Photonics Dictionary

For an electromagnetic field mode varying sinusoidally with time at a given frequency, the logarithmic rate of change, with respect to distance in a given direction, of the complex amplitude of any...

Irregular propagation of a wave due to variations in the medium's density or refractive index.

The propagation constant evaluated along the axis of a waveguide, that is, in the direction of transmission. Also called axial propagation wave number.

Straight line travel. This denotes the fact that light travels in a straight line when traveling through a medium with a constant refractive index.

Simulation of atmospheric turbulence for laboratory experimentation purposes, achieved by creating an unstable vertical gradient temperature in a tank filled with water.

A bulk crystalline optic which permits the propagation of light through a volume of index altered material. The variation in refractive index along the material volume is due to a piezoelectric...

A cathode-ray tube having a screen that is coated on the back with a thin film of aluminum, which serves to intensify the propagation of light.

The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and simulate the propagation of optical waves, particularly in the context of wave...

The real part of the axial propagation constant for a particular mode. The attenuation coefficient for the mode power is twice the attenuation constant.

In gradient index optics, a gradient profile in which the refractive index varies along the direction of light propagation, or optical axis. Axial gradient lenses can be used to correct spherical...

Azimuthal polarization refers to a specific polarization state of light where the electric field vector of the electromagnetic wave points along the azimuthal direction (around the propagation axis)....

1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications requiring arrayed multiple beams. 2. A mathematical 2 X 2 or 3 X 3 matrix for...

A device that measures the spatial distribution of energy perpendicular to the propagation path of a radiant beam. An energy or power meter is typically used to monitor the amount of light passing...

For light incident on a plane boundary between two regions having different refractive indices, the angle of incidence at which the reflectance is zero for light that has its electrical field vector...

A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than traditional optical techniques. CGHs are generated entirely in digital form...

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...

The distortion created because the different frequencies of a signal have different propagation velocities through a medium.

Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the direction of light propagation or polarization. The term is commonly used in...

A variation in propagation delay caused by differences in group velocity among modes of an optical fiber. Also called multimode group delay, this effect is commonly due to imperfections or any...

Propagation of electromagnetic waves through the Earth's atmosphere in a path that conforms to the curvature of the Earth due to atmospheric thermal inversion. Regions of the atmosphere act as a...

The theory of propagation of energy by combined electric and magnetic fields included in Maxwell's equations.

End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the electromagnetic waves are directed primarily along the axis or direction...

A product of the area of a light beam (normal to its direction of propagation) and the solid angle that the beam includes; flux per unit radiance or luminance. Alternative terms: geometric extent,...

A high-frequency approach to the propagation of light in graded-index fibers in which the modal field is represented in terms of an inhomogeneous (evanescent) plane wave with a complex phase, so that...

The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one location to another. Fiber optics is based off of the principle of total...

Flux per unit area measured normal to the direction of propagation of the flux.

A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at points on a silicon chip, maximizing the speed of signal propagation.

Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric shapes, such as spheres or paraboloids. Unlike conventional mirrors, which...

The area of optics that deals with the propagation of Gaussian laser beams in free space, or any general medium - i.e. lenses- under the paraxial (small divergence angle) approximations. Gaussian...

The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's Principle. Geometrical optics is useful as long as the objects in which the light...

A wave in which energy is focused near a boundary separating materials having different properties. Propagation of the wave is in a direction parallel to the boundary.

An analysis used for problems of wave propagation. The principle notes that each point of an advancing wavefront is the center of a new disturbance, the source of a new series of waves. It also notes...

A wave in the electromagnetic spectrum that has both electrical and magnetic field vectors in the direction of propagation.

A mode possessing components of both electrical and magnetic field vectors in the direction of propagation.

The gas of charged particles that begins approximately 50 km above the surface of the Earth and contains a sufficient quantity of electrons and ions to affect the propagation of radio waves.

That property of a material that determines that velocity of propagation within the material is the same for all directions.

Laser optics refers to a broad category of optical components and systems designed for manipulating and controlling laser light. Laser optics play a crucial role in shaping the characteristics of...

In photonics, a lattice refers to a periodic arrangement of optical elements or structures, often on a microscopic or nanoscopic scale. These optical lattices can be created using various techniques...

The angle between the light input propagation vector and the optical axis of an optical fiber or fiber bundle.

Luminous flux emitted from a surface per unit solid angle per unit of area, projected onto a plane normal to the direction of propagation. Also known as brightness and luminous sterance.

Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic radiation). This field of physics explores how the properties of light, such...

A shaft, spindle or any object generally passed through a workpiece to hold, support or shape a particular piece during its machining process or its practical use. In fiber optics, optical fibers are...

The linear relationship between input and output optical fields for a given optical system or application that allows the use of a matrix and matrix algebra to define an optical system, or series of...

Metasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or meta-elements, arranged in a specific pattern to manipulate the propagation of...

Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or axes. In various technical and engineering contexts, achieving precise...