And now for something a little different. Cross polarization microphotography with birefringent crystals. I’ve been playing around with a fun little USB microscope for a while now. Recently I came across some microscope images of Vitamin C crystals taken using a technique called cross polarization. I will have more to say about the technique in later posts. These photographs show crystals I grew of Epsom salt, Sugar and Vitamin C. The colors in the images are true, they are not computer generated.
Home grown crystals from Epsom salt as seen in cross polarized light at about 50x. The black background is the result of the crossed polarizers blocking light from reaching the sensor. The crystals however have a property by which they rotate the polarization of light passing through them by differing amounts depending on the color of the light and the thickness of the crystals.
Here are some crystals grown from regular table sugar. The process is like making rock candy, you dump as much sugar as you can get to dissolve into hot water. Then place a few drops of the super saturated solution onto a microscope slide and wait.
This is a Vitamin C crystal seen in cross polarized light where the orientation of the two polarizers is different from the previous two images. By rotating the polarizers you change what colors of light get passed through to the camera. Here I tuned them to produce an overall reddish image, however rotating the polarizers differently can result in a rainbow of colors emerging from the crystal.