Photonics Dictionary

A condition during laser operation when laser output can no longer be increased by additional electric current.

A sudden, brief increase in current or voltage in a circuit that can damage sensitive components and instruments. Preventive measures include slow-starter circuits, filtering and static control.

The point at which decreasing current supplied to a laser results in the extinguishing of the laser discharge.

The current that flows in a photodetector when there is no optical radiation incident on the detector and operating voltages are applied.

The minimum electrical current input needed to initiate lasing.

The positive ion current created in an electron tube as a result of the collisions between electrons and residual gas molecules.

In a laser diode, the photocurrent produced by a photodiode that detects the emission from the rear facet of the semiconductor chip. It can be used to provide feedback control of the forward current...

Any noise or current fluctuation that prevents precise measurement of the signal current. Both dark current and signal current have random fluctuations that affect the arrival of pulses. Thermal...

The current that flows through a photosensitive device, such as a photodiode, as the result of exposure to radiant power.

The electron stream emitted by a phototube when the cathode is exposed to light.

The minimum driving current corresponding to lasing threshold at a specified temperature. (Ith).

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...

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...

A signal in the form of continuously variable voltage or current.

A device that converts an analog signal, that is, a signal in the form of a continuously variable voltage or current, to a digital signal in the form of bits.

An APD detector, or avalanche photodiode detector, is a type of photodetector used to detect light or optical signals by converting incoming photons into electrical current. It operates based on the...

An arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of electricity between conductors or from a conductor to ground. Arc flashes...

A device that utilizes avalanche multiplication of photocurrent by means of hole-electrons created by absorbed photons. When the device's reverse-bias voltage nears breakdown level, the hole-electron...

An electron-beam tube in which the current to an output electrode is regulated by the transverse motion of the tube's electron beam.

In computer graphics, the point on the display screen where the electron beam is located before the display instruction is executed. On directed beam display points, vectors and other graphic...

Signal used in optical transmission systems to generate currents in a detector that are decoded with reference to a specified threshold.

Refers to transistors in which the working current flows through two types of semiconductor material: N- and P-type. In bipolar transistors, the working current consists of both positive and negative...

In avalanche photodiodes, the point at which an increase in the reverse bias voltage causes the current gain to approach infinity.

An inorganic compound, yellow to orange in color, that fluoresces strongly enough when bombarded by a high-current-density electron beam to be used as a high-intensity light source.

The storage surface of an electron beam tube that is scanned by an electron beam to generate an output-signal current corresponding to the charge-density pattern stored.

A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture...

Carrier injection refers to the process of introducing charge carriers (either electrons or holes) into a semiconductor material. Semiconductors are materials with electrical conductivity between...

An adaptation by Philips and Sony of their audio compact disc technology for optical disc data storage and retrieval. Current capacity of a disc is 0.5 to 0.6 gigabytes of information.

1. A single unit in a device for changing radiant energy to electrical energy or for controlling current flow in a circuit. 2. A single unit in a device whose resistance varies with radiant energy....

A lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.

An electrical problem that occurs when voltage is not the same with respect to ground at every node of a system, causing current to circulate between nodes.

A partially filled or empty energy band through which electrons can move easily. The material can therefore carry an electric current. The term is usually applied to semiconductors.

The coupled pairs of electrons that carry supercurrents through the body of a superconductor, relative to a coherent macroscopic wave function with the superconductor.

The quantity (C) of electricity transported in one second by a current of one ampere.

An instrument that is used to detect high-energy particles by the pulse of the current formed when a particle passes through a normally insulating crystal to which a potential difference is applied.

Deep learning is a subset of machine learning that involves the use of artificial neural networks to model and solve complex problems. The term "deep" in deep learning refers to the use of deep...

A metal coil or coils wrapped around the outside of the neck of a cathode-ray tube. Current passing through the coils produces a magnetic field, which can be used as an alternative to deflection...