Rapid electromechanical phase shifting in differential holography

摘要

Procedures for the rapid and precise control by electromechanical means of the reference beam phase shift during differential holography are described. Phase shift is created with the use of a piezoelectric ceramic translator that is driven by a twohyphen;step voltage pulse to minimize mechanical ringing. The resultant suppression of resonant vibration permits an order of magnitude reduction in the time interval between the exposures. The adjustment of the phase shift signal is assisted by use of feedback control arrangement to stabilize an interferometer.