Photonics Dictionary

A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds, where one femtosecond is equal to 10-15 seconds. These lasers are capable of...

A fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is...

The necessary increase of a photograph's exposure time as the result of the additional absorption of light by the filter being used.

A spectroscopic technique used in the detection of free radicals by virtue of their electronic spectra. In this method, an intense light flash is used to form extensive photolysis and yield a high...

Fluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other electromagnetic radiation. Specifically, fluorescence involves the absorption of...

Fluorescence microscopy is a specialized optical imaging technique used in biology, chemistry, and materials science to visualize and study specimens that exhibit fluorescence. Fluorescence is the...

The suppression of fluorescence by absorption of the stimulating radiation.

The analysis and measurement of the fluorescence emitted by a source. Fluorometric processes are more sensitive than light absorption methods and are rapidly being applied in medical and biological...

A fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external energy source, such as ultraviolet or visible light. The process by which a...

Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced fluorescent molecules. This phenomenon is named after the German scientist...

Observed lengthening in wavelengths of the optical absorption edge of a semiconductor with the application of an electric field.

The dark absorption lines observed in the spectrum of the photosphere of the sun. There are thousands of these lines, the most prominent of which were observed and named by Fraunhofer early in the...

Photoconductivity that may be extended as far as the microwave region because of the absorption of photons by electrons.

FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas sample. It operates based...

Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO2), but they are produced through different manufacturing processes and have distinct properties...

Also known as amplification. 1. The increase in a signal that is transmitted from one point to another through an amplifier. A material that exhibits gain rather than absorption, at certain...

Graphene is a two-dimensional allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice pattern. It is the basic building block of other carbon-based materials...

Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new photons at integer multiples of the frequency of the incoming photons....

A calorimetric calculation from which the temperature vs. time dependence of any point on a sample can be determined, provided surface and bulk absorption, thermal conductivity and heat transfer...

A heat sink for a laser is a device designed to absorb and dissipate the excess heat generated by the laser during operation. This is crucial to maintain the laser's performance, prevent overheating,...

A filter that allows heat radiation from an incident beam to pass without absorption or reflection.

The dip or gap in the profile of a laser beam's line width when it is both homogeneously and inhomogeneously broadened. When an inhomogeneously broadened spectral line is saturated by incident light,...

A thin film of absorbing or nonabsorbing layers in which the absorption of radiation at any point is directly proportional to the electrical field intensity at that point.

In fiber optics, a material whose properties, usually of transmission, are distinctly affected by the absorption of water vapor.

Hyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in certain chemical or biological substances upon undergoing a structural change....

Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the electromagnetic spectrum. Unlike traditional imaging systems that record only a few...

Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a hyperspectral imaging system. In hyperspectral imaging, the electromagnetic spectrum is...

In the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within the material that deviate from its regular or intrinsic composition. These...

Indium phosphide (InP) is a compound semiconductor material composed of indium (In) and phosphorus (P). It belongs to the III-V group of semiconductors, where elements from groups III and V of the...

An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible spectrum of light. These detectors are utilized in various applications,...

A filter exhibiting transparency, absorption or reflectance characteristics specifically for spectral control of wavelengths longer than 700 µm.

An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating infrared (IR) radiation within the infrared spectrum. These lenses are used in...

Used to detect radiation from the infrared region. The functional process includes absorption of infrared radiation, which causes a temperature change, consequently altering the physical properties...

The creation of free electrons within a solid by the absorption of a sufficient amount of photons. The effect produces an increase in the conductivity of the solid.

An absorbing coating medium between fibers, used in some fused fiber optic plates to absorb unwanted light. Such coatings are sometimes called EMA (extramural absorption).

The absorption of a photon raising an electron across the forbidden gap from valence to conduction band of the semiconductor where conductivity is increased and incident radiation may be measured.

Collisional absorption of energy that occurs in inertial confinement fusion systems when hydrodynamic expansion of the plasma causes an electron passing through the field of an ion to absorb...

An atmospheric nonlinear process unique to CO2 laser wavelengths, whereby CO2 absorbs 10.6-µm radiation and the CO2 molecules in the (100) vibrational state are excited to the (001) level, and...

A two-flux theory in which the radiation is assumed to be composed of two oppositely directed radiation fluxes through a continuous medium. The theory has been widely used to relate the total diffuse...

Laser cooling is a technique used to reduce the temperature of a material or a collection of atoms or molecules by using laser light. It is based on the principle of selective absorption and emission...

A natural or mechanical system adversely affected by the influence of laser radiation. During laser damage the common effect of the radiation on the surface of interest is heat accumulation due to...

The study concerned with the stimulation of chemical activity by laser light as a result of the absorption of photons by a molecule. Interaction of laser source with a molecular or atomic species....

A self-healing, index-matching, nonporous coating for optical components that can eliminate production difficulties and deficiencies associated with solid-film contamination and postdeposition...

Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared...

The Lorentz oscillator model is a theoretical model used in physics to describe the response of a charged particle (such as an electron) to an oscillating electric field. It is particularly employed...

Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in temperature. In other words, it is the production and emission of light by a...