Sensing of Gravity with Micro-Nano Particles using Counter-Propagating Dual-Beam Optical Trap

The radius and refractive index of particles is almost unconstrained in counter-propagating dual-beam optical trap. We demonstrate a micro-nano mechanical sensor for weak gravity based on the characteristics of dual-beam in vacuum. The sensor improves the response range aN~pN and accuracy of gravity for particles. Furthermore, our work may be useful for characterizing other short-range physics such as Casimir forces.