Nonlinear Interferometry: Optical Image Addition/Subtraction and Novelty Filters.

摘要

This thesis investigated the performance characteristics of a beam fanning novelty filter and designed a switchable optical image adder/subtractor. The filter spatial resolution, contrast ratio, onset time, and velocity response were measured for both z-cut and 45 deg. cut BaTiO3 crystals in the beam fanning configuration. Experimental results show that the special 45 deg. cut crystal produces the best overall beam fanning novelty filter. In addition, switchable optical image subtraction and addition were demonstrated for the first time using a modified Michelson interferometer configured with a phase-conjugating mirror and an adjustable length leg. The system demonstrated addition and subtraction with one-dimensional and two-dimensional images. The adder/subtractor can be switched from coherent subtraction to incoherent addition by biasing a set of e-o crystals which switches the beam in one of the legs of the interferometer into an extra length. The extra length is greater than the coherence length of the laser so that incoherent addition results. The thesis concludes with a brief discussion of industrial and military system applications of the novelty filter and adder/subtractor.