Photonics Dictionary

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,...

Experimental method of measuring the transmission of a given sample as a function of the wavelength.

The process of using a spectrograph with a telescope to acquire information on an astronomical object's speed and physical characteristics.

The analysis of the atomic structure of a sample by means of a source radiation that is absorbed and emitted by the sample with lines corresponding to the number and arrangement of atoms. Generally a...

The analysis of fluorescence emitted by discrete atoms, in flames, that have absorbed radiation from an external source. It is used to study the physical and chemical processes that arise from...

Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples. It is particularly useful for analyzing solid and liquid samples without...

Attosecond-pump attosecond-probe spectroscopy (APAP) is an advanced technique in ultrafast spectroscopy that allows scientists to study the dynamics of electronic processes occurring on extremely...

The energy analysis of electrons released in a secondary step following initial excitation or ionization.

A type of spectroscopy used extensively in the analysis of biological samples. Because most biologically synthesized molecules, such as proteins, are optically active, circular dichroism spectroscopy...

The spectrographic analysis of matter that is in a cooled state. Generally, a mechanical refrigerator is used to lower the temperature of the sample, allowing isolation and study of the sample and...

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 spectroscopic technique used to display the intensity of an optical pulse as functions of time and frequency simultaneously.

The use of a krypton laser system for the measurement of small molecules aligned by an electric field, by analyzing the absorption of linearly polarized light.

The spectroscopic analysis of interference patterns using an electronic imaging tube with a Fabry-Perot interferometer to record the fringes.

A type of modulation spectroscopy that measures spectral reflectance or transmittance changes induced by applying a perturbing electric field. It can be performed in contactless modes with no special...

The theory and interpretation of spectra produced by the electron emissions of substances after their irradiation by x-rays.

A type of electromodulation that measures changes in spectral reflectance.

A study of the energies and wavelengths of radiation emitted by atoms and molecules when particular physical conditions are applied to them.

The spectroscopic analysis of interference patterns using a monochannel spectrometer, spectrograph or multichannel spectrometer with a Fabry-Perot interferometer to record the fringes.

A technique in photometry that uses an oxyhydrogen or oxyacetylene flame to optically excite a solution containing the sample to be analyzed.

The study of flames by means of a laser emitting blue light and a spectrometer to measure the green fluorescence created by the flame chemistry.

The study and interpretation of the spectra of substances after they have absorbed the radiant energy emitted by a brief, intense light source.

A technique developed to measure the molecular weight of macromolecules by analyzing the spontaneous fluctuations that occur in the inherent thermodynamic concentration of solute molecules in a...

A powerful method, referred to as FCS, for determining the average diffusion coefficients of fluorescent molecules in solution or membranes. FCS measurements rely on recording the transition of...

The spectroscopic study of radiation emitted by the process of fluorescence.

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 measurement of the ability of matter to absorb, transmit or reflect infrared radiation and the relating of the resultant data to chemical structure.

A spectroscopic technique in which an excitation band absorbs laser energy resulting in an electronic transition. The isotopic species may then be measured using a time of flight mass spectrometer....

An experimental research technique by which absorbed or unabsorbed radiation is analyzed in order to characterize and determine material properties, concentration as well as behavior under the...

A method of analysis in which a pulsed laser beam is used to heat a particle, producing a plasma, or laser spark. As the plasma cools, optical energy characteristic of the elements in the plasma is...

That part of the science involved in the study of the theory and interpretation of spectra that uses the unique characteristics of the laser as an integral part in the development of information for...

A type of fluorescence spectroscopy in which an excimer laser, a dye laser and a frequency-doubling device are used to detect polycyclic hydrocarbon atoms to a part-per-billion level.

A pump-probe technique whereby a single wavelength source may be used in order to excite a given sample to determine electronic transitions.

The spectroscopic analysis of optical line shapes and frequency shifts, using the technique of light beating; i.e., the mixing of two narrowband optical components to produce an AC component in the...

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.

The analysis of structural and molecular dynamics caused by low temperature.

A method of studying the chemical and physical properties of atoms and molecules (typically living tissue and chemical samples) by exploiting the magnetic properties of their atomic nuclei when an...

Technique in which the polarization rotation of light, and its relationship to the magnetic field strength can be analyzed and related to various experimental parameters when passed through a...

A method of spectral analysis in which some property of the sample is varied and the corresponding change is measured. The change is induced by a repetitive perturbation such as an electric field,...

Spectrum analysis concerned with the spectra formed by transitions in molecules.

Spectroscopy characterized by the Mossbauer effect - recoilless emission and absorption of nuclear gamma radiation- which investigates miniscule changes in the energy levels of atomic nuclei in...

A monitoring technique used to measure the oxygen saturation levels in the brains of patients, commonly in operating room and neonatal intensive care unit settings. The technique, which is based on...

Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the electromagnetic spectrum to study the absorption of light by molecules in a sample....

That branch of spectroscopy that applies to the study of interactions between energy and atomic nuclei. The simultaneous application of a strong magnetic field and the radiation from a...

A chemical detection technique used to measure molecules that have a magnetic dipole moment. The analysis is directed to nucleuses which have a quadrupole moment which leads to an asymmetric electric...

In dry etching, a method of characterizing the composition of solid materials such as metal. Atoms in the OES technique are excited by energy that comes from a spark formed between the sample and an...

The spectroscopic study of the radiation emitted by the lifetime of phosphorescence.

A method for obtaining the optical absorption spectra of solids, semisolids, liquids and gases. PAS is inherently insensitive to reflection or scattering from the sample, analyzes opaque samples and...

A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This method may determine the extrinsic surface-state energy levels of a...