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2 August 2004 Design considerations and validation of the MSTAR absolute metrology system
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Absolute metrology measures the actual distance between two optical fiducials. A number of methods have been employed, including pulsed time-of-flight, intensity-modulated optical beam, and two-color interferometry. The rms accuracy is currently limited to ~5 microns. Resolving the integer number of wavelengths requires a 1-sigma range accuracy of ~0.1 microns. Closing this gap has a large pay-off: the range (length measurement) accuracy can be increased substantially using the unambiguous optical phase. The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. In this paper, we present recent experiments that use dispersed white light interferometry to independently validate the zero-point of the system. We also describe progress towards reducing the size of optics, and stabilizing the laser wavelength for operation over larger target ranges. MSTAR is a general-purpose tool for conveniently measuring length with much greater accuracy than was previously possible, and has a wide range of possible applications.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert D. Peters, Oliver P. Lay, Serge Dubovitsky, Johan Burger, and Muthu Jeganathan "Design considerations and validation of the MSTAR absolute metrology system", Proc. SPIE 5531, Interferometry XII: Techniques and Analysis, (2 August 2004);

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