Beyond the steady-state: a time-resolved optomechanical magnetometry platform

Searches for new physics in condensed matter systems rely on ever-more-precise sensors. In the Davis Lab, we specialize in the engineering of such sensors and their application to superconducting, superfluid, and magnonic systems. As such, our platforms must be tolerant of the environments required for these searches; remaining functional from vacuum to high-pressure superfluid, from room to sub-mK temperatures, and addressable from within the cryostats needed to maintain these conditions. Our primary investigative toolkit is cavity optomechanics - leveraging the interaction between coupled mechanical and electromagnetic resonators. Despite much interest in the applications of such devices in the new quantum computing ecosystem, they are also invaluable as physics probes. In this presentation, I'll discuss a promising platform we are just bringing to bear onto thin-film superconductor physics. The mesoscopic sample regime in thin-film superconductors hosts exotic "few-fluxoid" effects, including size-dependent phase transitions and the so-called "paramagnetic Meißner effect". To date, only static studies of these phenomena have been performed. The real-time readout of high-frequency mechanical probes implies an opportunity to examine the characteristic timescales of these processes. We have designed such a sensor that is sample-agnostic and optimized for plug-and-play installation in a wide variety of cryostats. It promises superior optical performance and thermometry over comparable platforms while eliminating the need for cumbersome optical coupling apparatus inside the cryostat. I'll present our design, fabrication, and progress towards the realization of this sensing platform.