Output details

Absolute distance measurement with micrometer accuracy using a Michelson interferometer and the iterative synthetic wavelength principle.

This paper presents a new use of synthetic wavelengths in absolute length interferometry. A low precision “seeding guess” is progressively improved via an iterative technique to produce high precision results. Final accuracies of better than ±2μm over 300mm are demonstrated with the potential to reach 20m.

This novel idea is significant because it: allows automated measurement, does not require continuous line of sight and can be realised with entirely commercially available components. A further novel feature is the use of Fourier analysis to determine the residual phase fraction. Applications are being developed in the high precision manufacture of large structures.