Photonics Dictionary

E.I. duPont's trade name for a material used in the jacket of fiber optic cables. It is flame-retardant, thermally stable and resistant to oxidation, ozone and radiation.

A hypercentric lens refers to a lens system where the chief rays of light from an object are directed through the center of the lens aperture, ensuring that the entrance pupil is situated at...

Hyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in certain chemical or biological substances upon undergoing a structural change....

The splitting of an element's spectral line as the result of the interactions between the electron spin and the spins of adjacent magnetic nuclei, or the presence of several isotopes in the sample...

A vision defect commonly referred to as farsightedness. Results when the image of a distant object is focused beyond the retina by the relaxed eye. The condition can be corrected by introducing a...

An eyepiece similar to the Huygenian eyepiece, but having an eye lens that is a cemented doublet and that provides more lateral color correction.

With respect to photography, the process used to increase the effective speed of an emulsion between manufacture and exposure.

Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the electromagnetic spectrum. Unlike traditional imaging systems that record only a few...

A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide range of wavelengths within the electromagnetic spectrum, typically from...

Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a hyperspectral imaging system. In hyperspectral imaging, the electromagnetic spectrum is...

This term literally means "to lag behind.'' It is quite often used to describe the residual effect that remains after the primary effect has been removed, or the lag that exists between the...

Any filter in which the range of frequencies within a chosen radius suffers no attenuation and the range of frequencies outside the radius is entirely attenuated.

A theoretical instrument conceived of as a box that receives a beam of radiation of any arbitrary polarization angle and produces a new beam, coaxial with the incident beam, having a specified new...

A system that transmits and receives identification codes to facilitate the discrimination between enemy and friend in a tactical situation.

Pertaining to the possession of photoelectric characteristics as a result of the properties of the true crystal and not of foreign materials.

In semiconductor physics and materials science, the term "III-V materials" refers to compounds composed of elements from group III and group V of the periodic table. More specifically, these...

Luminous flux incident per unit area of a surface; luminous incidence. (The use of the term "illumination" for this quantity conflicts with its more general meaning.)

Source of radiation defined or specified by its spectral power distribution.

A magnifying lens fitted with a battery-operated lamp by which an object can be conveniently illuminated during observation.

The general term for the application of light to a subject. It should not be used in place of the specific quantity illuminance.

Generally, the orientation of rays of light striking a surface.

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

In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is passed through a system of optics and onto an image forming plane. Light rays...

An electro-optic system using, in general form, an evacuated glass envelope with a semitransparent photocathode at one end and a luminescent screen at the other for the amplification of an optical...

Often referred to as the geometric center of a given image or image plane, the centroid of an image is a fixed point located at the intersection of all of the hyperplanes of symmetry within that...

Also referred to as image visibility, the contrast of an image is the variation in the intensity of an image formed by an optical system, where the image pixels are defined on a gray scale scheme of...

An electron tube that employs electromagnetic radiation to produce a visual replica of an image produced on its cathode. Electrons ejected from the cathode by the incident radiation are accelerated...

A camera that uses an image converter tube in such a way that voltage waveforms applied to internal electrodes cause the original image to be switched on and off very rapidly, thus offering time...

A machine vision technique that compares a template of the desired image (the correlation kernel) with the actual camera image of an object and generates a new image (the correlation image) that...

In computer graphics, the coordinated two-dimensional or three-dimensional area of increased resolution where graphics entities may be defined. The screen represents a viewing window for this area,...

An electron tube that is used as a camera tube for a television system. When the picture to be transmitted is focused on a photosensitive surface, electrons are emitted from each section of the...