Photonics Dictionary

A saturated compound of carbon and hydrogen used as a liquid coating material for optical components in high-power laser applications. See liquid coating.

The angular difference in the direction of an object as seen from two points of observation. The angle subtended at the object by the base length of a rangefinder.

The optical phenomenon that causes relative motion between two objects when the eyepoint is moved laterally. When parallax appears in a telescope between the image and reticle, this indicates the...

In imaging, the processing of pixel data in such a way that a group of pixels is analyzed at one time rather than one pixel at a time.

Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather than sequentially scanning each source one after another. This approach is...

A mode of data transmission whereby bits of information are carried simultaneously at different frequencies over a single channel.

A pair of waveguides with axes normal to the plane and that guide uniform cylindrical waves.

A device that converts data transmitted in the parallel mode to a sequence of bits at a single frequency for output in the serial mode.

In a camera or cathode-ray tube, distortion that is designated by a lateral skewing of the reproduced image.

Means of amplifying optical waves whereby an intense coherent pump wave is made to interact with a nonlinear optical crystal to produce amplification at two other optical wavelengths. See parametric...

A device using a parametric amplifier inside a resonant optical cavity to generate a frequency-tunable coherent beam of light from an intense laser beam of fixed frequency. This device is tuned by...

Oscillation in rod and disc amplifiers that critically limits the achievable energy storage.

Characteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian optics.

Focus derived from paraxial data.

A ray that behaves according to paraxial equations; one that lies close to and almost parallel to the optical axis.

Description of an optical system in which all the elements are aligned on the same axis.

Having coincident focal points.

One eyepiece of a set having equal distances from their mounting interface to their image plane, permitting freedom to interchange eyepieces without the need to refocus.

Lenses that have identical flange focal distances and can be interchanged.

In data transmission, a self-checking code using a separate bit (the parity bit) to assure that all bytes of transmitted data contain either an odd or an even number of bits. Upon receipt, the data...

Totally coherent radiation is produced by a purely monochromatic point source. In the real world the energy will have a limited bandwidth and the point source will subtend some angle resulting in...

Particle acceleration refers to the process by which charged particles, such as electrons or protons, gain kinetic energy and increase their velocity. This acceleration can occur in various natural...

A whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow that is seeded with micron-sized particles. CCD or CMOS cameras and laser light sheets...

The pressure or stress of one newton per square meter.

An array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by the equation: where represents the wave number in the reciprocal centimeters,...

A mounting used for large concave gratings, whereby the slit, grating and plate holder lie in the Rowland circle, and the photographic plates lie along a large portion of the circle. In this way, a...

Passive optical components are devices or elements used in optical systems that do not require external power or active control to perform their function. These components manipulate light signals...

A passive optical network (PON) is a telecommunications network architecture that uses optical fibers and passive optical components to provide high-speed broadband services to end-users. In a PON...

An LCD that has pixels with no internal drive transistors.

An OLED display formed by creating an array of OLED pixels connected by intersecting anode and cathode conductors arranged in rows and columns. Electrical power is passed through selected pixels by...

The criterion maintaining that if light follows a specific path through an optical system, it will, if reversed, traverse that same path in the opposite direction.

A pathogen is a biological agent, such as a virus, bacterium, fungus, protozoan, or parasite, that causes disease in its host organism. Pathogens have the capability to invade host tissues,...

Pathogenesis refers to the process by which a disease develops and progresses within an organism. It encompasses the sequence of events and mechanisms that lead to the onset, progression, and...

A thin film or coating that forms on various finished surfaces. On optical surfaces it usually denotes aging.

A device that determines the lens shape in the cutting or edging phase of fabrication. It also is used to denote the arrangement of markings on a reticle.

The number of electrons that can share a principal quantum number by preventing identity between any two electrons' four quantum numbers, thereby permitting the periodic arrangement of the elements.