Angular Interferometry-Resolution Enhancement Using Half-Wave Plates

摘要

Draper Laboratory is using an interferometer to monitor the rotation of an actively-controlled test platform to .01 arcsec. The resolution of the interferometer needed to be doubled in order to achieve this accuracy goal. The resolution of an interferometer can be doubled by sending the beam back to its target a second time. A method for doing this, analogous to the quarter-wave plate/plane-mirror doubling scheme commonly used in linear interferometry, was designed to double the resolution of the angular interferometer. This method used a combination of half-wave plates and retroreflectors to produce the doubling effect. Some simple, small-scale tests proved that this alternate method worked and that the use of the plates caused no discernible error. A full-scale test on Draper Laboratory test platform showed that doubling the angular resolution was practical and that .01 arcsec accuracy could be achieved. (Author)