Speaker
Description
At the Australian National University, we are developing an opto-mechanical torsion pendulum sensor for direct detection of Newtonian noise to help improve the low-frequency sensitivity of future gravitational wave detectors. The sensor design consists of two suspended orthogonal pendulums that rotate differentially in response to local gravity fluctuations, i.e., Newtonian noise.
Beyond Newtonian-noise characterization, the sensor concept also offers potential applications in earthquake early-warning systems and, with minor design modifications, may enable searches for certain classes of dark-matter interactions.
The instrument is currently undergoing significant upgrades, including the implementation of a multi-stage seismic isolation suspension and installation within a vacuum environment to reduce environmental disturbances. The interferometric readout system has also been improved with active laser frequency noise stabilization and opto-mechanical damping to suppress suspension resonance coupling.
In this presentation, we report the current status of the instrument, describing the key upgrades to the sensor and readout system, and present recent measurements demonstrating the performance of the low-frequency interferometric readout.