Two-dimensional measurement technique for birefringence vector distributions: measurement principle

The two-dimensional measurement principle for a birefringence vector distri bution in transparent materials is analyzed. The system nonuniformity that results from the system components makes the two-dimensional measurement pr inciple quite different from that of a point-measurement method, and the me asurement principle requires a two-dimensional analysis. A pulsed optical p hase modulation is employed to simplify the two-dimensional mathematical an alysis. As a result, concepts are proposed of the system function that char acterizes the system nonuniformity that results from the system components and of the intrinsic function that is related to the birefringence vector d istribution in a birefringent sample. The influence of the system nonunifor mity on the two-dimensional measurement is eliminated by measurement of the intrinsic function, whereas its two values allow for the mathematical sepa ration of the birefringence vector components. The effectiveness of the two -dimensional analysis is illustrated by measurement of a birefringence vect or distribution, which is induced by an internal stress distribution in a p oly(methyl methacrylate) plate, owing to the photoelastic effect. (C) 1999 Optical Society of America.