Optical depth, or optical thickness, is a measure of transparency.

Optical transparency in polycrystalline materials is limited by the amount of light which is scattered by their microstructural features.

In addition, Side looking radars, High-powered Optical Satellites, and sky-scanning, high-Aperature, high sensitivity Radars such as Radio telescopes, would all be able to narrow down the location of a Stealth aircraft under certain parameters.

* Optical ring resonators

* Optical ring resonators

Optical ring, cylindrical, and spherical resonators have also been proven useful in the field of biosensing.

* Optical aberration, an imperfection in image formation by an optical system

This phenomenon, known as gravity darkening or the von Zeipel effect, was confirmed for Altair by measurements made by the Navy Prototype Optical Interferometer in 2001, and analyzed by Ohishi et al.

This includes the Optical Microscope, Transmission Electron Microscope, Scanning Electron Microscope, Fluorescence Microscope, and by Confocal Microscopy.

Optical technology, such as the telescope, sextant and other devices that use telescopes, allowed for accurate surveying of land and the ability of mapmakers and navigators to find their latitude by measuring angles to the North Star at night or the sun at noon.

* Masters of Deception: Escher, Dali & the Artists of Optical Illusion 2004 by Al Seckel.

Optical keyboard technology was introduced in 1962 by Harley E. Kelchner for use in a typewriter machine with the purpose of reducing the noise generating by actuating the typewriter keys.

The observatory is administered by the National Optical Astronomy Observatory ( NOAO ).

** Self-focusing, an effect due to the Optical Kerr effect ( and possibly higher order nonlinearities ) caused by the spatial variation in the intensity creating a spatial variation in the refractive index

** Self-phase modulation ( SPM ), an effect due to the Optical Kerr effect ( and possibly higher order nonlinearities ) caused by the temporal variation in the intensity creating a temporal variation in the refractive index

Optical theory progressed in the mid-17th century with treatises written by philosopher René Descartes, which explained a variety of optical phenomena including reflection and refraction by assuming that light was emitted by objects which produced it.

Optical cards were produced by Landis + Gyr and Sodeco from Switzerland and were popular early phonecards in many countries with first optical phonecards successfully introduced in 1977 in Belgium.

* Optical lattices ( qubit implemented by internal states of neutral atoms trapped in an optical lattice )

* A step by step tutorial on Optical Rotation

*" Microscope Objectives: Numerical Aperture and Resolution " by Mortimer Abramowitz and Michael W. Davidson, Molecular Expressions: Optical Microscopy Primer ( website ), Florida State University, April 22, 2004.

This image merges data acquired by Swift's Ultraviolet / Optical Telescope ( blue and green ) and X-Ray Telescope ( red ).

* Optical Camouflage by the Tachi Lab in Japan

* Long-distance Atmospheric Optical Communications, by Chris Long and Mike Groth ( VK7MJ )

* Optical illusions and visual phenomena by Michael Bach

; Optical tablets: Optical tablets operate by a very small digital camera in the stylus, and then doing pattern matching on the image of the paper.

* Optical glass construction

Optical microscopes have refractive glass and occasionally of plastic or quartz, to focus light into the eye or another light detector.

Optical coatings, protective and decorative coatings, and electro-optic components can be applied to glass, metal and other types of substrates with these methods.

Cross-section view of SLR system: 1: Front-mount lens ( four-element Tessar design ) 2: Reflex mirror at 45-degree angle 3: Focal plane shutter 4: Film or sensor 5: Focusing screen 6: Condenser lens 7: Optical glass pentaprism ( or pentamirror ) 8: Eyepiece ( can have diopter correction ability )

Optical corner reflectors, called corner cubes, made of three-sided glass prisms, are used in surveying and laser rangefinding.

* Optical fiber # Preform, a piece of glass used to draw an optical fiber

* IEC 60958 Type II Optical – optical fiber, usually plastic but occasionally glass, with an F05 connector, also used in consumer audio ( optical S / PDIF )

Optical diagram showing light being refracted by a spherical glass container full of water, from Roger Bacon, De multiplicatione specierum.

Optical filters are devices that selectively transmit light of different wavelengths, usually implemented as plane glass or plastic devices in the optical path which are either dyed in the mass or have interference coatings.

Optical diagram showing light being refracted by a spherical glass container full of water.

* Open joint stock company " Vologda Optical and Mechanical Plant " — produces optical devices ;

* 1953: Todd-AO formed as a joint venture of Mike Todd and the American Optical Company for the purpose of developing and distributing a large film format presentation system incorporating a wide, curved screen with multi-channel sound.

Stores are divided into four types: Optical Lab, Superstores, Franchises ( owned entirely by the proprietor but under licence to use the Vision Express name and with some access to Grand Vision services ) and joint venture partnerships ( owned on a 50: 50 basis by a manager / proprietor and the Vision Express subsidiary, Abbeyfield V. E.

The HOT ( Haut subsonique Optiquement Téléguidé Tiré d ' un Tube, or High Subsonic Optical Remote-Guided, Tube-Launched ) is a second-generation long-range anti-tank missile system developed originally as an effort to meet a joint German-French Army requirement, by the then German firm Bolkow and the French firm Nord, to replace the older SS. 11 wire guided missile which was in service with both nations.

Optical infinity — This was achieved by adjusting the focal distance so that it was above what is sometimes referred to as " optical infinity ", which is generally taken as about 30 ft or nine m. In this context, " Optical Infinity " is the distance at which, for the average adult person, the angle of view of an object at that distance is effectively the same for both the left and right eyes.

Optical images reveal clouds of gas and dust in the Orion Nebula ; an infrared image ( right ) reveals the new stars shining within.

The stereo information is carried on stereo sources such as VHS TV, DVD's, 35mm Theatrical Print Optical Soundtrack, Television Broadcasts from which the surround information can be decoded by a processor to recreate the original Dolby Surround ( left, center, right, sub and surround ) mix.