Contribution to the interferometric measurement of sub-angstrom vibrations

Abstract

A Michelson interferometer is described for the measurement of low-frequency vibrational amplitudes in the sub-angstrom range (down to 10−3 Å) as a function of temperature. For this purpose a temperature stabilizing circuit has been developed. The use of a condensor microphone as an electromechanical feedback transducer opens up the possibility to relate the amplitude measurements to the wavelength of light. By these means the accuracy, reliability, and versatility of the interferometer are considerably improved and the draw-backs of existing set ups are effectively eliminated.