Automatic Absolute Distance Measurement with One Micrometer Uncertainty Using a Michelson Interferometer

Abstract—In this paper, we suggest a novel system that is capable of measuring absolute distances with an uncertainty of one micrometer, or better, over a distance of up to 20 meters. This system consists of a Michelson interferometer, a tunable external cavity diode laser, a wavelength meter, a digital camera and a computer. The Michelson interferometer contains a reference arm mirror, a target arm mirror, a coherent light source, a white screen and a beam-splitter. The distance between the beam-splitter and the reference arm is known a priori with one-micrometer accuracy. The distance between the beam-splitter and the required measurement target arm is initially known with only a low precision accuracy of one-millimeter. The distance between the beam-splitter and the target arm is required to be measured with one micrometer uncertainty, or better. Index Terms — Absolute distance measurement, external cavity tunable diode laser, Fourier fringe analysis, Michelson interferometer, synthetic wavelength. I