Growing Crystals: Under Cross-Polarised Light.
Polarized light microscopy is an optical microscopy technique involving the use of light polarization. Simple techniques include illumination of the sample with polarized light. More complex microscopy techniques include differential interference contrast microscopy and interference reflection microscopy.
These illumination techniques are most commonly used on birefringent samples where the polarized light interacts strongly with the sample and so generating contrast with the background. Polarized light microscopy is used extensively in optical mineralogy.
This optical microscopy technique is capable of providing information on absorption color and optical path boundaries between minerals of differing refractive indices, in a manner similar to brightfield illumination, but the technique can also distinguish between isotropic and anisotropic substances.
Furthermore, the contrast-enhancing technique exploits the optical properties specific to anisotropy and reveals detailed information concerning the structure and composition of materials that are invaluable for identification and diagnostic purposes.