High-precision Absolute Distance Measurement using Frequency Scanned Interferometry

In this letter, we report high-precision absolute differential distance measurements performed with frequency scanned interferometry (FSI). Absolute differential distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two new multi-distance-measurement analysis techniques were developed to improve distance precision and to extract the amplitude & frequency of vibrations present during measurements. Under laboratory conditions, a precision of 50 nm was demonstrated for a differential distance of approximately 0.7 meters. c © 2004 Optical Society of America