Optical metrology

thumb|upright=1.5|Comparison of photometric and radiometric quantities Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye.

thumb|An Ellipsometer at Laboratory for Analysis and Architecture of Systems|LAAS-CNRS in Toulouse, France Ellipsometry is an optical technique for investigating the dielectric properties (complex refractive index or dielectric function) of thin films. Ellipsometry measures the change of polarization upon reflection or transmission and compares it to a model.

thumb|right|upright|Synthetic aperture radar image of [[Death Valley colored using polarimetry.]]

[[File:H&D curve.png|thumb|350px|right|Page 10 of Raymond Davis Jr. and F. M. Walters, Jr., Scientific Papers of the Bureau of Standards, No. 439 (Part of Vol. 18) "Sensitometry of Photographic Emulsions and a Survey of the Characteristics of Plates and Films of American Manufacture," 1922. The next page starts with the H & D quote: "In a theoretically perfect negative, the amounts of silver deposited in the various parts are proportional to the logarithms of the intensities of light proceeding from the corresponding parts of the object." The assumption here, based on empirical observations, i

Densitometry is the quantitative measurement of optical density in light-sensitive materials, such as photographic paper or photographic film, due to exposure to light.

thumb|250px|right|T100 autocollimatorAn autocollimator is an optical instrument for non-contact measurement of angles. They are typically used to align components and measure deflections in optical or mechanical systems. An autocollimator works by projecting an image onto a target mirror and measuring the deflection of the returned image against a scale, either visually or by means of an electronic detector. A visual autocollimator can measure angles as small as 1 arcsecond (4.85 microradians), while an electronic autocollimator can have up to 100 times more resolution.

scientific instrument used to measure the speed of light

device to measure short optical pulses

Mathematical image techniques

light in an optical system unintended by design

type of optical instrument

method for measuring ultra-fast laser pulses

Autocollimation is an optical setup where a collimated beam (of parallel light rays) leaves an optical system and is reflected back into the same system by a plane mirror.

thumb|right|Microdensitometer