Editing Polarization (waves) (section)

=== Ellipsometry ===
{{Main|Ellipsometry}}
Ellipsometry is a powerful technique for the measurement of the optical properties of a uniform surface. It involves measuring the polarization state of light following specular reflection from such a surface. This is typically done as a function of incidence angle or wavelength (or both). Since ellipsometry relies on reflection, it is not required for the sample to be transparent to light or for its back side to be accessible.

Ellipsometry can be used to model the (complex) refractive index of a surface of a bulk material. It is also very useful in determining parameters of one or more [[thin film]] layers deposited on a substrate. Due to their [[Thin-film interference|reflection properties]], not only are the predicted magnitude of the ''p'' and ''s'' polarization components, but their relative phase shifts upon reflection, compared to measurements using an ellipsometer. A normal ellipsometer does not measure the actual reflection coefficient (which requires careful photometric calibration of the illuminating beam) but the ratio of the ''p'' and ''s'' reflections, as well as change of polarization ellipticity (hence the name) induced upon reflection by the surface being studied. In addition to use in science and research, ellipsometers are used [[ellipsometry#In situ ellipsometry|in situ]] to control production processes for instance.<ref name="GoldsteinGoldstein2011">{{cite book|author1=Dennis Goldstein|author2=Dennis H. Goldstein|title=Polarized Light, Revised and Expanded|date=3 January 2011|publisher=CRC Press|isbn=978-0-203-91158-7}}</ref>{{rp|585ff}}<ref name="Mansuripur2009">{{cite book|author=Masud Mansuripur|title=Classical Optics and Its Applications|date=2009|publisher=Cambridge University Press|isbn=978-0-521-88169-2}}</ref>{{rp|632}}