
 few hours of integration time. The rotation of Earth, including its
 variations, is a commonly available signal used to benchmark the performance
 of large ring lasers, which succeed to quantify variations in the
 length-of-day (LoD) and to resolve the precession and nutation of Earth's
 axis.

 Similarily, ring laser gyroscopes can also be employed in the field of
 seismology to reconstruct rotational motions in seismic wavefields. Building
 on the technology of optical clocks and gravitational wave detection, new
 developments are underway to realize so-called passive ring laser
 gyroscopes. This approach relies on an external laser referenced to the
 counterpropagating modes of a ring resonator and might allow for
 miniaturization of sensors with large bandwidth.

 In my presentation, I will trace the development of ring interferometers
 over the past 100 years, and I will highlight future developments
 specifically in the recently established DFG research unit RING.