Definitions

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.

The wavelength at which a lamp radiates its highest intensity.

The wavelength at which the radiant intensity of a source is maximum.

A prism made up of two air-spaced components. It has the ability to revert, and not invert, an image, and can be used in convergent, divergent and parallel light. May be rotated to compensate for...

Present in photocurrent burst, it is the low frequency pulse that corresponds to the light scattered from the beams in the absence of heterodyne mixing.

In a fiber optic guided missile, the point at which the optical fiber pays out from the bobbin on which it is wound.

Contraction of "picture element." See pixel.

A thin, stretched plastic membrane cemented to a rigid supporting ring. It may be coated to act as a beamsplitter, for example, in a color camera; it is so thin that no perceptible image doubling...

A form of dispersing prism, often used in monochromators, that consists of a common right-angle prism with a 30° dispersing prism attached to each of its square faces. The spectrum formed by the...

A Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses the Peltier effect to transfer heat between two electrical junctions. It can...

See thermoelectric cooling.

In astronomy, the main lobe of an antenna pattern that has a small angular extent in two mutually perpendicular directions. Invisible in space, it would resemble a searchlight beam.

A standard source of high-charge-state ions for accelerators that has an external magnetic field oriented perpendicularly to the two cathode faces. Also called Philips ionization gauge.

A five-sided prism containing two reflecting surfaces at 45° to each other, and two refracting faces perpendicular to the entering and emerging beams. The deviation angle of 90° is...

A pentamirror is an optical component found in SLR cameras, composed of multiple flat mirrors arranged in a pentagonal configuration. Its primary function is to redirect light from the camera lens to...

A pentaprism is a five-sided glass prism used in optical devices, particularly in SLR cameras, to deviate the path of light by 90 degrees and ensure that the image seen through the viewfinder is...

A source of light will not cast a distinct shadow of an interfering, opaque object, but will cast a shadow having two parts: 1. the umbra, or the central, totally dark part of the shadow; and 2. the...

The apparent color, as seen by the human eye, as distinguished from color as a measurable property of light.

A crystalline substance in which all planes are parallel, or approximately parallel.