Photonics Dictionary

1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting direct measurement of its size. 2. Also called traveling stage and traveling...

A reference incandescent light source having a luminous intensity that is used in photometry for comparison of other light sources.

A filter used in photography to change the spectral composition of light entering a camera, or to adjust color balance during printing.

A semiconductor made up of two or more elements, in contrast to those composed of a single element such as germanium or silicon. In a III-V semiconductor, for example, one or more elements having...

A method of producing large volumes of plastic optical components in which powdered or sheet plastic is pressed between heated dies.

The phenomenon observed by A.H. Compton in 1923 -- that some scattered radiation possesses a longer wavelength and correspondingly smaller frequency than the incident radiation. It may be described...

Computational imaging refers to the use of computational techniques, algorithms, and hardware to enhance or enable imaging capabilities beyond what traditional optical systems can achieve. It...

A snapshot representation of the final image created by a computer program.

Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision machining tools to remove material from a workpiece. In CNC grinding, a...

A technique used to store wavefront information on thin polarization information-recordable materials by controlling the polarization angle of a small illuminating spotlight in each sampling cell on...

Computer vision enables computers to interpret and make decisions based on visual data, such as images and videos. It involves the development of algorithms, techniques, and systems that enable...

The use of computer analysis in the calculation of diffraction patterns for information on the design of optical systems. In this method, the electric field amplitude and phase in the aperture are...

A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than traditional optical techniques. CGHs are generated entirely in digital form...

A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density level during laser materials processing. These devices direct and focus...

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

The generation of a grating on a concave spherical blank by the holographic process. In this way, ghost images and intense stray light are avoided.

A lens having surfaces whose centers of curvature coincide.

1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from or converging upon a point are sometimes referred to as a cone of light. 2....

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

A device used to determine the location and attitude with respect to the Earth of orbiting spacecraft by detecting the difference in thermal radiance between the Earth's horizon and space.

A system that determines whether an image is in or out of focus by means of a source of illumination at the conjugate focal point, which reflects off the target; the return beam is mediated by masks...

Also known as real holographic image. The indistinct, highly distorted image produced on the side of the hologram closest to the observer, in addition to the primary image. When the location of the...

A connectome refers to a comprehensive map or diagram of neural connections within the brain or nervous system of an organism. It encompasses all the intricate pathways formed by neurons, including...

Hardware installed on fiber cable ends to provide cable attachment to a transmitter, receiver or other cable. Usually a device that can be connected and disconnected repeatedly.

An optical instrument, generally a polarizing microscope, that is used to determine the interference figures and optical axis of a sample crystal. Also called a hodoscope.

Method of disk rotation used for optical disk drives, in which the spindle motor decreases the speed of the disk's rotation as the head moves from the inner tracks to the outer, so that the radial...

A fluorographic method whereby the sensitive photographic medium is pressed against a fluorescent screen to form a visible image.

The maximum number of users who are using a given communication channel. Typically, the number of users at any given time is below this maximum, with the contention rate representing a worst case...

A continuous strobe, also known as a continuous light or constant light strobe, is a type of lighting device used in photography, videography, and various other applications where continuous...

Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In various contexts, the term is used to describe continuous, uninterrupted...

A laser that emits radiation continuously rather than in short bursts, as in a pulsed laser.

A method in optical character recognition in which a mobile light beam scans the outlines of characters for subsequent reading of these outlines.

Selection of specific brightness values or minimum threshold levels as contingencies for the display of digital data.

The generation, usually by a cathode-ray oscilloscope, of a two-dimensional image having a three-dimensional appearance.

The apparent difference in brightness between light and dark areas of an image. For a light target against a dark background, contrast is computed as follows: where Lt is the luminance of the...

A filter designed to improve contrast in an imaging system. For visual and black and white photosystems, a yellow filter is used.

That contrast level that exists between two areas whose difference in brightness is just perceivable.

A type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small, concentrated spot at a specific point in front of the sensor. Also referred...

A telephoto lens form noted for its lack of distortion.