Photonics Dictionary: H

Triggering a laser at a predetermined time by pumping it to a level just below its threshold and then using an auxiliary source that quickly pumps it above threshold. Means of achieving it in laser...

A communications system that can transmit in only a single direction at a time. See duplex.

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a tungsten filament surrounded by a small amount of halogen gas, such as...

Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new photons at integer multiples of the frequency of the incoming photons....

A head-up display (HUD) is a transparent display technology that presents information directly in the field of view of a user, typically without requiring the user to look away from their usual...

The heat-affected zone (HAZ) refers to the portion of a material, typically metal, that experiences changes in its microstructure and mechanical properties due to the heat generated during welding,...

A calorimetric calculation from which the temperature vs. time dependence of any point on a sample can be determined, provided surface and bulk absorption, thermal conductivity and heat transfer...

A heat sink for a laser is a device designed to absorb and dissipate the excess heat generated by the laser during operation. This is crucial to maintain the laser's performance, prevent overheating,...

A helium-neon (HeNe) laser is a type of gas laser that emits visible red light at a wavelength of 632.8 nm. It operates based on the principle of stimulated emission of photons from excited helium...

A high-speed motion camera, also known as a high-speed camera or slow-motion camera, is a specialized imaging device designed to capture fast-moving events or phenomena at extremely high frame rates....

A shutter actuated by means other than mechanical springs for timings on the order of nanoseconds. The shutter is used in the photography of rapid moving objects or events.

A still camera with a shutter capable of opening for a time as short as a fraction of a microsecond. An electronically operated Kerr cell often is employed.

A holographic camera, also known as a holographic imaging system or holographic recorder, is a specialized device used to capture 3D holographic images of objects or scenes. Unlike conventional...

A method of measuring flow velocity by seeding the flow with neutrally buoyant particles and using a pulsed laser to holographically record particle displacement during a short time period. An...

Homogeneous light refers to light that is uniform in intensity and color across a given area or space. In other words, homogeneous light sources produce illumination that is consistent and evenly...

Device in which the various circuit elements are fabricated in different substrate materials and then appropriately joined together so that the various substrate materials can be chosen to optimize...

That object distance at which a camera must be focused so that the far depth of field just extends to infinity. The near limit of the depth of field is then half the hyperfocal distance. For normal...

Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the electromagnetic spectrum. Unlike traditional imaging systems that record only a few...

A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide range of wavelengths within the electromagnetic spectrum, typically from...