Optomechanical sensors for dark matter, axions, and gravity

Optomechanical sensors have achieved impressive levels of sensitivity, enabling the detection of gravitational waves, and have advanced into the quantum-limited regime limited by the measurement imprecision associated with shot noise or the backaction from radiation pressure shot noise. Optically levitated particles exhibit extreme decoupling from the environment, making them excellent sensors of small forces, torques, or accelerations.   Optomechanical detectors can be used to search for dark matter over a wide range of energy and mass scales as well as to search for gravitational waves at high frequency. In this talk, I will present recent experimental constraints on ultralight scalar dark matter using cryogenic optical cavities. I will also discuss progress on our efforts towards using optically levitated particles for tests of gravity and to search for high frequency gravitational waves above the frequency band accessible by ground-based laser interferometer observatories. Finally, I will describe new prospects for using high-mass levitated optomechanics in the search for ultralight dark matter.