Photonics Dictionary

The minimum energy required to induce atomic and molecular separation or displacement due to incident intense laser irradiation.

The transfer of energy from an incident electromagnetic energy field with wavelength or frequency to an atomic or molecular medium.

The transition cross section constant coefficient which defines the transition probability of absorption from ground to a higher level within a given atomic or molecular species. The transition...

The wavelength or frequency corresponding to an absorption resonance with a given molecular or atomic species. The line spectrum will vary with the element as well as the molecular compound.

An absorption peak refers to a sharp increase or spike in the absorption of electromagnetic radiation at a particular wavelength or energy level. It is a distinctive feature in the absorption...

The transport of molecules in a cell which requires the use of a cell's internal energy. The energy used in the cell may be ATP as a primary transport or an electrochemical gradient give as the...

An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two thin-film transistors (TFTs) to control the on-current at each OLED cell or...

The intermolecular attraction between two surfaces, as between a substrate and a coating; it is an important factor in the durability of optical thin films.

An intermolecular substance that serves to hold materials together. Two types are used in the optical industry: one, which must be transparent and colorless, to cement lenses together; and a...

The process by which a substance, usually a solid, attracts and retains on its surface the molecules of another substance.

An angstrom, symbolized by the Ångström or Å, is a unit of length used to express atomic and molecular dimensions. It is equal to 0.1 nanometers or 1 × 10-10 meters. The...

Anisotropy refers to the property of exhibiting different values or characteristics when measured in different directions. In various fields, including physics, materials science, and geology,...

An antigen is any substance that is capable of triggering an immune response in an organism. Antigens are typically proteins or large polysaccharides, although other types of molecules can also act...

An aptamer is a short, single-stranded DNA or RNA molecule that can bind to a specific target molecule with high affinity and specificity. Aptamers are often referred to as chemical antibodies due to...

An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials science, and biology. It is a type of scanning probe microscope that...

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 photonics sources refer to devices or systems that generate extremely short pulses of light on the order of attoseconds (1 attosecond = 10-18 seconds). These ultrafast light pulses are in...

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...

Autofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when exposed to light. Unlike fluorescence that results from the application of...

The number of molecules in one gram mole of a substance, numerically approximated by 6.02 x 1023.

Azadioxatriangulenium is a type of organic compound with a unique triangular molecular structure. It is often abbreviated as ADOTA. This compound belongs to the class of polycyclic aromatic...

A spectrum that originates from molecules and that is composed of bands which, in turn, consist of many closely spaced lines. Band spectra are used to determine nuclear spin and statistics, and...

A calcium indicator is a molecule that is sensitive to changes in calcium ion (Ca2+) concentrations in biological systems. These indicators are commonly used in various fields, including cell...

A gas laser in which the energy-state transitions between vibrational and rotational states of CO2 molecules give emission at long IR, about 10 µm, wavelengths. The laser can maintain...

Chirality is a property of certain molecules and objects in which they are non-superimposable on their mirror images. In other words, a chiral object or molecule cannot be exactly superimposed onto...

The state of a liquid crystal in which the molecules are arranged in layers with their long axes in the plane of each layer. The alignment in each layer is parallel and the alignment in adjacent...

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...

Circular dichroism (CD) is a spectroscopic technique used to study the structural characteristics of chiral (asymmetric) molecules, particularly biomolecules like proteins, nucleic acids, and certain...

This type of miniaturized system, referred to as CMOS qPCR, combines microfluidic technology with an ultralow-light CMOS bio-optical sensor with LEDs as the optical excitation source to achieve...

Cold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to nanokelvin (nK) range, close to absolute zero (0 Kelvin or -273.15°C). At...

The combination of two or more different small-molecule monomers into a polymer.

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...

A small region within a single crystal where the molecules form a perfect lattice.

The selective absorption of electromagnetic waves by a liquid made up of molecules with permanent dipole movement.

Dewetting is a phenomenon in materials science and physics where a thin film or coating spontaneously undergoes a process of breaking up and forming isolated droplets on a substrate. This occurs due...

A polarizer that consists of dichroic polarizing material embedded in a plastic sheet, and that transmits light that is almost completely plane polarized with an intensity that is half that of the...

Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the direction of light propagation or polarization. The term is commonly used in...

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

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 vacuum pump in which heated oil or another substance is forced through jets as a vapor that collides with gas molecules and carries them away from the chamber being evacuated.

Electric polarization characterized by homogeneous polar dielectrics and ascribed to the position of the permanent molecular dipoles.

In a liquid crystal system, the director refers to the local symmetry axis around which the long range order of the liquid crystal is aligned. In the case of the nematic phase, the molecular long...

The spreading of potentially equal radiation frequencies that results in broadening of the spectral line. This effect is brought about when radiating atoms, molecules or nuclei have different...

A unit of energy equal to the amount of energy absorbed by one molecule of material undergoing a photochemical reaction, as determined by the Stark-Einstein law.

Three proportional coefficients labeled Am, Bmn, and Bnm, that respectively characterize the rate of spontaneous emission, induced emission, and absorption of radiation by an atom, ion or molecule.

Any material of a macromolecular nature that can stretch at room temperature to more than twice its length and return to approximately its original shape when stress is released.

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.

A spectrum band that is usually found in the visible or the ultraviolet because of the electron transitions taking place within the molecules.

An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find applications in various fields, including cathode ray tubes (CRTs), electron...