An interference microscope is used to measure the precise optical properties of materials (e.g., birefringence) and study minute variations in surface morphology. The interference microscope is based on a Michelson interferometer, which splits a monochromatic beam of light (a single wavelength of light from the visible spectrum) into two beams, a beam that passes through the sample and reference beam. As the sample beam passes through the sample, it is slowed down relative to the reference beam. After the sample, the light waves in the two beams recombine; but in recombination, the waves interfere, either constructively or destructively, creating light regions in former case or dark regions in the latter. From the resulting bands of light and dark that make up an interferogram, we can quantitatively and qualitatively characterize optical properties and surface characteristics.