Limitations of precision length measurements based on interferometers

The most important principles, the basis and operation of heterodyne and homodyne interferometers are discussed. Their benefits and limitations are covered based on a metrological analysis. The resolution of interferometers can be determined by calculating the smallest resolvable distance increment. Also, it is shown here how the Abbe comparator principle can be fulfilled in all three measuring dimensions by using interferometers. Other factors in addition to the Abbe errors are discussed which affect the measurement uncertainty of interferometric length measurements.The Abbe-error-free design is explained using the example of a nanopositioning and nanomeasuring machine developed at the Institute of Process Measurement and Sensor Technology (Ilmenau University of Technology) and manufactured at the SIOS Meßtechnik GmbH Ilmenau, Germany.