Towards Investigating the Casimir Effect in a New Regime

Abstract

The Casimir interaction is a stark quantum mechanical effect that significantly contributes to precision force measurements at the micron and nanometer scale. Our group is constructing an experiment to launch and optically trap a dielectric nanosphere in a regime where the radius and surface separation between the sphere and plate are comparable. The Casimir force between a dielectric nanosphere and metallic plate must be calculated in order to both understand its effect in the gravitational force measurement at the nanometer scale and to have a theoretical model to predict the results of the Casimir force measurement. This interaction has been previously measured for metallic plane-plane and metallic plane-sphere systems in both PFA and Casimir-Polder limits but our calculations will take place in a metal plane-dielectric sphere system for radius and surface separations comparable to each other, where the previous models produce both differing and incorrect results. To measure the force, a silica nanosphere will be launched and levitated in an optical trap where the Casimir force due to a gold plate will be measured. Due to stiction forces between them, nanospheres tend to form clumps and trapping these in the laser trap is not optimal. To reduce the occurrence of nanospheres clumping together, a system to load the nanospheres onto the diving board using a spin coater has been implemented.