Photonics Dictionary

Characteristic of an acousto-optic modulator, defined by the overlap integral of the incident light and sound field profiles; similar to a convolution operator.

Two-photon excited fluorescence (TPEF) is a nonlinear optical method that allows imaging of biological cells and living tissue. The advantage of TPEF in comparison to conventional fluorescence...

This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and requiring a high spatial and temporal concentration of photons. The ensuing...

Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It involves using a focused laser to polymerize a photosensitive material in a...

Referring to compound semiconductor materials combining one element with two valence electrons and one or more with six. Examples include beryllium oxide and zinc selenide. (II-VI).

A testing device that provides a contour map of the emergent wavefront for the observer in terms of the given wavelength of the light.

Twyman-Green interferometry is a technique used in optics to measure the flatness or surface profile of optical components with high precision. It is based on the principles of interference of light...

The form taken by scattered light, as a result of the Tyndall effect.

The effect by which sufficiently small particles will scatter blue light at right angles to the incident beam. This scattered light is completely linearly polarized.

A set of samples used in the analysis of multielement thin films.

An ultrafast pulsed laser is a type of laser that emits extremely short pulses of light with durations typically on the order of femtoseconds (10-15 seconds) or picoseconds (10-12 seconds). These...

A form of microfiche that has an information reduction ratio that is greater than 100 to 1.

The frequency band from 300 to 3000 MHz. The corresponding wavelengths are from 10 to 100 cm.

Photographic recording of rapid events at a rate exceeding 106 frames per second.

A system used to measure very small displacement by electrical means.

The process of microphotography that involves the reduction of the original at a ratio greater than 100 to 1. The process is usually accomplished by the use of a reduced-scale negative, which, in...

A dark-field microscope used to view extremely small objects. These objects are suspended in a gas or liquid in an enclosure having a black background. A convergent pencil of bright light enters from...

The rays (such as ultraviolet rays) lying past the visible region of the spectrum.

A highly accurate cathode-ray tube used to display information with the utmost efficient stability and resolution. The information is viewed as a series of points, particularly suited for...

A laser capable of generating light pulses that last only a few femtoseconds. This can be achieved by nonlinear filtering to increase bandwidth and compress the pulse or by passive mode-locking or...

A device that uses a piezoelectric crystal to convert ultrasonic sound waves, transmitted through a subject, into a voltage that modulates the electron beam of a cathode-ray tube.

Ultrasound used in the cleaning of metal and optical parts by virtue of its vibration rates. Large acoustic forces break off particles and contaminants from surfaces.

A two- or three-dimensional space grating formed when ultrasonic beams with varied paths of propagation intersect.

A mechanical, electrical, thermal or optical detector designed to identify and measure ultrasonic radiation.

The space between diffracting centers of an ultrasonic wave that is forming certain light diffraction spectra.

The formation and display of three-dimensional images by ultrasonic energy. In one technique, the energy pulses from an ultrasonic transducer scan the object through a liquid medium and, receiving...

The optical diffraction spectra formed, or the method that produces them, when a light beam is transmitted through a longitudinal sound field.

An instrument with a fluid that modulates a light beam traversing it because of the effect of ultrasonic waves passing through the fluid.

A light-interference device whose excitation is determined by the modulation of a light beam by an ultrasonic field.

Ultrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above 20,000 Hz. These waves are termed ultrasonic because they are beyond the range...

The region of the electromagnetic spectrum from 320 to 400 nm.

A filter that is opaque from 200 to 400 nm.

The region of the electromagnetic spectrum from 280 to 320 nm.

Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible light. UV-C radiation spans the electromagnetic spectrum with wavelengths...

Ultraviolet (UV) coatings are specialized optical coatings designed to operate in the ultraviolet region of the electromagnetic spectrum, typically ranging from 10 nm to 400 nm. These coatings are...

A technique, involving spectrophotometry in the ultraviolet, that is designed to determine the colors of thin-layer chromatographic absorbents after elution.

Ultraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet light, which is electromagnetic radiation with wavelengths shorter than...

A type of lamp that emits a high quantity of ultraviolet radiation. This may be an arc lamp encased in a bulb of a glass that is transparent to ultraviolet rays.

A lens intended for use with wavelengths shorter than about 380 nm. It must be made of quartz, calcium fluoride, lithium fluoride or some other material transparent to ultraviolet radiation, as glass...

A microscope used either to detect selective absorption of various wavelengths by the specimen or to achieve increased resolution by virtue of the short wavelength of ultraviolet radiation. Electron...

The study and photographing of microscope specimens in ultraviolet light; using an optical microscope containing fluorite and quartz components to efficiently image wavelengths much shorter than the...

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...

A technique for measuring the energy spectrum of electrons emitted during the absorption of ultraviolet radiation. This spectrum reveals the characteristic ionization energies of the molecules and...

The photographic recording that uses ultraviolet radiation to irradiate the microscope sample being examined and to form an image of the object on a photographic medium. The components of the...

Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is electromagnetic radiation with wavelengths shorter than those of visible light,...

A spectrophotometer designed for use in the 200- to 380-nm range of the electromagnetic spectrum and equipped with a calibrated scale to determine wavelength.