Methods for increasing the accuracy of remote measurements with twin-wave laser interferometers

Abstract

One of the most common interference schemes used for remote measurements is the optical system of the Michelson laser interferometer (LI). A modification of this is shown in the paper. Interference modulation is accomplished by periodic movement of light-splitting plate in the direction of propagation of the light beam and periodic movement is provided by a piezoceramic motion converter, which is firmly attached to the plate. As a result of periodic movements to the plate, the photoconverter produces an ac signal whose phase is related to the movement of the interference pattern. Thus, the entire subsequent measurement process involves measuring the phase of the output signal of the photoconverter. The authors analyzed the amplitude-phase relations for partial superposition of the interfering beams in the analysis plane of the photoconverter. The calculations show that remote measurements that do not require high recording accuracy for the displacements of the interference pattern can employ the optical systems illustrated in this paper, which provide an accuracy of 0.1 interference band.