Photonics Dictionary

The eye's involuntary reaction in the process of accommodation. This reflex is most dramatic in response to looking at a distant object after having previously been focused on a near object or vice...

The prism used in a rangefinder to bend the lines of sight through the instruments into the eyepieces.

That surface of a lens located nearest to the eye.

An electro-optical infrared tracker consisting of a beamsplitter, an illuminating source, an image dissector tube and an electronics unit, that automatically acquires and tracks particular eye...

A monolithic device containing both photonic and electronic sources, detectors, modulators, etc., on a single semiconductor substrate.

A lenticular screen having the lenticules tipped about 20° to compensate for off-normal projection.

Focus derived from paraxial data.

The focusing of an electron beam by a magnetic field that permanently retains the majority of its magnetic properties.

The current that flows through a photosensitive device, such as a photodiode, as the result of exposure to radiant power.

The electron stream emitted by a phototube when the cathode is exposed to light.

A prism used in a photometer for the adjacent comparison of separate luminance.

A photonic integrated circuit (PIC) is a compact and integrated device that incorporates multiple photonic components and functions on a single chip, similar to the way electronic integrated circuits...

An aberration of a lens system caused by an increase in lens focal length as the field angle increases. The amount of distortion normally increases as the cube of the image height.

Locus of points on a chromaticity diagram that includes the chromaticities of blackbody radiators.

A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a generator to produce electricity.

A pair of telescopes with prismatically erected images, mounted side by side with the eyepieces at the interocular distance of the observer. This separation is adjustable with a convenient millimeter...

A planar photocathode and a planar phosphor screen mounted in a close-spaced parallel configuration in an evacuated enclosure so that the ensemble of photoelectrons emitted from each photocathode...

In the dye laser, the molecule that takes out energy from the triplet state during collisions between the dye and quencher to achieve long-pulse emission.

A type of internal focusing in which only the lens elements closest to the rear of the lens barrel are moved.

The formation of a distinct, irregular surface pattern on a photographic emulsion due to differential swelling of the gelatin.

Also known as reversed telephoto lens. A lens consisting of an ordinary objective with a negative component near its front focal point. Thus, the back focus is large, relative to its focal length....

A term describing a type of scratch.

A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example, to reduce noise as in correlated double sampling.

The process of grinding the convex surface of a convexo-concave meniscus.

A projection screen having vertical ribs or flutes set into a plastic surface.

Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the diffraction limit of traditional optical microscopes, allowing for the...

Single-molecule Förster resonance energy transfer (smFRET) is a specialized technique in biophysics and molecular biology used to study the distances and dynamic interactions between two...

An advanced technique that allows the detection of one molecule within a crystal or a cell through optical excitation. Single-molecule spectroscopy (SMS) can image at subwavelength scales, down to a...

A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing process to precisely cut and slice materials such as crystals, glass, and quartz...

A filter that creates spherical aberration resulting in an image with a soft outline.

A lens that exhibits spherical aberration when used at large aperture settings, and that forms an image with a slightly blurred outline.

Measurement of absorption by the gas of interest in the 2- to 6-µm range as a function of tangent height pressure. The pressure profile may be inferred by using CO2 absorption profile...

On a chromaticity diagram, the line on which fall the chromaticities of the pure spectrum colors.

Pertaining to the manner in which light is reflected, as by a mirror or speculum.

A reflector that exhibits specular reflectance, producing a direct image of its source. Also known as regular reflectance.

See regular transmittance; the term specular is not properly applied to transmission.

A feature in the chromosphere of the sun formed by a jet of gas that reaches from the chromosphere into the corona and has the appearance of a brightly luminous spike.

The ability to perceive binocularly the apparent depth and relative distance of objects.

A device used to detect elevation, pyramid and resolution errors in prisms and other components by bringing them into contact with the three highly polished, flat, perpendicular surfaces that form...

A microcircuit whose passive components consist of a ceramic-metal combination deposited on a given substrate by screening and firing processes.

A circuit whose passive components are deposited on a given substrate by sputtering or vacuum processes.

The minimum driving current corresponding to lasing threshold at a specified temperature. (Ith).

Measurement of a translation stage's deviation from absolute straightness, that is, its angular motion in both the vertical and the horizontal planes.

Twisted intramolecular charge transfer (TICT) is a phenomenon observed in certain organic molecules containing electron-donor and electron-acceptor groups that are linked together within the same...

A pulsed laser having molecular nitrogen as laser material and a wavelength output of 337 nm in the ultraviolet region. It is essentially a channel flashtube in which a pulse is applied to the...