Optical Sectioning of differential interference contrast microscopy

While developing a three dimensional measurement technique by the retardation-modulated differential interference contrast (RM-DIC) microscope, we found a problem. The problem is that the measurement range is restrict in λ because it applies weak phase approximation. To overcome this drawback, we propose a three dimensional (3-D) reconstruction method with z-axis scanning. This technique needs high optical sectioning like confocal microscopy. We investigate the characteristic of optical sectioning in DIC microscope, then, we confirm that DIC microscope has high optical sectioning, experimentally. We also confirm that RM-DIC microscope has higher one. Combining the optical sectioning of RM-DIC microscope and z-scanning, we develop a new 3-D reconstruction method. This novel technique overcomes the problem, the measurement range goes micron order. 1.