Photonics Dictionary

A light source that does not fluctuate despite temperature changes.

A platform mount used to hold sensitive optical instruments immobile.

A plane-parallel interferometer that yields extremely high contrast over a wide range of finesse values without significantly reducing transmission.

A laser resonator in which a mode oscillating between the mirrors will converge upon the laser's longitudinal axis.

The superimposing of holographic pages in a thick, erasable storage material by changing the reference and object beams. This extends the capacity of holographic memories.

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...

A type of laser used when a great amount of power is required. Avoiding the bulk of large numbers of optical lenses, this instrument offers high-output intensity and a small emitting region at...

A reticle pattern in a surveying instrument consisting of parallel lines that can be superimposed on a calibrated rod, making possible determination of the distance from the instrument to the rod.

The determination of distance based upon the known size of an object and the size of its image at the image plane of an optical system.

In microscopy, a calibrated scale on a slide that may be viewed to determine the exact magnification factor of the microscope.

A lens whose focal length is roughly equal to the diagonal of the negative format of the camera on which it is mounted.

The refraction that would take place in an idealized atmosphere where the refractive index is reduced uniformly with height at the rate of 39 x 10-6 per kilometer.

In infrared imaging systems used for mass screening of printed circuit boards or other quality control applications, an image of an ideal component that is stored in the system's memory and then...

The combination of two waves having the same frequency and amplitude and traveling in opposite directions. Standing waves are indicated by a stationary set of nodes spaced one-half wavelength apart...

A passive coupler that distributes signals from one or several inputs among a larger number of output waveguides arranged schematically as a star configuration.

The visual examination by a trained observer of the image of a point source. Any coloring or departure from the Airy disc rings indicates the presence of aberrations in the lens forming that image.

In local area networking, arrangement of the satellite nodes around a central node through which all routing of network data takes place.

Spectrum broadening that results from the influence of an electric field.

The splitting or shifting of spectral lines or energy levels caused by the application of a strong transverse electrical field. It often is studied with a canal-ray tube that has a third electrode...

In a laser, the voltage necessary to initiate electrical discharge, somewhat higher than that needed to sustain it.

The degree to which a laser beam is aligned parallel to the housing axis.

A technique for creating optimal performance in a system by producing a specific beam irradiance distribution, usually through the use of geometric optics. A common design involves the use of ray...

The application of a constant stress to an optical fiber.

That characteristic which makes a weapon system less visible to radar, optical, acousto-optic, infrared and other military sensors.

STED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence microscopy that surpasses the diffraction limit, enabling the visualization of...

The formula that indicates the total radiation at all wavelengths from a perfect blackbody. W Total = 5.67 x 10-12 T 4(W/cm2)

The angle subtended by the mean distance of the Earth from the sun at the distance of a given star from the sun.

The utilization of photometric measurement to determine the relative magnitudes of the heavenly bodies.

The projection of the image beam by a cathode-ray tube through a mask, where it is deflected through the suitable character position in the mask and then deflected by another system to its suitable...

An optical fiber in which the core is of uniform refractive index.

A profile of an optical component, usually a fiber, in which the core is of uniform refractive index and the cladding or surrounding optical surface of a different, usually lower, index.

The observed time dependence of the transmittance of a step of radiation through a given medium.

In sensitometric testing, a series of areas progressing by equal density steps (usually the increments between steps are equal to the logarithm of the square root of two). They are commonly used in...

A type of camera that has scales or other arrangements by which successive exposures can be lined up and equally spaced on a sheet of film. It is used in the preparation of microfiche copies of...

A projection printer that is capable of reproducing a multiplicity of images from a master transparency on a single support coated with a photosensitive layer by indexing the receiving material from...

A positioning drive that rotates a fraction of a 360° turn when the motor coils are activated, resulting in linear or rotary motion. They are generally one of two types, either variable...

The unit solid angle subtended at the center of a sphere by an area on its surface equivalent to the square of the radius; the unit of solid angular measurement, often used in problems of...

Flux per unit solid angle and per unit area measured normal to the direction of propagation of the flux.

The ability to perceive binocularly the apparent depth and relative distance of objects.

A camera with two taking lenses and synchronized shutters. Two images are recorded simultaneously on separate frames, producing a three-dimensional image when viewed through the proper apparatus.