Control and measurement of electric dipole moments in levitated\n optomechanics

Abstract

Levitated optomechanical systems are rapidly becoming leading tools for\nprecision sensing, enabling a high level of control over the sensor's center of\nmass motion, rotation and electric charge state. Higher-order multipole moments\nin the charge distribution, however, remain a major source of backgrounds. By\napplying controlled precessive torques to the dipole moment of a levitated\nmicrosphere in vacuum, we demonstrate cancellation of dipole-induced\nbackgrounds by 2 orders of magnitude. We measure the dipole moments of ng-mass\nspheres and determine their scaling with sphere size, finding that the dominant\ntorques arise from induced dipole moments related to dielectric-loss properties\nof the SiO$_2$ spheres. Control of multipole moments in the charge distribution\nof levitated sensors is a key requirement to sufficiently reduce background\nsources in future applications.\n