Un-polarized light transmission DIC microscope

Abstract

A new technique for creating Differential Interference Contrast (DIC) images of transparent specimens, using un-polarized, white light is discussed. A Sagnac interferometer (SI) is used in the image space of a transmission DIC microscope to produce small/differential laterally sheared, coherent beam components that interfere to form DIC images. Phase shifts between the exit beam components are introduced by applying small angular rotation of the SI in its own plane. Results obtained for a transparent watermark on a glass slide are presented. Most important advantage of the technique is that the birefringence of a test specimen does not affect the DIC images as un-polarized light is used.