Photonics Dictionary

Waves that propagate along the interface between two different media without radiation with exponentially decaying evanescent fields on both sides.

The specification of allowable flaws in a surface by comparison to reference standards of quality. Two graded sets of surface quality standards are employed. The first denotes defects of a long...

The standards of MIL-O-13830 set by the US government relative to tolerable surface scratches and other such defects in an optical system. A series of standard glass plates that have been...

A term that describes both the color and intensity of the immediate environment of the object or image being viewed.

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...

A small telescope mounted on a tripod and free to rotate about a vertical axis. A spirit level is mounted over the telescope and adjusted so that when the bubble is central, the telescope axis is...

Swept-source optical coherence tomography is an imaging technique used in medical diagnostics, particularly in ophthalmology, to visualize and analyze the internal structures of biological tissues,...

The length of the oscillation of a grinding or polishing lap.

Abbreviation of "synchronization.'' In television, the timing signals used to drive the scanning process. Horizontal sync triggers the retracing of the raster line beginning at the left-hand...

A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or positrons, in a closed, circular or elliptical path. The name synchrotron...

An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially recorded on a photographic film as a hologram. If the interference field...

The equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the same central illumination as the lens being considered: where...

The series of interference bands that appear in the spectrum when a specified glass plate is inserted into a spectroscope, from the side of the blue portion of the spectrum, so that the plate...

The law stating that the brightness of an object that is examined through a slotted disc, rotating over a critical frequency, is proportional to the angular aperture divided by the opaque sectors.

1. The anode or anticathode of an x-ray tube that emits x-rays when bombarded by electrons. 2. The screen in a television imaging tube that is scanned by an electron beam to determine the...

1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain, temperature or pressure, and transmit this data to a receiving station. 2. A...

The science of sensing and measuring information at some remote location and transmitting the data to a convenient location for reading or recording.

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

A television display system in which the television signal is converted to an image that is projected onto either a front or rear projection screen.

The combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene and sound in a television picture.

The graph of the oscillating variations composing the wave of a video signal.

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

An electron tube that has an anode, a cathode, a control electrode and another electrode (usually a screen grid).

A precise telescope set on a pair of rotation axes, the horizontal and vertical axes equipped with two divided circles. One circle measures horizontal angles and the other measures vertical angles....

The process of producing a visible two-dimensional image of a scene that is dependent on differences in thermal or infrared radiation from the scene reaching the aperture of the imaging device.

Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces in contact. These materials are primarily employed in electronic devices,...

Also known as analog thermogram. The resultant photograph, illustrating, in tones ranging from black to white, the spatial relationship of the infrared radiation temperatures of the different details...

The instrument used to collect thermal radiation information on an object by scanning. It consists basically of a detector, a photoconductive element that converts incident radiation to an electrical...

Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera, to detect and visualize the infrared radiation emitted by objects. This...

An adhesive whose viscosity decreases as the temperature is increased to a limit. Canada balsam, resin and pitch are examples of thermoplastic cements.

A display device having a thermoplastic film as the control layer medium. The film, moving from a playoff reel, is scanned by an electron gun and melted by an RF heating unit. Deformation of the film...

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

Successive layering of resistive, dielectric and conductive inks on a substrate by a type of screening process.

Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical, electrical, or mechanical properties. These coatings are composed of thin...

Thin-film deposition equipment refers to machinery and tools used in the process of depositing thin layers of material onto a substrate surface. This technique is commonly employed in various...

A laser having a material, such as ruby, that has an energy state structure of three levels: the ground state (1) wherein excitation applied to the material raises ions in the material into the...

In laser damage testing, the exposure of many sites of a sample to different intensities of laser irradiation to discover the point at which the laser induces failure of the material.

An arc discharge tube having a grid that is used to start the discharge through an atmosphere of inert gas or vapor at low pressure.