Photonics Dictionary

A polarizing beamsplitting prism similar in design to the Rochon prism. However, the Senarmont transmits the extraordinary ray without deviation and deviates the ordinary ray due to the orientation...

A variation of tomography, which is a means of visualizing any one of a large set of parallel planes in the patient. A series of x-ray pictures taken from different angles results in developed...

A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector specifically designed for detecting and measuring light intensity. Silicon...

Any ray through an optical system that is not a meridional ray. The plane created by a refracted skew ray does not contain the optical axis.

The investigation of microstructures by an instrument that generates a narrow, highly collimated beam of x-rays.

An array of active optical devices (modulators, laser diodes and/or detectors), each of whose electrical inputs or outputs are directly connected to electronic logic circuits, which also are a part...

A form of liquid crystal in which flow does not take place in the usual manner. When examined with polarized light, the substance often forms drops that display a series of fine lines. X-ray...

A transmission interference microscope that produces interference patterns of a sample by using birefringent plates that split a polarized beam of light into ordinary and extraordinary rays, then...

The incident ray, the normal to the refracting surface at the point of incidence of the ray at the surface, and the refracted ray all lie in a single plane. The ratio of the sine of the angle between...

A ruggedized scintillation counter used in oil well logging. The cylindrical housing contains a gamma ray source, a crystalline scintillator and a photomultiplier tube. As the sonde is drawn through...

A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of light in two dimensions, typically in the form of an array. SLMs are...

When, for example, a beam of monochromatic light passes through a diffraction grating, the emergent rays that have remained undeviated are included in the zero spectral order. The light flux in the...

A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic spectral response of a material or object across different wavelengths of the...

A high-contrast transparency of the gas sought, or an array of exit slits that correlates with some features of the spectrum. No standardized formula for positioning, number or thickness has been...

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface do not converge or diverge to a single focal point. Instead of focusing to a...

A memory system composed of a stack of holographic plates, a mode-locked laser and a rapid detector array. Ultrashort laser pulses are used to extract information from the stack. In this way, storage...

The determination of axially symmetric and asymmetric refractive-index distributions by use of interferometry carried out on the basis of the approximation of a straight path of rays passing through...

A streak camera is a specialized instrument used to capture and analyze ultrafast phenomena, such as extremely short pulses of light or rapidly changing events. Unlike traditional cameras that...

An image of an object that appears above the object's true position as the result of abnormal refraction of the image rays by the atmosphere.

An acoustic wave that propagates along the surface of a solid and decays exponentially with substrate depth. Also called a Rayleigh wave, it has both longitudinal and transverse (shear) components....

A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or positrons, in a closed, circular or elliptical path. The name synchrotron...

Radiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation occurs in the x-ray and ultraviolet regions of the spectrum. Once considered...

Optical aberration such that image magnification varies with ray distance from the optical axis in a radial distortion.

1. The anode or anticathode of an x-ray tube that emits x-rays when bombarded by electrons. 2. The screen in a television imaging tube that is scanned by an electron beam to determine the...

There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is located at the front focus, resulting in the chief rays being parallel to the...

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

A method of scanning in which a frame transfer device produces a continuous video image of a moving object by means of a stack of linear arrays aligned with and synchronized to the movement of the...

A metal box with an opal glass front enclosing a lamp, used for viewing color transparencies or x-ray films.

In a color cathode-ray tube, a grouping of three color dots (red, blue and green) that represent one pixel in the final image.

A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between the two negative lenses. With this system, it is possible to decrease...

Array used in coded-aperture imaging experiments with two-beam CO2 lasers that provide an artifact-free process, faithful reproduction of the true image, and more photon collection than the pinhole...

The angular relation between two light rays that originated at the same object point. Sometimes used to indicate the angle between the visual axes of the eyes.

With respect to a television system, a pulse transmitted at the end of each field to break off the cathode-ray beam as it begins the next field.

A display standard no longer in use and originally defined for IBM PCs, with 640 3 480 pixels in 16 colors and a 4:3 aspect ratio. There is also a text mode with 720 3 400 pixels. The standard has...

An image that is formed when rays emerging from an optical system are diverging from the optical axis. The virtual image is formed where the bundle of diverging rays appear to intersect each other...

The Weissenberg method, named after the German physicist Karl Weissenberg, is a technique used in x-ray crystallography for obtaining high-quality diffraction patterns from single crystals. This...

Specified curved optic intended for maximum collection of light, including off-axis rays, before leaving the exit aperture.

Two flat parallel electrodes that are vertically mounted alongside each other in a cathode-ray tube and produce horizontal deflection of the beam when a difference of potential is applied between...

Radiography using the emission of x-rays to form an image of the structure penetrated by the radiation.

A window made of glass containing a high percentage of lead or other dense material known to absorb x-rays readily.

The testing by hypothesizing a likely crystal structure, computing a test x-ray diffraction pattern and comparing this to the observed pattern to evaluate a crystal structure.

The series of processes used to identify and evaluate crystal structure by using crystalline solids to diffract x-rays. In the Laue method, radiation of a wide range of wavelengths is transmitted by...

The study of the celestial bodies, relative to x-ray emission. Satellites launched to study x-ray sources have revealed many new classes of galactic and extragalactic sources, as well as the...