Differential Interference Contrast (DIC) Operation

There is a sequence to using the DIC:

Image: DIC Description


Secure the prism mount slide with the lock screw engaging the prism slide detent.

Looking through the optics port, rotate the prism slide knob until the prism is centered in the port (total lateral motion is about 5mm).

Loosen the lock screw holding the prism mount slide until it is out of the detent. Pull the prism mount slide back until it stops. This clears the optical path.

Put the system together per the illustrations below (exact configuration will depend on equipment selected). Look at something highly reflective. With a 10X objective, 1X Adapter, and 1/2" camera, you will have to zoom up to at least 0.8 to get rid of any vignetting. This varies with the objective (like any ultra-zoom system). The analyzer (1-60816) will rotate something larger than 90 degrees. Loosen the analyzer mounting set screws, and rotate the analyzer so that the middle of this 90 degree rotation is located at the point of extinction (everything goes nearly black). Re-tighten the set screws. Leave the analyzer where it is and go to the polarizer (1-60812). Loosen its set screws and rotate the fiber optic holder (which has the polarizer in it). You are trying to get the maximum extinction (most black). By rotating the analyzer a little, it may help to find this "maximum black" condition. Lock the polarizer set screws. (This must be done with the prism out of the light path).

Rotate the analyzer 45 degrees and you will have a clear image. If a zoom system is employed, set the front (at high magnification) and back (at low magnfication) conjugates so the image stays in focus throughout the zoom range. The closer everything is working to nominal, the better the end results.

Rotate the analyzer back to the extinction position. Slide the prism into the path. Use the slider knob to move the prism to bring out the detail. Because the DIC is creating the "3D effect" by angled rays, details may be emphasized by rotating the object with respect to the prism system. Sometimes it helps to tweak the analyzer.