Photonics Dictionary

A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture...

A system that generally uses a photodetector to decode punched cards for information, or for input to a computer, by sensing the light transmitted through the punched holes.

Of or pertaining to the methods of the French philosopher Rene Descartes. Refers to the standard orthogonal X-Y-Z coordinate system.

The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged conductive surfaces. This force arises from the quantum vacuum fluctuations of the...

Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the form of light, into an electrical signal. Photocathodes are components used in...

Catoptrics is the field of optics concerned with the reflection of light from reflective surfaces such as mirrors. It encompasses the study and analysis of how light rays interact with these...

A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images into electronic signals. It is a key component in digital cameras, camcorders,...

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of the system. 2. The machining (edging) of the outside diameter of a lens...

In the SI system, prefix meaning one hundredth, 10-2.

Centration is the precise alignment of the optical center of a lens or optical element with its mechanical center or the axis of the mounting assembly. It is crucial for ensuring that the optical...

An isotope of cesium that emits negative beta particles and has a half-life of 2.19 years; its applications include photoelectric cells and developmental ion propulsion systems.

A cathode-ray tube that generates symbols for use in other displays. The tube operates by scanning specific characters on the target and generating them as video signals to other cathode-ray systems.

Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor deposition, a technique for depositing thin films of various materials onto...

The ray that passes through the center of the aperture stop in an optical system. It often is called the principal ray of an oblique beam.

Chirped mirrors are optical devices designed to manipulate the spectral properties of ultrashort laser pulses. They consist of multiple layers of dielectric coatings deposited on a substrate, where...

Chirped pulse amplification (CPA) is a technique used in laser physics to amplify ultrashort laser pulses to high energies without causing damage to the amplifying medium. The method was first...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

Proportions of standard primaries (tristimulus values) required for a color match; ratios of each tristimulus value of a color to their sum. In the CIE colorimetric system, designated X, Y and Z.

The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in an optical system.

A type of spectroscopy used extensively in the analysis of biological samples. Because most biologically synthesized molecules, such as proteins, are optically active, circular dichroism spectroscopy...

The limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an individual component. Also known as free aperture or objective aperture. The...

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

A defect in an optical system that prevents rays from reaching their intended destination; it can be caused by an undersized aperture, a baffle out of position, etc. In imaging applications, removing...

A closed-loop system that compensates for thermal blooming by optimizing only one parameter: the amplitude of the phase correction.

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...

That length over which energy in two separate waves remains constant. With respect to a laser, the greatest distance between two arms of an interferometric system for which sufficient interferometric...

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...

A coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers arranged in a specific geometric pattern to maintain the spatial coherence of...

The manifestation of light from scatterers outside the plane of the object in coherent light systems. The output of these systems is often marred by this noise.

An optical instrument used to determine the distance to a target being viewed. Two similar optical systems view the target via 45° mirrors at the ends of a fixed baseline. One system creates the...

A means of illumination from which the infrared component has been removed by absorption or reflection filters within the condenser system.

Category inclusive of all radiation that is incited electronically, except laser radiation, as a function of the application of laser power to a system.

The solid angle of a detector or system pupil as seen by the source.

A convex or positive lens that serves to collect energy and direct it into subsequent system optics.

1. The process of aligning the optical axes of optical systems to the reference mechanical axes or surfaces of an instrument. 2. The adjustment of two or more optical axes with respect to each other....

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 reduction in longitudinal, lateral and secondary chromatic aberrations in a lens or lens system.

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.

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...