Photonics Dictionary

An abridged spectrophotometer refers to a simplified or compact version of a traditional spectrophotometer, which is a scientific instrument used to measure the intensity of light at different...

Absolute white is a term used in color science and imaging to describe a reference white point that represents the brightest, most neutral white achievable. It serves as a standard for measuring and...

Absorption spectroscopy is a fundamental analytical technique used to study the interaction between electromagnetic radiation and matter. It involves measuring the absorption of light by a sample...

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...

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...

A piece of glass polished flat on one side, with a pair of polished faces that form an angle close to 180° on the other side, the dividing edge running down the middle of the plate. It is used...

Diffuse reflectance spectroscopy (DRS) is a nondestructive analytical technique used to investigate the optical properties of materials, particularly in the field of spectroscopy. Unlike traditional...

A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It consists of a periodic modulation of the refractive index along the length...

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...

A Fizeau interferometer is an interferometric device that uses the principle of interference to measure the surface flatness and quality of optical components. It consists of a light source,...

Fluorescence and phosphorescence spectroscopy are techniques used to study the emission of light (photons) by molecules following their excitation by external energy sources. While both processes...

Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of fluorescence emissions from fluorophores within a sample. Unlike traditional...

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin concentration in the brain. It utilizes near-infrared light to penetrate the...

The term half bandwidth (HBW) generally refers to the width of a spectral band or frequency range at half of its maximum amplitude. It is commonly used in the context of signal processing, optics,...

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....

Indirect time-of-flight (iTOF) is a method used in 3D imaging and depth sensing to measure the distance to an object based on the time delay between the emission of a light pulse and the detection of...

An infrared light-emitting diode (IR LED) is a semiconductor device that emits infrared light when an electric current passes through it. Similar to standard LEDs that emit visible light, IR LEDs are...

The method that, by measuring the absorption along an atmospheric path at wavelengths ranging from two to a continuum, can determine pollution concentrations of gases.

A means of testing optical fiber for macrobending losses by wrapping the fiber once at very low tension around a mandrel, and then measuring attenuation vs. wavelength.

An optical channel monitor (OCM) is a device used in optical communication systems to monitor and analyze the performance of individual channels within a wavelength-division multiplexing (WDM)...

An optical frequency comb is a tool used for measuring frequencies with extremely high precision. It is essentially a spectrum consisting of a series of discrete, equally spaced frequency lines, much...

Optical strain sensors are devices that utilize optical principles to measure the deformation or strain experienced by a material under mechanical stress. These sensors convert changes in strain into...

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 device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a photocell. Slow counting rates can be recorded by a mechanical counter, but...

A technique proposed for studying the atomic structure of crystals by measuring the interference pattern generated when the crystal is illuminated by a burst of finely tuned x-rays. The resulting...

Photon flux refers to the rate at which photons (particles of light) pass through a unit area per unit time. It is a measure of the intensity or brightness of light in a specific region of space or...

A method of measuring complex sequential photosynthetic reactions by varying the pulse time and wavelength of light generated by a combination of argon-ion and dye lasers.

A quantum cascade laser (QCL) is a type of semiconductor laser that operates based on the principles of quantum mechanics. It is a versatile and powerful device used for emitting coherent light in...

Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other low-frequency modes in a system. Named after the Indian physicist Sir C.V. Raman...

Reflectance spectroscopy is a technique used to analyze the reflective properties of materials across various wavelengths of the electromagnetic spectrum. By measuring the reflectance of light from a...

A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector specifically designed for detecting and measuring light intensity. Silicon...

Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or instances. It is a measure of how well a measurement instrument or system can...

A spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the electromagnetic spectrum, typically in the visible and ultraviolet regions. It is...

In a general sense, any one of a class of instruments used to disperse radiation, visible or invisible, into its component wavelengths and for determining or measuring the resultant spectrum. In a...

Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves measuring and analyzing how different materials absorb, emit, or scatter light,...

swept-source Raman spectroscopy is an advanced analytical technique that combines the principles of Raman spectroscopy with a swept-source laser system. It enables rapid and sensitive chemical...

Time-resolved ultraviolet photodissociation mass spectrometry (TR-UV-PDMS) is a specialized analytical technique used in mass spectrometry to study the dynamics of chemical reactions, molecular...

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...