Photonics Dictionary

An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an image intensifier and a charge-coupled device (CCD) sensor to achieve...

A CCD image sensor that uses a proximity-focused image intensifier to provide greater sensitivity at low light levels.

A standard direct-readout vidicon tube linked by fiber optics to an intensifier for increased sensitivity.

Flux per unit solid angle.

An interferometer that functions by first detecting the light striking each aperture and then combining the two detector outputs. With an intensity interferometer, the primary collectors need not be...

The process in which the electron beam of a cathode-ray tube varies in intensity in accordance with the magnitude of the signals it receives.

A type of fiber optic sensor that responds to a change in the intensity of received light caused by the displacement or other phenomena being measured.

A lens that has a mount, usually bayonet or screw type in design, that can be used on a camera in place of lenses with the same mounting. This allows one camera body to be used with lenses of...

The ratio of the radiant power transmitted to the second surface of a medium to the corresponding radiant power that has just passed through the first surface. Internal transmittance does not denote...

A lens that is implanted within the eye to replace the eye lens, which has been removed because of cataract or other defect.

A photodetector composed of a photoconductive material that, when exposed to radiation, conducts without the aid of added impurities and does not have to be cooled to the level of extrinsic material....

Loss intrinsic to the fiber caused by parameter (core dimension, profile parameter) mismatches when two nonidentical fibers are joined.

The absorption of a photon raising an electron across the forbidden gap from valence to conduction band of the semiconductor where conductivity is increased and incident radiation may be measured.

The photoemission that would occur if a crystal were pure and its structure perfect.

The points on a photographic negative that are of equal density.

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

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...

A visual, single-unit spectrophotometer with a biprism and a Wollaston prism. The Wollaston prism polarizes coincident images of the two halves of the entrance aperture.

Laser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to introduce genetic material into cells. This method is a type of gene delivery...

A short term for latent image intensification, a process much like hypersensitizing in photography, but used after exposure and before development of the negative.

An extensometer used to measure deformations in the thickness of a plate caused by tension, compression or other stress.

A length that denotes the size of the unit cell in a crystal lattice. With respect to the cubic crystal, this is the length of the side of the unit cell. However, a simple definition of the term is...

The mechanical structure that holds a number of individual lens elements.

A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which lenses are eventually fabricated. Lens blanks are made from various...

A rotating disc that holds several lenses of differing focal length about a diameter. Used to switch lenses in a system while maintaining focus.

One optical element of a multielement lens. See optical element.

A tool used to determine the curvature of a lens surface in terms of dioptric power. See lens watch; spherometer.

A line passing through the center of a lens surface, from edge to edge.

The production of rough glass lens blanks that are pressed while red-hot to the approximate size and shape of the finished lens, ready for fine grinding and polishing. Large companies often do their...

The metal tube that maintains the optical components of a lens in proper relationship. Some lenses are mounted in metal cells, which in turn are screwed to the front and rear of a shutter or lens...

Also known as f number, lens speed is commonly represented as the ratio of the focal length to the diameter of the lens. Lower f numbers produce brighter images.

Two or more lenses arranged to act in conjunction with one another.

Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance, quality, and characteristics of lenses. These instruments are essential for...

The ratio of the intensities of a light bundle before and after passing through the lens.

A dial depth gauge graduated in diopters; a lens measure.

A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses are commonly used in optical systems, such as cameras, telescopes,...

A hologram formed without lenses and with the object and reference points sharing the same plane. In the initial recording, each object point produces fringes having one spatial frequency across the...

Lensless microscopy, also known as computational or holographic microscopy, is an imaging technique that captures and reconstructs microscopic images without the use of traditional lenses. Instead of...

A matrix of miniature lenses, molded or formed onto a common base.

An ophthalmic instrument used to measure the magnitude and direction of the maximum and minimum powers of a spectacle lens, and mark the optical center of the lens by an ink dot. When the lens to be...

The apparent visual angle that divides intrabeam viewing from extended-source viewing.

The transfer of energy lost by radiation to the body, relative to the loss of energy per unit of path traveled.

A linear image sensor is a type of solid-state electronic device used to capture and convert light into electrical signals. Unlike area image sensors (such as CCD or CMOS sensors), which capture an...