Photonics Dictionary

Description of a particle that cannot be superimposed on its mirror image.

Chirality is a property of certain molecules and objects in which they are non-superimposable on their mirror images. In other words, a chiral object or molecule cannot be exactly superimposed onto...

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...

A laser whose pulses are expanded, using gratings and optical fibers, before amplification and compressed to increase beam intensity without damage to the optical train.

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...

A rapid change, as opposed to a long-term drift, of the emission wavelength of an optical source. Chirping is most often observed in pulsed operation of a source.

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.

Best point of focus for an image in a beam of light at the smallest cross section of the beam.

The optical phenomenon in which right circularly polarized light transmitted by an active medium travels at a different velocity than that of left circularly polarized light.

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...

Circular dichroism (CD) is a spectroscopic technique used to study the structural characteristics of chiral (asymmetric) molecules, particularly biomolecules like proteins, nucleic acids, and certain...

Scanning characterized by the generation of a plane or right circular cone with a vertex angle of about 180° by the direction of maximum radiation.

An optical interference coating, vacuum-deposited on a circular substrate, whose transmission characteristics may be varied by physical rotation.

A light beam whose electric vectors can be broken into two perpendicular elements that have equal amplitudes and that differ in phase by l/4 wavelength.

A passive device, having three or more ports, in which input light from one port is coupled only to the next sequential port in a given direction and is prevented from traveling in any other...

The halo phenomenon of a brightly colored arc having the colors of the rainbow and lying parallel to the horizon.

A television system that does not broadcast television signals but transmits them over a closed circuit.

Electronic circuit capable of distinguishing the pulses emitted by separate counters in a given time phase and determining whether the pulses were emitted by the same particle or correspond to a...

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

An early graphic scheme of colors in which saturated spectral colors are plotted around the circumference of a circle. Complementary colors face each other across the circle's diameter.

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 coupled pairs of electrons that carry supercurrents through the body of a superconductor, relative to a coherent macroscopic wave function with the superconductor.

Fine lines, wires or threads used in the focal plane of many optical instruments to point out and locate particular objects in the field of view. They were formerly made from a single strand of...

A cryogenically cooled long-wave infrared (LWIR) camera is a specialized thermal imaging device designed to detect infrared radiation in the long-wave infrared spectrum, typically ranging from 8 to...

A telescope similar to the customary Cassegrain telescope, but having a primary mirror that is ellipsoidal and a secondary that is spherical.

A multilayer coating that manifests both a low radiant reflectance and radiant absorption.

The circuit that regulates an electron beam's deflection in a cathode-ray tube.

A spatial light modulator consisting of a metallized polymer film stretched over an array of metal-oxide semiconductor field-effect transistors (MOSFETs). Each mirror element in the film can be...

A mirror coated to reflect cold (white) light while transmitting hot (infrared) energy.

A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that selectively reflects or transmits light based on its wavelength. Dichroic...

In a fiber optic transmission system, the conversion of received optical pulses directly to an electrical signal.

Light produced by visible radiation that moves from the light source to the object without reflection. With respect to microscopy, this is the light that directly strikes the stage of the microscope...

Also called DLIP, a high-speed, high-resolution processing technique that uses high-power, pulsed laser systems to directly ablate micro- and nanoperiodic structures with different features on large...

An energy transition concerned with photons alone.

A ray that travels from one point to another without being reflected or refracted.

A write-once optical disc storage system in which the optical head reads continuously while writing to check the accuracy of the stored data. Data recorded erroneously are then rewritten at another...

A scanning technique in which the object is illuminated the entire time, and in which picture elements of the object are viewed singly by the television camera.

In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus, the recording medium is inserted in place of the screen.

Light transmission involving no scatter.

A viewfinder whose optical system forms a direct image of a subject, as opposed to those systems that use reflectance in the image formation.

The observation of a reproduced television picture on the face of a cathode-ray tube.

With respect to atomic fluorescence spectroscopy, the fluorescence that is emitted by an atom at a spectral line of a wavelength that is longer than that of the stimulating radiation.

A cathode-ray tube in which secondary emission electrons form a display of high intensity.

A small handheld instrument consisting of a slit and collimator that feeds light into a small direct-vision dispersing prism. The eye is placed behind the prism to observe the spectrum of a colored...

An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the central wavelength.