Towards an optomechanical torque magnetometry platform for detection of individual superconducting vortices.

Cavity optomechanics presents a powerful toolkit for performing high-resolution measurements, with measurements pushing up against the standard quantum limit and even being used to demonstrate quantum behavior of mechanical resonators. However, despite this sensitivity, there have been relatively few applications of optomechanics techniques to the study of fundamental condensed matter questions. We present an optomechanical platform for the investigation of superconducting thin films. Our sensor is cryogenically compatible and enables direct fiber-coupling inside a dilution fridge, mediated by an on-chip waveguide. It is sample agnostic, allowing the investigation of many superconducting materials. Using a torsional element with mechanical resonance frequency in the MHz regime, we anticipate time-resolved magnetometry and real-time observation of the creation and annihilation of vortices in superconducting films. The geometry of the sensor is optimized for torque-mixing resonance spectroscopy, further allowing us to probe the dynamical behavior of such vortices.