Photonics Dictionary: G

Also known as amplification. 1. The increase in a signal that is transmitted from one point to another through an amplifier. A material that exhibits gain rather than absorption, at certain...

Gain-switching is a technique used in lasers to generate short pulses of light by modulating the gain of the laser medium. This method is distinct from Q-switching and mode-locking, two other common...

A galvanometer is an instrument used for detecting and measuring small electric currents. It typically consists of a coil of wire suspended in a magnetic field, with a pointer attached to the coil....

An instrument used to detect and measure the energy distribution of gamma rays. It has been used to chart the radioactivity at the lunar surface.

GaN (gallium nitride) distributed feedback (DFB) lasers refer to a specific type of semiconductor laser based on Gallium Nitride materials and designed with a distributed feedback structure. These...

A technique for measuring the concentration of any gases. Identical infrared beams are alternately chopped, one passing through a reference cell and the other passing through a cell with the gas...

In detectors, the ability to switch on and off electronically, thus producing the effect of a mechanical shutter.

Also called Geiger-Müller counter. An instrument designed to detect and measure radioactivity through the use of a gas-filled metallic tube containing a needle electrode. Radiation traveling...

Germanium crystal refers to a crystalline form of the element germanium (Ge), which is a metalloid and semiconductor commonly used in various electronic and optical applications. Germanium crystals...

A type of photoconductive detector in which germanium, usually doped with boron, gallium and indium, serves as a semiconductor and can detect up to and beyond 100 µm.

GigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data at rates of up to 1 gigabit per second (Gbps), or 1000 megabits per second...

A device that detects and measures the quantity of exposure to nuclear radiation. It uses a special glass rod that fluoresces when placed under ultraviolet radiation after its exposure to nuclear...

A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat is received by it. The bulging tilts a small mirror, which, in turn, varies...

An instrument capable of precise measurements of the Earth's gravity. This permits the detection of small changes in local height that indicate changes in the Earth's crust and subsurface density.

A process used to detect minute gravitational fields and to display images from objects by means of radiated gravitational imagery.

The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical observations when light from a distant source passes a massive object...

A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather than having a uniform refractive index like conventional lenses. This...