Photonics Dictionary

A glass or metal measurement tool having a precisely calibrated angle between two of its faces.

A sheet of thin brass, one edge of which has been accurately cut to a known and marked circular radius. It is used to check the radius of curvature of a rough-ground lens by contact.

An inspection device in which the profile of a mechanical part is projected onto a ground-glass screen at a precisely known magnification so that the shape of the part can be compared with a scale...

Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of crystalline layers on a substrate material. Epitaxial growth is a critical...

Coating carried out in a sealed chamber evacuated by a mechanical pump in series with an oil diffusion pump to a pressure less than 10-4 mm of mercury, measured by a vacuum gauge. At such a low...

An interferometer spectrometer designed to measure thicknesses of thin films or layers by recording the interferogram and by having a computer within the instrument to establish the distance between...

A machine vision technique that compares a template of the desired image (the correlation kernel) with the actual camera image of an object and generates a new image (the correlation image) that...

A type of radiation detector that depends on the ionization produced in a gas by the passage of a charged particle through it. One of the best known is the Geiger-Müller counter, although cloud...

A dial depth gauge graduated in diopters; a lens measure.

Technique for measuring the volume bulk of materials as they move along a conveyor with an accuracy of better than 1 percent. Based on the use of high-resolution arrays of solid-state detectors, the...

A gauge designed to measure high degrees of vacuum. It consists of a glass bulb attached to the vacuum vessel, the measurement being made by filling the bulb with mercury and observing the volume of...

A device for measuring linear dimensions. The optical caliper generally consists of two circularly mounted mirrors whose angular positions are monitored by an autocollimator, and that are capable of...

Typically used for the examination of manufactured or engineered parts, an optical gauging device, in which a backlight is used to project the silhouette of an object upon a screen in which the...

Optical strain sensors are devices that utilize optical principles to measure the deformation or strain experienced by a material under mechanical stress. These sensors convert changes in strain into...

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.

Photoelastic equipment and supplies refer to instruments and materials used in photoelasticity, a technique used to analyze stress distribution and behavior in materials. photoelastic equipment...

Piezoresistance is a phenomenon in materials science and physics where the electrical resistance of a material changes in response to applied mechanical stress or strain. This change in resistance...

A vacuum gauge designed to measure very high degrees of vacuum by thermal conduction.

A device used to measure the thickness of a given substance.

A gauge designed to measure the degree of vacuum in an evacuated vessel. A simple U-tube containing mercury is adequate for low vacua, but for high vacua other methods must be employed. See McLeod...

A device that calibrates the size, position or distance of objects imaged on a video screen.