Photonics Dictionary

Unlike the thermocouple or bolometer, the pyroelectric infrared detector is a current source with an output proportional to the rate of change of its temperature. Capable of extremely rapid response...

A current-source thermal detector used to detect and study the pulses obtained from particular lasers.

Device in which contact ionization of atomic particles and thermionic electron emission are used to produce magnetically confined plasma that is greatly ionized.

A device used to rapidly change the Q of an optical resonator. It is used in the optical resonator of a laser to prevent lasing action until a high level of inversion (optical gain and energy...

Q-switched operation, or q-switching, is a technique used in lasers to produce short and intense pulses of light. The term "Q" in q-switching stands for "quality factor," which is a measure of the...

Q-switching, short for "quenching-switching," is a technique used in lasers to generate short, high-energy pulses of light. The term "Q" refers to the quality factor of the laser cavity, which...

A device used in electron microscopes and particle accelerators to focus electron beams by the arrangement of four electrodes of alternating signs around the electron beam.

Quantitative oblique back illumination microscopy (qOBM) is an advanced imaging technique used in microscopy to achieve high-resolution imaging of biological samples, particularly cells and tissues....

Quantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical phase information of transparent specimens. Unlike traditional brightfield...

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...

Quantum dot light-emitting diode (QLED) is a display technology that utilizes quantum dots, which are semiconductor nanocrystals, to produce vibrant and high-quality images. QLED displays are...

Quantum dot thin films refer to thin layers or coatings composed of quantum dots deposited onto a substrate surface. Quantum dots are nanoscale semiconductor particles typically ranging from a few to...

Quantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of photonics or electronics, converts incoming photons (light) into a useful output...

Quantum key distribution (QKD) is a method of secure communication that utilizes principles from quantum mechanics to establish a shared secret key between two parties, typically referred to as Alice...

The area of optics in which quantum theory is used to describe light in discrete units or "quanta" of energy known as photons. First observed by Albert Einstein's photoelectric effect, this particle...

A quantum repeater is a crucial component in quantum communication networks, designed to extend the range over which quantum information can be transmitted. Quantum information, typically carried by...

Quantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the precision and sensitivity of measurements. Traditional sensors operate based...

A quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial dimension. This confinement leads to quantized energy levels, creating a...

The quarter video graphics array (QVGA) is a display resolution standard used in video graphics, particularly in LCD displays, digital cameras, mobile phones, and other portable electronic devices....

See crystal quartz; fused quartz.

A spectrograph used to detect radiation in the range of the ultraviolet in the electromagnetic spectrum. It is made up of quartz because that material, unlike regular glass, is not opaque to the...

Rabi oscillations are a fundamental phenomenon in quantum mechanics that describe the periodic and reversible exchange of energy between two quantum states when subjected to an oscillating external...

The analysis of the photographs taken from the radar display of a survey aircraft and used when recording terrain that is obscured by clouds.

A reflecting optic whose reflectivity is a function of the radial distance from the optic axis; can be used to convert a Gaussian beam to one of uniform cross section.

The time rate of flow of radiant energy, expressed in watts (W), and carries the units of Joule per second (J/s). The prefix often is dropped and the term "power" used.

An instrument used to recognize and identify incident radiation by the ionizing or stimulating properties of the radiation.

Any of the many devices used to detect the presence of radiation from a specific region of the electromagnetic spectrum.

Also known as radiation thermometer. A pyrometer in which the radiant intensity from the source to be measured is used to calculate its temperature. The usual detector is a thermocouple, thermopile...

A thermocouple that is used in infrared spectroscopy to detect a sample's infrared emittance. See thermocouple.

The film used in photographic dosimetry to record the types and amounts of ionizing radiation, such as x-rays and gamma rays, present in an area for a set interval of time. The negative produced by...

Plates of glass containing as many heavy metal oxides as can be dissolved in the glass without causing devitrification. The glass is yellow, very heavy and has a high refractive index. It is almost...

A device used to accelerate the electrons in a free-electron laser by channeling microwave energy into waveguide cavity assemblies.

A radioactive element that is placed or injected into a system to obtain an autoradiogram of the system. It is used in a number of fields where standard methods of internal imaging, for example,...

An instrument used to detect radioactive materials: alpha particles or helium nuclei; beta particles or free electrons; and gamma rays, which are x-rays of very short wavelength. They may be detected...

A device used to measure the intensity of radiant energy.

A microscope to which a beamsplitter and illuminated reticle have been added that is used to measure contact lenses.

A flexible fiber cable with a small diameter that transports light from the excitation laser to the target. Used in Raman spectroscopy, the probe is capable of obtaining high-quality data at high...

Raman scattering, also known as the Raman effect or Raman spectroscopy, is a phenomenon in which light undergoes inelastic scattering when interacting with matter, such as molecules, crystals, or...

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...

A photographic camera and processing system used to form a usable record of the subject in a short time, usually a few seconds, for immediate analysis.

Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally introduced into the crystal lattice of a material to modify its properties....

Rare-earth elements (REEs) are a group of seventeen chemical elements found in the Earth's crust, characterized by their unique properties and scarcity relative to other elements. Despite their name,...

In a gas, the temporary drop in density caused by contact with a sound wave.

Raster scanning is a technique used in imaging and scanning systems to systematically capture and process information from a two-dimensional area or surface. It involves moving a sensor or scanning...

Ratiometry is a technique used in various scientific fields, particularly in analytical chemistry and biochemistry, to measure concentrations or quantities by comparing the intensity of two different...