Photonics Dictionary

The logarithmic method of determining emulsion speeds developed by the German standards organization, Deutscher Normenausschuss, in which the speed of the emulsion is doubled for each increase of...

A direct reading spectrograph having a photomultiplier assembly in place of a photographic plate. The output from the photomultiplier assembly is received by a microammeter or a pen recorder.

1. That action occurring when light passes through an optical interface at other than normal incidence, i.e., refraction. 2. The curving of a path of light that passes close by a massive object, due...

An imaging technique that labels all gray pixels as either black or white before processing begins.

Focal, nodal or principal points of a lens. If the respective distances of the object and image are measured from the cardinal points, all thin-lens equations are applicable to thick lenses.

Proportions of standard primaries (tristimulus values) required for a color match; ratios of each tristimulus value of a color to their sum. In the CIE colorimetric system, designated X, Y and Z.

The low-refractive-index material that surrounds the core of an optical fiber to contain core light while protecting against surface contaminant scattering. In all-glass fibers, the cladding is...

In fiber optics, the glass that is found around the glass core of the fiber, and that has a lower refractive index than the fiber.

A mode that is confined by virtue of a lower-index medium surrounding the cladding. Cladding modes, in the terminology of mode descriptors, are equivalent to cladding rays in the terminology of...

A mechanism or device, especially a coating with a refractive index equal to or slightly greater than that of an optical fiber's cladding, that removes modes propagating through the cladding by...

A ray that is reflected into the core of an optical fiber from the outer surface of the cladding.

A method of improving the signal-to-noise ratio of an interferogram by adding another interferogram to it.

A ring dye laser that uses prisms and a saturable absorber within the laser cavity to shape and shorten the pulses generated. Counterpropagating modes oscillating simultaneously in the ring...

A deliberately nonlinear amplitude modulation that strengthens weak signals and reduces strong signals for transmission.

A method of producing large volumes of plastic optical components in which powdered or sheet plastic is pressed between heated dies.

Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision machining tools to remove material from a workpiece. In CNC grinding, a...

A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed by the material through conduction and melts the material to produce an edge...

An instrument used to measure the coordinates of a point on an object such as a photographic plate.

An optical fiber, usually a single-mode fiber, that has an outer cladding with nearly the same index of refraction as the core and an inner cladding with a very low index of refraction.

Die bonding is a critical process in semiconductor manufacturing and microelectronics assembly, where a semiconductor die or chip is attached and electrically connected to a substrate or a package....

The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials. A direct recording method involves the passage of the recording medium...

A term applied to the recording of video images by means of magnetic tape or disc, so that the image's record can be played back in a video format at a later time.

A technique that uses the passage of an electrical current through a recording medium to produce a permanent image on that medium.

A ray that has a nonisotropic speed in a doubly refracting crystal. It does not necessarily obey Snell's law upon refraction at the crystal surface.

A method used to produce precision spherical and aspheric molded glass lenses without grinding or polishing.

A material that surrounds a fiber optic cable's buffer tubes to prevent moisture from entering if the jacket is breached.

The process in the manufacture of an optical system that gives it the required geometric shape.

Machinery used to grind and finish a component, such as a lens or prism, to a desired precision. Usually such machines carry a cup-shaped or flat tool (lap) into close contact with the part. An...

A tool of cast iron or another suitable medium used with a slurry of silicon carbide, aluminum oxide or emery for grinding optical surfaces.

Also known as constant angle or constant deviation fringes. The interference fringes observed with dense flat plates near normal incidence. The fringes of the Fabry-Perot interferometer are Haidinger...

The total fusion and sealing of materials, or usually an enclosure, to ensure that they are airtight.

That part of the cladding wherein the refractive index is constant within a specified tolerance, as a function of radius.

A single housing that includes means of recording an image photographically and electronically.

A thermoplastic or thermosetting material used to hold an object fixed and keep it from deterioration. In microcircuitry, the process of imbedding is known as potting.

A method of producing high-quality plastic optics in large volumes by injecting the heated, liquified plastic at high pressure into a tooled mold with polished chromium stainless steel inserts to...

The use of a small ultrastable master oscillator (a diode-pumped Nd:YAG laser) to achieve single-frequency operation of a large pulsed Nd:YAG host laser, providing improved bandwidth and temporal...

A development aimed at extending the life of a tungsten filament. The iodine vapor in the lamp envelope combines with the tungsten vapor emitted by the hot filament, but the compound is decomposed by...

The process of binding or attaching larger metal sheets by laser welding. The effect is generated by higher power densities which, while creating a larger weld, produce a vapor that is penetrated by...

In a sequence of laser pulse emissions, the intitial pulse that often helps initiate a reaction at the target surface, whereas the trailing edge maintains the reaction.

The production of rough glass lens blanks that are pressed while red-hot to the approximate size and shape of the finished lens, ready for fine grinding and polishing. Large companies often do their...

A type of recording in which the recording line remains fixed and the recording medium is fed past the recording device.

Pockels cell or dynamic optical retarder in which the electrical field is applied in a direction parallel to that of light passing through it.

A waveform that can oscillate along the length of the laser cavity.

A dye laser cell configuration in which the dye flows in the direction of the axis of the laser, yielding symmetrical energy distribution but small repetition rates.

In optical fiber, bends that are larger than microbends (see microbending), being visible. Generally they are caused by bending the cable beyond the specified bend radius. Light escaping at the bends...

In optical fiber, sharp but microscopic curvatures that create local axial displacements of a few microns and spatial wavelength displacements of a few millimeters. One frequent cause is longitudinal...