Photonics Dictionary

The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from superficial layers in the surface of a material.

A mechanical device designed to smoothly vary the effective diameter of a lens, thereby controlling the amount of light allowed through.

The adjustable membrane located just in front of the crystalline lens within the eye. The iris gives the eye its color. See also iris diaphragm.

One of a number of nuclides characterized by an identity between their mass numbers, but each having a different atomic number.

1. Lines of the same color. 2. A term used in photoelastic stress analysis to refer to the interference fringes produced in birefringent materials.

A graphic depiction of the loci of all points in space relative to a laser transmitter at a specific altitude.

In the context of electronics and optics, an isolator refers to a device that allows the transmission of signals in one direction while attenuating or blocking signals in the opposite direction. The...

An enclosure for a calorimeter that allows measurement of unusually low quantities of power and energy.

Lines of equal atmospheric attenuation in a laser beam.

That property of a material that determines that velocity of propagation within the material is the same for all directions.

The outer material that surrounds and protects the buffered and unbuffered fibers in an optical cable.

The higher throughput obtained with an FTIR device compared with traditional spectrometers that need slits to achieve resolution. The advantage differs according to wave number and resolution.

Phrase applied to any noise of extraterrestrial origin, named for the engineer who discovered the phenomenon.

A device to hold and locate a workpiece as it guides, controls or limits a cutting tool.

Also called coating jig allowance. That margin on an optical component that is outside the clear aperture for use in holding the component in the optical thin-film coater tooling during the...

An optical instrument containing a gimballed sighting telescope, used to measure angular relationships in horizontal and vertical planes.

A design for bent crystal monochromators in which spacing is constant along any circular arc terminating at the two foci and with equally spaced Bragg planes curved about only one axis.

The graph of a curve describing the spectral irradiance of extraterrestrial sunlight.

A device consisting of two optical systems in which two signals are simultaneously transformed to produce their spectra, and these spectra are multiplied and inversely transformed to produce the...

Characteristic of radiation detectors that produce energy that is similar to the energy of superconductive gaps when interacting with photons.

A unit of energy or work in the MKS system of units. One joule is equal to 107 ergs.

A detector cooling device in which a gas under high pressure escapes through an expansion valve in the tank; as the escaped gas liquefies, it cools the site of the sensor.

A small defocused Galilean telescope mounted in a hole in a door. Viewed from inside through the positive lens, a wide-angle view of the outside is seen; viewed from outside through the negative...

A semiconductor device with the property of conducting current more easily in one direction than the other. It has two terminals containing a single crystal of semiconducting material that ranges...

In an interlaced scanning electro-optical system such as television, the system resolution will be less than the number of active scan lines because of the random phase nature of the object being...

An eyepiece consisting of a planoconvex field lens and a cemented doublet as the eye lens.

The SI unit of temperature equal to 1°C. See absolute temperature scale.

The material lost during a laser cutting or machining operation.