A Method for Measurement of Gravitational Acceleration by Using a Fabry-Perot Interferometer

Abstract

A method of absolute gravity measurement which utilizes a Fabry-Perot interferometer with two retroreflectors and two beam splitters is proposed and theoretical evaluation and some preliminary experimental results are shown. The method consists of 1) throwing up the lower corner reflector successively by using an acceleration produced by piezoelectric ceramics, 2) controlling the position of the upper corner reflector in order that the optical path length in the interferometer should be constant, and 3) measuring and analyzing the signal fed to the piezoelectric ceramics which control the upper corner reflector. It has a sensitivity of 10−9 in the gravitational acceleration with falling distance of less than only 1 mm, if beam splitters with large transmission coefficient and corner reflectors with large reflection coefficient are available. Preliminary experiments showed that the Fabry-Perot interferometer had characteristics as theoretically predicted although the sensitivity for the gravitational acceleration is not very high compared with an ideal case owing to beam splitters of medium transmission coefficient. This method is suitable for unmanned automatic measurement of gravity such as on the surface of the planets since it requires less mechanical motion.KeywordsBeam SplitterTransmission CoefficientGravitational AccelerationOptical Path LengthPiezoelectric CeramicThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.