Photonics Dictionary

A measurement device used to study the structure of matter using the diffraction of electromagnetic radiation.

A color filter that is designed to gradually increase or decrease its absorption with wavelength.

A filter purposely made to be placed before a lens to render the image rather unclear.

A linear computation or algorithm performed on a selected series in the form of an input signal that produces a new series as output. The computational device may be a specifically designed...

A pixel-based computer graphics system that simulates the tools of an artist.

In image processing, a device that transforms the digital data into an analog video image that can be viewed on a monitor or printed.

An instrument used to measure expansion of solids, liquids and gases.

The logarithmic method of determining emulsion speeds developed by the German standards organization, Deutscher Normenausschuss, in which the speed of the emulsion is doubled for each increase of...

A diode-pumped solid-state laser (DPSSL) is a type of laser system that uses semiconductor diode lasers to pump energy into a solid gain medium, resulting in the generation of coherent light. This...

The adjustment of the eyepiece of an instrument to provide accommodation for the eyesight differences of individual observers. The axial distance through which the eyepiece must be moved, to provide...

A scale located on the eyepiece focusing screw and used to measure the amount of defocusing of the eyepiece in diopters. The reciprocal of the image distance in meters is a measure of the amount of...

A unit of optical measurement that expresses the refractive power of a lens or prism. In a lens or lens system, it is the reciprocal of the focal length in meters. For example, if a lens has a focal...

A telescopic system having an eyepiece, a reticle and an objective. The instrument measures wavefront power in diopters.

An optical system that uses refraction to form an image.

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

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...

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...

Directed energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often associated with military and technological applications where energy, typically...

A device that provides simple and reliable laser power and energy measurement. Essentially a heat flux sensor producing an output proportional to the power, rather than the energy input.

A colorimeter using a spinning disc made of different colored sections for colorimetric analysis.

An individual circuit component, complete in itself, such as a resistor, diode, capacitor or transistor. It is used as an individual and separable circuit element.

A mathematical transformation used in image and video compression that changes two-dimensional representation of data into data defined by the frequency content. Adapted in JPEG and MPEG standards.

A spectrum of component wavelengths whose values are separate from each other.

A complex filter that uses polarization and interference to transmit light that is nearly monochromatic.

A type of glass optical fiber that provides low pulse dispersion over a broad portion of the light spectrum and as a result can operate at 1300-nm and 1550-nm wavelengths simultaneously.

Operation in which the dispersion of a pulse limits the distance between repeaters in optical systems. Waveguide and material dispersion can make recognition of a pulse impossible.

A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion, which is the phenomenon where different wavelengths of light travel at...

The limitation on performance imposed by the distortion of a received signal rather than its amplitude or power.

A device similar to distributed feedback lasers in construction and operation, but in which the period grating that produces feedback is removed from the gain region to simplify fabrication. The...

A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth light with precise control over the wavelength. It achieves this through a...

Temperature of the blackbody having a spectral power distribution approximately proportional to the test source at all wavelengths; it follows that the two have the same chromaticity.

A spectroscope having a divided circle and a means for the rapid reversal of prisms for the measurement of refractive index of the prism for a specific wavelength.

A spectrophotometer that measures the amount of ozone in the atmosphere through a comparison of solar energy at two wavelengths in the ozone's absorption band. This comparison is achieved by...

A device used to detect and measure the quantity of exposure to nuclear or x-ray radiation, and dependent on the fact that such radiation ionizes a gas.

A spectrophotometer in which the beam emitted by the radiation source is split into beams that travel through the sample and a reference cell and are subsequently recombined to fall on the detector....

A mass spectrometer utilizing both radial electrostatic and magnetic field analyzers to improve the focusing and increase resolution.

Interferometric measurement of the interference pattern recorded when a complex object is illuminated by two laser pulses that interfere and form the pattern to be evaluated.

A mode of laser printing in which each pixel is printed four times, providing sharper lines and a continuous tone from one-quarter the amount of image data, compared with single-raster output.

An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented together.

An instrument that uses a photoelectric system to determine the size and volume of dust particles in a given unit of air.

A diffraction grating with lines and grooves formed so as to concentrate the radiation of a particular wavelength into one specified order. This device is efficient when used in the infrared region...

In image processing, the location of edges by employing templates that respond to the first or second derivative of gray-scale intensity in the neighborhood of each pixel.

A color filter, generally used in photography, to emphasize certain color tones and to modify others in a picture for a more dramatic image. A blue effect filter, for example, darkens red and yellow,...

A characterization of the throughput performance of data storage systems; the EDR is the total of data retrieved divided by the total time it takes to retrieve it, expressed as megabytes per second.