Microscope adapted for the generation of various contrast types: theory and experiment

With the aid of a polarizer, an analyzer, and two birefringent double plates placed in conjugate positions at the front focal plane of the condenser and the rear focal plane of the objective, respectively, a microscope is adapted to generate in a pure form one of four contrast types, i.e., either phase or amplitude differential or nondifferential. The theory of such an arrangement is discussed, and some practical results are shown.