The topological design of a detector that allows for increased target speeds in a single-beam multi-DoF homodyne displacement measuring interferometer

Three Degree-of-Freedom (3DoF) Displacement Measuring Interferometers (DMIs) are typically used in stage metrology to measure parasitic yaw and pitch rotations in addition to the intended relative displacement. Measuring these parasitic rotations allows for the correction of Abbe error, decreasing measurement uncertainty. An area image sensor as detector in a homodyne single-beam interferometer allows for simultaneous measurement of yaw, pitch and relative distance by capturing the fringe pattern of two laser beams interfering at a relative angle. Utilizing this technique for stage metrology is currently not feasible due to the limited frame rate of an area image sensor, restricting maximum target speed to the mm/s range. Here, a novel algorithm is presented that achieves sub-nm and sub-µRad resolution using the data from only a single line of pixels. This allows using line image sensors, which are typically 10-100x faster compared to area image sensors. Experiments using a 300.000 Hz line camera validate the expected performance of this algorithm. The realization of custom MHz line image sensors will allow for 1 m/s target speed with manageable power dissipation. 36 ferometrische Sensoren T Christof Pruß T