Photonics Dictionary

Pertaining to the measurement of the intensity of light.

A prism used in a photometer for the adjacent comparison of separate luminance.

Photocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter readings are used to express illuminance and, by calibration, to measure...

The graphed curve illustrating the directional reflectance of a sample for different angles of collection.

The detection and measurement of spectral reflectance, spectral transmittance or relative spectral emittance, relative to wavelength.

A heterochromatic photometric process using successive comparison of similar chromaticities and the calculation of relative luminances of unlike chromaticities as the product of ratios of luminances...

An enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect and measure the presence of specific substances, such as antibodies, antigens, proteins, hormones, or other...

A photometric instrument used to measure the illumination falling on a surface. It may be photoelectric or visual.

A photometric instrument having two prisms clamped in optical contact to produce a photometric field with an acute dividing line.

A photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation. This style of detector is composed of opaque photocathodes for photon to...

Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective surface appears brighter when illuminated from directly behind the...

The use of photoelectric sensors to detect and measure the intensity of a light source. This application, as compared to human observation, results in higher speeds of operation, a greater...

A form of photometric measurement, often used with light sources that are transparent or fluctuating, in which a photographic plate is used to obtain a record of a source's relative intensities over...

Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the way the human eye perceives it. It involves the quantification of visible...

A reagent is a substance or compound that is used in a chemical reaction to bring about a specific transformation or to detect the presence or absence of another substance. Reagents are employed in...

The error inherent in spectral energy or spectrophotometric quantity due to the finite dimension of the entrance and exit slits.

Spectra can be conveniently recorded on photographic film or plates. The portions that are occupied by regions of the recorded developed images on the film or plate can be determined with some...

The utilization of photometric measurement to determine the relative magnitudes of the heavenly bodies.