It should be noted, however, that the paraxial resolution is quite similar for both electron optical systems.

* ABCD matrix analysis, a type of ray tracing technique used in the design of some optical systems

Makers of optical instruments need to correct optical systems to compensate for aberration.

The elementary theory of optical systems leads to the theorem: Rays of light proceeding from any object point unite in an image point ; and therefore an object space is reproduced in an image space.

The Gaussian theory, however, is only true so long as the angles made by all rays with the optical axis ( the symmetrical axis of the system ) are infinitely small, i. e. with infinitesimal objects, images and lenses ; in practice these conditions are not realized, and the images projected by uncorrected systems are, in general, ill defined and often completely blurred, if the aperture or field of view exceeds certain limits.

Math., 1858 ) and Ernst Abbe showed that the properties of these reproductions, i. e. the relative position and magnitude of the images, are not special properties of optical systems, but necessary consequences of the supposition ( in Abbe ) of the reproduction of all points of a space in image points ( Maxwell assumes a less general hypothesis ), and are independent of the manner in which the reproduction is effected.

* Spectral bands, part of the optical spectra of polyatomic systems

Cold atoms in optical lattices are used as " quantum simulators ", that is, they act as controllable systems that can model behavior of more complicated systems, such as frustrated magnets.

This research at Philips established the technical standard for digital optical recording systems.

Most systems use hybrid fiber coaxial ( HFC ) distribution ; this means the trunklines that carry the signal from the headend to local neighborhoods are optical fiber to provide greater bandwidth and also extra capacity for future expansion.

The electrical telegraph, or more commonly just ' telegraph ', superseded optical semaphore telegraph systems, such as those designed by Claude Chappe for the French military, and Friedrich Clemens Gerke for the Prussian military, thus becoming the first form of electrical telecommunications.

This causes these systems to exhibit unique optical properties, such as Bragg reflection and low-threshold laser emission, and these properties are exploited in a number of optical applications.

* Aberration in optical systems

For real, passive, optical systems, the output luminance is at most equal to the input.

In physics and engineering it is used for analysis of linear time-invariant systems such as electrical circuits, harmonic oscillators, optical devices, and mechanical systems.

* Micro-opto-electromechanical systems, MEMS including optical elements

This subsystem consisted of 4 parts, a Cassegrain telescope with a 1. 05 ° by 1. 05 ° field of view, a shutter and red / green filter assembly with 0. 08s and 0. 20s exposure times, a slow scan vidicon tube which translated the optical image into an electrical video signal, and the electronic systems required to convert the analogue signal into a digital bitstream for transmission.

Only external components such as optical systems, antennas, externally mounted weapons systems or ventilation ports and openings can be damaged, which can make a tank virtually " blind " or allow burning gasoline to seep into the vehicle, forcing the crew to at least open the hatches or perhaps abandon the vehicle.

Quantum optics deals with the application of quantum mechanics to optical systems.

" The mathematical behaviour then becomes linear, allowing optical components and systems to be described by simple matrices.

At the regional cable television headend | headend, the TV channels are sent multiplexed on a light beam which travels through optical fiber trunklines, which fan out from distribution hubs to optical nodes in local communities.

At the optical node, the light beam from the fiber is translated back to an electrical signal and carried by coaxial cable distribution lines on utility poles, from which cables branch out to subscriber residences.

Alternatively, the image can be photographically recorded by exposing a photographic film or plate directly to the electron beam, or a high-resolution phosphor may be coupled by means of a lens optical system or a fibre optic light-guide to the sensor of a CCD ( charge-coupled device ) camera.

Most optical keyboards require at least 2 beams ( most commonly a vertical beam and a horizontal beam ) to determine the actuated key.

Some optical keyboards use a special key structure that blocks the light in a certain pattern, allowing only one beam per row of keys ( most commonly a horizontal beam ).

The mechanism of the optical keyboard is very simple – a light beam is sent from the emitter to the receiving sensor, and the actuated key blocks, reflects, refracts or otherwise interacts with the beam, resulting in an identified key.

The specialist Datahand keyboard uses optical technology to sense keypresses with a single light beam and sensor per key.

The beam in the cavity and the output beam of the laser, when travelling in free space ( or a homogenous medium ) rather than waveguides ( as in an optical fiber laser ), can be approximated as a Gaussian beam in most lasers ; such beams exhibit the minimum divergence for a given diameter.

It is possible, using nonlinear optical processes, to exactly reverse the propagation direction and phase variation of a beam of light.

The reversed beam is called a conjugate beam, and thus the technique is known as optical phase conjugation ( also called time reversal, wavefront reversal and retroreflection ).

The optical depth expresses the quantity of light removed from a beam by scattering or absorption during its path through a medium.

Beam diameter is usually used to characterize electromagnetic beams in the optical regime, and occasionally in the microwave regime, that is, cases in which the aperture from which the beam emerges is very large with respect to the wavelength.

The beam divergence of an electromagnetic beam is an angular measure of the increase in beam diameter or radius with distance from the optical aperture or antenna aperture from which the electromagnetic beam emerges.

Beam divergence is often used to characterize electromagnetic beams in the optical regime, for cases in which the aperture from which the beam emerges is very large with respect to the wavelength.

Examples of optical beam steering approaches include mechanical mirror-based gimbals or beam-director units, galvanometer mechanisms that rotate mirrors, Risley prisms, phased-array optics, and microelectromechanical systems ( MEMS ) using micro-mirrors.

Current business products focus on server & embedded speech recognition, telephone call steering systems, automated telephone directory services, medical transcription software & systems, optical character recognition software, and desktop imaging software.

Flatness may now monopolize everything, but it is a flatness become so ambiguous and expanded as to turn into illusion itself -- at least an optical if not, properly speaking, a pictorial illusion.

These tubes may differ both in the choice of the electron optical system and in the design of the coupling members.

The electron optical system may be either a magnetic or electrostatic one.

Development of the optical system is highly dependent on the presence of melanin, and the reduction or absence of this pigment in albinistic individuals may lead to

Rough simulations of optical properties may be additionally employed: a simple calculation of the ray from the object to the point of view is made.

From pictures on the wall to movies to television to video games to computers, each successive generation has been exposed to richer optical displays than the one before and may have become more adept at visual analysis.

Surface treatments, coatings or lamination may follow to improve the chemical durability ( glass container coatings, glass container internal treatment ), strength ( toughened glass, bulletproof glass, windshields ), or optical properties ( insulated glazing, anti-reflective coating ).

Other optical devices, such as spinning mirrors, modulators, filters, and absorbers, may be placed within the optical resonator to produce a variety of effects on the laser output, such as altering the wavelength of operation or the production of pulses of laser light.

An LED is often small in area ( less than 1 mm < sup > 2 </ sup >), and integrated optical components may be used to shape its radiation pattern.

They are usually shaped to fit in a roughly oval, not circular, frame ; the optical centers are placed over the eyeballs ; their curvature may not be axially symmetric to correct for astigmatism.

One recent mathematical modeling study has suggested that the optical properties of the cristae in filamentous mitochondria may affect the generation and propagation of light within the tissue.

Buttons, sliders, and knobs are the most common controllers provided, but rotary encoders, transport controls, joysticks, ribbon controllers, vector touchpads in the style of Korg's Kaoss pad, and optical controllers such as Roland's D-Beam may also be present.

As the material collapses under its own weight, massive stars may form in the center, and their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths.

* Quantum oscillator may refer to an optical local oscillator, as well as to a usual model in quantum optics.

Open Skies aircraft may have video, optical panoramic and framing cameras for daylight photography, infra-red line scanners for a day / night capability, and synthetic aperture radar for a day / night all weather capability.

In particular, the pump band may consist of several distinct energy levels, or a continuum of levels, which allow optical pumping of the medium over a wide range of wavelengths.

While refraction allows for phenomena such as rainbows, it may also produce peculiar optical phenomena, such as mirages and Fata Morgana.

A rare optical phenomenon may occur shortly after sunset or before sunrise, known as a green flash.

Function is the optical Lagrangian from which the Lagrangian and Hamiltonian ( as in Hamiltonian mechanics ) formulations of geometrical optics may be derived.

On meters that allow interfacing with computers, optical isolation may protect attached equipment against high voltage in the measured circuit.

The waveguide may be dielectric ( an optical fiber ) or metallic.

An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed.