Several types of microscopes are at hand for study of biological materials. Their classification is based on the types of light source used and consists of two main categories; optical microscopes utilizing visible light and microscopes that utilize sources other than visible light.
Polarizing Microscope: Many natural objects including crystals & fibers exhibit special optical property known as double refraction or birefringence. Birefringence is caused by asymmetric particles, too small to be resolved even by best possible lenses. The polarizing microscope is a conventional microscope in which a nickel prism or Polaroid sheet is interposed in the light path below the condenser. This polarizer converts all the light passing through the instrument into plain polarized light. A similar second prism know as the analyzer is placed within the barrel of the microscope above the objective lens. When the analyzer is rotated until its axis is perpendicular to that of polarizer, no light can pass through the ocular lens, resulting in a dark field effect. The field will remain black if an isotropic or singly refractive object is placed on the stage. A birefringent object, however, will appear bright upon a dark background when examined in this manner.
We recommend the 40x-1000x Trinocular Infinity Polarizing Microscope with 9.0 MP Camera