Heart Valve Lab - Polarized Light Microscopy Polarized light microscopy Circularly polarized light image of aortic valve cusp.
Bright regions are collagen.
Polarized Light Microscopy is a technique that relies on a material's optical properties to examine microstructure. It can be best applied to materials that are anisotropic and have two indices of refraction. When polarized light enters a birefringent material, it is split up into two rays that vibrate along the two principal directions of the anisotropic crystal lattice. One of these rays is called the fast ray, and the other the slow ray. By the time the rays emerge from the specimen, one of them has been retarded, or slowed down, more than the other and this angle of retardation can be used to deduce the microstructure of the material.