Our aim is to probe current understanding of the systematic errors in these methods by means of this intercomparison. The results should include a new implementation of combined x-ray and optical interferometry, pairwise intercomparisons that have not been previously undertaken, and technology developments reducing periodic errors in Michelson interferometry. One of the final goals is to provide a calibration service for decimeter line scales extending up to 500 mm. A simple Michelson interferometer is shown.
Motion is sensed by a change in the heterodyne frequency with appropriate demodulation electronics.
Figure 2 shows a simple heterodyne interferometer in which the quiescent frequency is set by the difference between the frequencies at which two acousto-optic modulators are driven. The main strength of Michelson interferometry is its simplicity. Owing to its simplicity, it is relatively easy to multiplex and create a set of multiple Michelson interferometers to probe multiple degrees of freedom of a target object. The systematic errors inherent in Michelson interferometry are well known. Much of our work has been dedicated to the interpolation problem.