Photonics Dictionary

An InGaAs photodiode refers to a photodetector device that is constructed using a semiconductor material composed of a combination of indium (In), gallium (Ga), and arsenic (As). The term InGaAs...

Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical instruments. It refers to the specific portion of a scene that an optical...

The Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where the refractive index of a material changes in response to an applied...

A laser crystal, also known as an active medium or gain medium, is a solid-state material used in the construction of lasers. The primary function of the laser crystal is to amplify light by...

A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses are commonly used in optical systems, such as cameras, telescopes,...

The term light field refers to the spatial distribution of light rays traveling in all directions through a given space. It includes information about the intensity and direction of light rays at...

Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based semiconductor technology to create high-resolution, high-quality images. LCoS...

A long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or attenuating shorter wavelengths. These filters are designed to transmit light with a...

A machine vision system is an integrated combination of hardware and software components designed to capture, process, and analyze images to perform automated inspection, measurement, and quality...

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...

That plane in an optical system containing its optical axis and the chief ray. Also called the tangential plane.

A ray that lies in the meridional plane; a ray that lies in the plane that contains the optical axis. A tangential ray.

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...

Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as light) by spherical particles. Unlike Rayleigh scattering, which is...

The smallest angle through which light is bent by an optical element or system. In a prism, the angle of deviation is a minimum if the incident and exiting rays form equal angles with the prism...

An array of refractive microlenses that are round, square and hexagonal and as small as 15 µm. They are used for Hartmann testing, laser diode collimation and other applications that require...

An array of optically distinct fibers that are fused into one strand. They are used to keep the resolution efficiency of the smaller, single fibers and eliminate difficulty in handling. Their...

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...

Any testing method for materials and components that does not damage or destroy the test sample. Some of the methods used are x-ray, ultrasonic, electro-optic and magnetic testing.

The sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element, multiplied by the refractive index of the medium in which the vertex of the...

Optical artifacts refer to undesired or unintended effects that can occur in optical systems, such as microscopes, cameras, telescopes, and other optical instruments. These artifacts can distort or...

The point on the optical axis of a lens that is the image of the nodal points. For any bundle of rays passing through the optical center of a lens, the incident and emergent rays through this point...

Optical design software refers to specialized computer programs used by optical engineers, physicists, and designers to simulate, model, analyze, and optimize the performance of optical systems and...

The fluorographic method whereby the visible image (as opposed to the x-ray image) is photographed by mounting a camera in front of the fluorescent screen.

The relative path difference (or phase shift) traveled between two rays that pass through different mediums from the same object point. For a perfect optical system, the optical path, or distance,...

A transparent crystalline substance that displays the same optical properties (i.e. refractive index) in all directions such that all light rays behave the same in all directions of propagation and...

A transparent crystalline substance in which the refractive index of the optic axis (extraordinary axis) is different from the other two crystal axes. Two polarization directions are allowed for any...

Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter and its manifestation as both particle and wave phenomena. It encompasses the...

A discipline that combines optics and genetics to enable the use of light to stimulate and control cells in living tissue, typically neurons, which have been genetically modified to respond to light....

A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a paraboloidal surface through which the axis does not pass, and is known as an...

A ray that behaves according to paraxial equations; one that lies close to and almost parallel to the optical axis.

A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light, typically for applications such as imaging or microscopy. The photon sieve...

A plane passing through a crystal that has the optic axis of the crystal and the light ray under consideration.

Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller than the wavelength of the light. It is named after the British scientist...

An image that is formed when rays emerging from an optical system all converge to a point on the optical axis. A real image can be seen on a screen in the image space of the given optical system.

The technique for measuring the index profile of an optical fiber by scanning the entrance face with the vertex of a high numerical aperture cone and measuring the change in power of refracted...

A scanning electron microscope (SEM) is a powerful imaging instrument used in scientific research, materials characterization, and various industrial applications. Unlike traditional optical...

Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and physicist Ludwig von Seidel. These aberrations describe deviations from...

A polarizing beamsplitting prism similar in design to the Rochon prism. However, the Senarmont transmits the extraordinary ray without deviation and deviates the ordinary ray due to the orientation...

A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector specifically designed for detecting and measuring light intensity. Silicon...

Any ray through an optical system that is not a meridional ray. The plane created by a refracted skew ray does not contain the optical axis.