Michelson interferometer system for seismic noise measurement

Laser interferometry is one of the most sensitive and widely used techniques for small displacement measurement, whose success is mainly due its very good performances and the large availability, high quality and relatively low cost of optical components and laser sources. This technique is flexible enough to be effectively used in very different applications, like the one we present in this paper, that is a laser interferometric system prototype used to read the position of a free mirror to measure the local seismic noise. After a description of the system, its performances were compared to the ones of a standard accelerometer. The results are encouraging although some problems, mainly connected with the sensitivity and the stability of the interferometric system need a better understanding.