Photonics Dictionary

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...

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...

Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of thermophotovoltaics. In a thermophotovoltaic system, thermal radiation from a heat...

The scattering of electromagnetic waves by free electrons, whereby the incident radiation and the scattered radiation are of the same wavelength.

Three-photon microscopy is an advanced imaging technique that belongs to the family of multi-photon microscopy methods. It is used in biological and medical research to capture high-resolution images...

A Ti:sapphire laser is a type of solid-state laser that utilizes a titanium-doped sapphire crystal as the gain medium. The name Ti:sapphire comes from the combination of titanium (Ti) as the dopant...

A restricting wavelength above or below which a specified form of radiation is totally almost absorbed by a specified medium.

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet that uses an electrical discharge transverse to (across) the optical axis to...

Computation of tristimulus values by integrating or summing, over the visible wavelength region, the product of the relative spectral power of a CIE standard source, the reflectance of the object...

Any form of laser; e.g., a dye laser, having an output that can be adjusted over a wide range of wavelengths. Normally the range is about 70 nm wide.

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

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...

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

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...

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) 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 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...

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.

That invisible region of the spectrum just beyond the violet end of the visible region. Wavelengths range from 1 to 400 nm.

Also known as UV-VIS spectrometer, a device that measures the absorbance, reflectance or transmittance of light in the ultraviolet or visible wavelengths absorbed, reflected or transmitted. Commonly...

A multilayer antireflective thin-film coating, so called because its reflectance rises steeply at wavelengths above and below a narrow band at zero. The v-coat is particularly useful in high-power...

The technique of producing spectrograms in wavelengths beyond 120 nm by the use of a diffraction grating and a Schumann plate in a vacuum environment.

Radiation whose spectrum runs between 100 and 300 nm. Any work with these wavelengths requires evacuated equipment.

Any source that emits radiation of wavelengths between 100 and 300 nm. Instruments used to study these sources must be evacuated, as vacuum ultraviolet does not travel freely in air.

A method of spectral analysis using wavelengths between 100 and 300 nm that utilizes both emission and absorption techniques.

The frequency band from 30 to 300 MHz. The corresponding wavelengths are from 1 to 10 m. (VHF).

The frequency band from 3 to 30 kHz. The corresponding wavelengths are from 10 to 100 km. (VLF).

That region of the electromagnetic spectrum to which the retina is sensitive and by which the eye sees. It extends from about 400 to 750 nm in wavelength.

Volume Bragg gratings (VBGs) are specialized optical elements that consist of periodic variations in refractive index throughout the volume of a transparent material, typically a photosensitive glass...

The frequency of a wave divided by its velocity of propagation; the reciprocal of the wavelength.

Also referred to as physical optics - the area of optics in which the wave nature of light is essential when defining its propagation. To exploit the wave phenomena of light, one must interact light...

For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted by virtue of the dependence of the phase and group velocities on...

Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or sound waves, are trapped and circulate along the periphery of a curved...

Wide-field fluorescence microscopy uses either naturally occurring structures or staining with fluorescent tags that are activated by specific wavelengths of light and then emits a different...

The formula that gives the wavelength of maximum spectral radiant emittance of a perfect blackbody: λmax = 2898/T(µm) The radiation at this λmax can be calculated as follows:...