Torsion Balance Investigation of the Casimir Effect

The presence of finite energy in quantum vacuum has profound implications to physics at the microscopic and macroscopic levels. One of the direct consequences of vacuum energy is the Casimir Force, which is a force of attraction experienced by a pair of infinite planar conductive plates placed in vacuum. Experiments to measure Casimir force have been carried out since the 1950s. This thesis presents a measurement of Casimir force between a flat and a spherical conducting surface using a torsion balance for separations in the range of 1 micron to 8 micron. The details of the construction of the torsion balance apparatus, the experimental procedure and the analysis to obtain the Casimir force as a function of separation are described. There are indications of the finite temperature effects which become important for separations greater than ~ 3microns. The combined import of this experiment with others at shorter distances is to favor the finite temperature theory of Casimir forces. The contributions of this experiment towards bounding the strength of inverse square law short-range violating interactions are presented.