Progress towards measuring gravity on the micrometer length scale with optically levitated silica microsperes

Discrepancies between the strength of gravity and other Standard Model forces suggest corrections to Newtonian gravity at the sub-millimeter length scale. In this poster, we present progress towards the realization of a system capable of measuring gravity at micrometer length scales. In ultra-high vacuum, optically-trapped and cooled microspheres show great promise as force sensors. They are completely decoupled mechanically from their environment and can have high Q factors. We are developing an apparatus to trap and cool spheres in a combined optical dipole-cavity trap. Ultimately, with a sphere trapped in an anti-node close to an end-mirror of the cavity, Non-Newtonian gravity-like forces will be tested by monitoring the displacement of the sphere as a mass is brought behind the cavity mirror.