Sensitive Force Measurements With Optically Trapped Micro-Spheres in High Vacuum
AuthorAtherton, David P.
AdvisorGeraci, Andrew A.
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This dissertation details our work on optically levitating and cooling microspheresin vacuum for use as force sensors. We have extensively modeled various optical trap congurations to determine stable trap geometries for m sized spheresin a dual-beam optical trap. Techniques have been developed for overcoming instabilities which occur when pumping trapped micro-spheres from low to high vacuum.We have also improved on methods for depositing micro-spheres in optical traps.We have shown that optically levitated micro-spheres are excellent force sensors.By eliminating the need to tether the spheres to a solid substrate, excellent environmental decoupling is achieved. In this work we present the realization of a N force sensitivity. The intended use for the technology developed is to extend the search for non-Newtonian gravity by several orders of magnitude at the micrometer length scale . This technology is also suitable for investigating the Casimir eectin the unexplored regime where neither the Proximity Force Approximation or the Casimir-Polder limits are valid.