Improved search for new short-range forces with a levitated optomechanical sensor*

A rich landscape of theories predict deviations from Newtonian gravity at short length scales ≤10μm. Searching for such deviations is a formidable experimental challenge due to the exceedingly small magnitude of the gravitational force relative to other effects, such as electromagnetism, that lead to measurement backgrounds. Traditionally, laboratory searches for such deviations have relied on variations of mechanical oscillators. We present results from a novel platform using a levitated optomechanical sensor. For the first time, the search is done by sensing all three spatial components of force. A ∼100-fold improvement is made relative to an initial iteration of this experiment, largely attributable to better understanding, and mitigation, of various sources of backgrounds. Apart from improving sensitivity to deviations from Newtonian gravity, developing techniques to deal with such backgrounds are critical to a whole class of experiments that seek to bring matter within close proximity of levitated test-masses, such as those seeking to study the quantum nature of gravity on the table-top.