Improvement of recorded holographic fringes by feedback control

A feedback control system has been designed to stabilize the position of interference fringes, particularly those which occur in holography. The result of closed loop operation of the system is that rather severe phase perturbations may occur in either of the beams, and yet be compensated for such that the fringes in the holographic recording medium are essentially stabilized. This paper discusses the design and analysis of an experimental model and its performance for phase perturbations due to acoustic and mechanical vibration, thermal drift, large perturbations, warm air turbulence, and small doppler shifts. The authors then speculate that more advanced designs may stabilize interference fringes even with larger phase perturbations such as large doppler shifts, optical frequency differences, motion of the scene, and holographic interferometry.