Ellipsometry

Ellipsometry is a measurement method used by scientists who want to study solid materials or the surface of solids. It works by shining polarized light on a thin slice of a material and then looking to see how the nature of that light is changed when it is reflected by the sample.
Ellipsometry can be used to investigate different thin films of many different materials, of organic or inorganic origin. Inorganic subjects are things such as metals, semiconductors, insulators and also liquid crystals.
The frequency range used covers not just visible light but whole the spectrum from the microwave range, the terahertz range, infrared light, visible light up to the range of ultraviolet light.