Photonics Dictionary

The tendency to adjust an instrument such as a microscope so that the viewed image appears much closer than infinity.

An instrument providing a continuous measure of color.

Any of the photoelectric and thermal detectors, spectrographs and monochromators, thermographs, scanners, amplifier tubes, snooperscopes and related equipment developed for use with infrared...

Instrumentation designed to permit the perception, recording or measurement of scenes under conditions of low incident illumination.

A family of specialized instruments used by ophthalmologists and optometrists to study a patient's eyes and prescribe spectacles. It includes the ophthalmoscope to observe and photograph the retina;...

A dome-shaped structure used for some optical instruments in place of a flat window. The transparent material should be of good quality and the hemispherical surfaces should be concentric.

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and characteristics of optical components, systems, and devices. These instruments play a...

A traveling microscope or an automatic microdensitometer used to measure the spectrum plate obtained in a spectrograph.

Instruments used for measuring angles and occasionally lengths on the ground. The principal surveying instruments are the level, the stadia telescope, the transit and the theodolite. Laser...

Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering is a method of depositing thin films of material onto a substrate surface...

An instrument that uses optical filtration in order to measure the transmittance for a discrete range or specific number of wavelengths.

An achromat, in the context of optics, refers to a type of lens or lens system designed to reduce chromatic aberration. Chromatic aberration is an optical phenomenon where different colors of light...

A device that measures the intensity of photochemically active radiation, particularly from the sun. One form of this instrument determines the fluorescence initiated by the radiation.

An instrument designed to measure angles in azimuth; used in general topographic work and military gunnery.

A quantitative measure of the amount of radiation given off by an instrument, expressed in roentgens per unit of free air.

An optical tooling instrument consisting of an objective lens, a focusing lens, an optical micrometer, a reticle and an eyepiece. The alignment telescope projects a precise line of sight to which a...

An instrument that reads alphabetic, numerical and special characters by means of a photosensor that measures the varying intensity of the characters reflected from a light source.

The angle between an instrument's line of sight and a reference horizontal plane.

An optical instrument that uses a yellow light of varying intensity with red and blue lights of fixed intensity to test for colorblindness.

An instrument designed to measure the numerical aperture of an objective.

An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and coma. Spherical aberration is an optical aberration that occurs when light rays...

The perceived brightness of an object being viewed at some distance, especially through an optical instrument.

An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical lenses, which have a constant curvature across their surfaces, aspheric lenses...

An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical surface profile. Unlike traditional spherical mirrors, which have a curved...

An instrument that photographs the spectra of an extraterrestrial object.

An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial objects for observation and analysis. It typically consists of two main optical...

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at...

An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials science, and biology. It is a type of scanning probe microscope that...

An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on the principle of autocollimation, where a light source is directed onto a...

Any instrument or system carried by a balloon to the upper atmosphere to measure and record atmospheric information, such as radiation observations, while reducing atmospheric interference.

The range of frequencies over which a particular instrument is designed to function within specified limits. See also fiber bandwidth.

Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It involves measuring and visualizing how the optical power or intensity is...

The angular width of a radiation beam. With respect to a conical beam of light, it is the vertex angle of the cone. The beamwidth is a measure of the rate of divergence or convergence of a light...

An instrument for the detection of the energy distribution of b-particles and secondary electrons.

An instrument designed to produce very hard x-rays by the acceleration of electrons in a varying magnetic field.

Designating any instrument in which both eyes can be used to view the image to achieve a stereoscopic effect, or merely to facilitate observation. See also prism binoculars.

The adjustment of a binocular instrument so that the lines of sight of both telescopes are parallel.

A microscope designed with two eyepieces (oculars), permitting the use of both eyes when viewing through the instrument.

A term pertaining to devices (generally optical) designed for use with both eyes viewing through a single exit pupil. The term may be distinguished from binocular in that biocular instruments contain...

In ophthalmic practice, an instrument that determines the boundaries of the field of view. It is composed of a 2-m square of black velvet with a white spot center at which the patient, 1 m away,...

A ground-based navigation beacon that emits pulsed signals which are picked up by aircraft making an instrument (blind) approach in landing. The signal is transmitted to the aircraft's L-scan...

An instrument used to support optical parts to be cemented, or to be mounted in plaster.

A thermometric instrument used for the detection and measurement of radiant energy. Its essential component is a short narrow strip covered with a dead black absorbing coating and mounted at the...

An instrument that determines, or allows a bombardier to determine, the point in the plane's line of flight at which a bomb must be released to hit a specified target.

An instrument for detecting and analyzing repetitive signals. Using a fixed time delay or "gate," the input signal is sampled numerous times and averaged to increase the ratio of the...