Photonics Dictionary

A technique that combines two or more imaging processes in order to minimize the disadvantages within each of the contributing processes. In medical applications, combining multiple modalities...

In an optical waveguide,- typically a multimode fiber - the distortion resulting from differential mode delay, i.e. axial rays (modes), with the shortest path length, will have the shortest...

A laser that produces emission in two or more transverse or longitudinal modes.

An optical waveguide that will allow more than one bound mode to propagate.

A method of reducing dark current in charge-coupled devices by holding all the clocks at negative voltage during the integration period.

A process involving the interaction (absorption, emission or both) of two or more photons with a molecular entity.

Characteristic of optical correlators in which invariance to more than one distortion parameter per axis of the processor is obtainable.

Also known as gatling gun laser. A system that has an array of lasers sharing a common central axis on a rotating Fabry plate to achieve increased laser firing rates by sequential Q-switching.

The series of equally spaced parallel slits that make up a scanning aperture in place of a single slit, in the scanning of a repetitive pattern.

A specific form of phase shifting interferometry - commonly referred to as multiple wavelength phase shifting interferometry - this form of interferometry utilizes two short wavelengths to synthesize...

A laser having a Q-switching method that allows separate parallel volumes of the lasing material to act independently of each other and produce several separate beams. It is useful in high-speed...

A group of related lines that represent transitions between two spectroscopic terms, each of which may be complex. Also in physics, a multiplet is recognized as a group of related subatomic particles.

The recording and mathematical analysis of all spectral intervals of the spectrometer simultaneously.

The combination of two or more signals for transmission along a single wire, path or carrier. In most optical communication systems this is referred to as wavelength division multiplexing, in which...

Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within the electromagnetic spectrum. Unlike hyperspectral imaging, which acquires...

The use of narrow bandpass filters and special photographic emulsions to discern features of a surface that would not be easily recognizable with regular black-and-white or color photographic methods.

An instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a wide spectral band, or recording many discrete spectral bands...

A monolithic laser diode incorporating multiple coupled emitters.

A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path difference to create interference between split optical wavefronts. The...

A function that quantifies the performance degradation of coherent communications systems, imaging systems and all systems that rely on the spot size of a laser beam that has propagated along an...

E.I. duPont's trade name for a polyester film. The most practical beamsplitter for use beyond the 15-µm wavelength because of its high efficiency. It exhibits high visible transmission, allowing...

A vision defect commonly referred to as nearsightedness. The defective condition results when the image of a distant object is focused in front of the retina by the relaxed eye. It can be corrected...

A symbol used to represent the refractive index. It is commonly used with a subscript to represent the wavelength of light.

In a semiconductor, the state created by the addition of a dopant that provides excess electrons.

A quadrivalent semiconductor material, with electrons as the majority charge carriers, that is formed by doping with donor atoms.

In a remote sensing system, nadir refers to the point on the ground located vertically below the center of the system. In astronomy, the nadir is the vertical direction that points towards the force...

An SI prefix meaning one billionth (10-9). Nano can also be used to indicate the study of atoms, molecules and other structures and particles on the nanometer scale. Nano-optics (also referred to as...

Nanoimprint lithography (NIL) is a nanolithography technique used for fabricating nanoscale patterns on a substrate. It is a high-resolution, high-throughput process that involves the mechanical...

An LED (light-emitting diode) is a semiconductor device that emits light when an electric current passes through it. LEDs are commonly used for lighting, displays, and indicators. A NanoLED is on the...

A unit of length in the metric system equal to 10-9 meters. It formerly was called a millimicron.

A small object that behaves as a whole unit or entity in terms of it's transport and it's properties, as opposed to an individual molecule which on it's own is not considered a nanoparticle.....