Photonics Dictionary

In a visual optical system, the axial distance from the last mechanical surface of the eyepiece to the exit pupil.

Denoting a finished circular edge. A decentered lens is adjusted on a centering chuck so that its image runs true, and the lens is then edged. A circular edge is one that has been cleared out....

Also called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.

The application of photography, with the exception of radiography, to obtain pictures of parts or the whole of a patient to make a diagnosis.

In morphological image processing, a series of dilations followed by the same number of erosions.

A CMOS camera refers to an imaging device that employs a complementary metal-oxide-semiconductor (CMOS) image sensor to capture digital images. CMOS cameras have become ubiquitous due to their low...

A CMOS image sensor, short for complementary metal-oxide-semiconductor image sensor, is a type of semiconductor device used to capture visual information and convert it into electrical signals for...

A method of improving the signal-to-noise ratio of an interferogram by adding another interferogram to it.

An imaging process in which the single opening of a simple pinhole camera is replaced with many openings called, collectively, the aperture. The recorded picture, which consists of many overlapping...

A plane mirror mounted on a polar axis that lies parallel to the plane of the mirror. When the mirror is rotated once in 48 hours, celestial objects can be made to appear stationary and are...

Coherent anti-Stokes Raman spectroscopy (CARS) is a powerful technique used in spectroscopy to probe molecular vibrations in a sample. It is based on the Raman effect, which involves the inelastic...

A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser produces an optical wave that is modulated in amplitude, phase or frequency by...

The use of phase conjugation or other methods to increase the power density of a laser beam under adverse atmospheric conditions.

Radiation in which the phase relationship between any two points in the radiation field has a constant difference, or is exactly the same in either the spatial or the temporal mode throughout the...

Cold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to nanokelvin (nK) range, close to absolute zero (0 Kelvin or -273.15°C). At...

A cathode that emits electrons, not with the influence of heat radiation, but by means of a high-voltage gradient at its surface.

A method of applying antireflection coatings to optics that avoids the elevated temperatures normally used. A cold coating will not be as durable as a normal coating.

A mirror whose coating serves to reflect visible radiation while transmitting the infrared.

That part of an infrared detector-Dewar assembly that limits the solid angle viewed by the sensor; it is maintained at a uniformly cold temperature so that no thermal energy is emitted. Also known as...

The application of coating without heating of the substrates.

A ring dye laser that uses prisms and a saturable absorber within the laser cavity to shape and shorten the pulses generated. Counterpropagating modes oscillating simultaneously in the ring...

An optical instrument consisting of a well- corrected objective lens or mirror with a light source and or object/image (i.e. illuminated slit or retical) at its focal plane. Collimators are used to...

A method of exciting a laser by coupling it directly to another laser.

A method of lasing in which free electrons in a laser-produced plasma collide with neonlike ions to excite electrons to states that decay at different speeds, producing a population inversion.

A colloid is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. The particles in a colloid are larger than those in a...

Colloidal quantum dots (CQDs) are nanometer-sized semiconductor particles that are dispersed in a colloidal solution. These quantum dots have unique optical and electronic properties due to their...

A test used to measure the degree of fading of different colored materials, especially those involving organic dyes, which tend to fade when exposed to bright sunlight, to a damp atmosphere or to...

A color center, in the context of materials science and condensed matter physics, refers to a specific type of crystallographic defect in a crystalline structure that introduces color to the...

1. A device used in chemistry to compare the colors of solutions held in flat-bottomed tubes and viewed along the length of the tube. Often a solid glass plunger is moved along one of the tubes to...

The transmission of a color photograph by separating the colors into varying intensities of red, blue and green, and then sending separate transmissions of the three color signals to a receiving...

The recording of three or more separate holograms having a different color on a medium, so that illumination with a tricolor beam yields three separate wavefronts, each representing one of the...

Equipment for testing an observer's color vision. Some tests require the identification or ordering of colored samples. The commercially available examples include: the Ishihara plates, on which...

Film that produces color negatives or transparencies by the use of three emulsions, one coated over the other, that are each sensitive to one of the colors red, blue or green.

An instrument that uses a beam of light to scan a color transparency, and three differently filtered photosensors to record the transmitted beam, as a means of producing three exposed separation...

A television system that is capable of producing an image whose colors approximate the colors of the original, by the use of additive color mixing of the three primary colors.

A device containing two photocells behind deep red and blue filters to measure color temperatures. The amplifier gain is adjusted to give a set reading of one photocell; the reading of the other is a...

Color vision refers to the ability of organisms to perceive and distinguish different wavelengths of light as different colors. It is a sensory ability that allows humans and many other animals to...

A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides objective and standardized color information, typically expressed in terms...

A photometer that uses a set of color filters to measure the intensity of light in various regions of the spectrum.

Colorimetry is the science and technology of quantitatively describing and measuring colors. It involves the precise evaluation of color attributes such as hue, saturation, and brightness, using...

The chromatography method in which the stationary phase is supported in or on an inert packing in a column, through which the mobile phase passes.

A lens aberration, resulting from different magnifications in the various lens zones, that occurs in that part of the image field that is some distance from the principal axis of the system....

The heat-treating method in which the index of refraction of glass is fixed near or at its maximum value by holding the glass for different periods at suitable degrees of heat below the range of...