Photonics Dictionary

The wavelength at which a lamp radiates its highest intensity.

The wavelength at which the radiant intensity of a source is maximum.

In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it. The phase mask is used to control the spatial distribution of the light's...

Microscopy technique to convert the phase structure of the wave transmitted or reflected by the specimen into a corresponding intensity structure in the image plane.

A microscope that has an annular stop in the lower focal plane of the condenser, and a quarter-wave retarding and absorbing ring in the upper focal plane of the objective that just fills the image of...

A type of matched filter that responds only to the phase of incoming light; the output has a much greater intensity than that of a classical matched filter, which responds to phase and amplitude. The...

Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently reduced or eliminated upon prolonged exposure to light. This process occurs...

A light-sensitive resistor in which resistance decreases with increase in light intensity when illuminated. The device consists of a thin single-crystal or polycrystalline film of compound...

A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical signal. Photodetectors are widely used in various applications, ranging from...

Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity of light.

The use of photoelectric sensors to detect and measure the intensity of a light source. This application, as compared to human observation, results in higher speeds of operation, a greater...

An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the intensity of the light emitted by the source.

An instrument that uses a photocell to detect and measure the intensity of incident light.

A relay that opens or closes an electrical circuit depending on the intensity of the light incident to a photoelectric device contained in the relay.

An electronic tube instrument in which the anode current varies with the intensity of light incident on the cathode.

Pertaining to the measurement of the intensity of light.

Photocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter readings are used to express illuminance and, by calibration, to measure...

Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the way the human eye perceives it. It involves the quantification of visible...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

An infrared detector in which radiation passes through a doped germanium crystal, creating a voltage drop that can be measured in terms of incident intensity.

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...

The property exhibited by a substance having electrical conductivity that decreases as the intensity of the incident visible radiant energy increases.

Photoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It measures variations in light absorption caused by the pulsatile nature of blood...

An interferometric technique for the generation of precision gratings that allows for sequential exposure of small segments in the writing of a large grating, allowing increased intensity that...

A PIN photodiode is a type of photodetector or semiconductor device used to convert light signals into electrical signals. The name "PIN" is derived from the arrangement of the three semiconductor...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a fundamental unit that represents a single point in a raster image, which is a grid of...

A plasma accelerator is a type of particle accelerator that uses electric fields and magnetic fields to accelerate charged particles, typically electrons or ions, by exploiting the motion of charged...

In optics, the Pockels effect refers to the phenomenon where the refractive index of a material changes in response to an applied electric field. This effect is utilized in Pockels cells, which are...

A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific location in space. These points are typically obtained through various sensing...

The point spread function (PSF) is a fundamental concept in imaging that describes the response of an imaging system to a point source or point object. It characterizes how a single point of light is...

A subsurface imaging technique based upon the polarization of light reflected off an object. The polarization of reflected light gives information about the object's absorption properties that...

In remote sensing technology, this represents the intensity of energy flow in the direction of wave propagation.

A pump laser is a type of laser used to provide the necessary energy to the gain medium of another laser or laser system, initiating the process of stimulated emission and producing laser light. The...

An instrument for measuring the intensity of solar radiation.

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...

A laser output that occurs when the cavity resonator Q is first kept very low, using rotating mirrors or saturable absorbers, so that the population inversion achieved is greater than usual. A high...

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...

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...

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...

An acronym for radioactive detection, identification and computation. The term refers to the detection and measurement of the intensity of emitted nuclear radiation.

A statistical analysis of facts obtained when the intensity of x-ray diffraction is calculated at different angles. In this way, the interatomic distances of gases and liquids can be deduced, with...

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 device used to measure the intensity of radiant energy.

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...