Photonics Dictionary

A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the near-ultraviolet (wavelengths ranging from about 300 to 400 nm). A mercury vapor...

A form of liquid crystal with an appearance of moving, threadlike structures, particularly visible when observed in thick specimens with polarized light. During this phase, the molecules of the...

A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68° between one vertical side and the end surface. The prism is cut diagonally...

Of all the rays passing through a lens from an off-axis object point to its corresponding image point, there is always one ray whose direction in the image space is equal to that in the object space....

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...

Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms, to modify their reflective and transmissive properties. These coatings are...

An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical filters are used to control the spectral content of light in various...

Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems, such as lenses, prisms, mirrors, and filters. Optical glass is...

A laser-pumped crystal with nonlinear optical properties inside of an optical resonator in which the output generates coherent light whose output can be tuned continuously over a variety of infrared...

With respect to microscopy, also called dispersive staining, optical staining the projection of colors through areas of a colorless specimen by color filters that are constructed to fit over the...

Optical switching refers to the process of controlling the routing or transmission of optical signals within a network using various techniques to selectively switch or redirect optical paths. This...

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and characteristics of optical components, systems, and devices. These instruments play a...

An organic light-emitting diode (OLED) is a type of light-emitting diode (LED) technology that utilizes organic compounds to produce light. OLEDs are commonly used in display technologies, such as...

Opsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well as in other light-sensitive tissues. These proteins play a crucial role in...

A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is mounted to rotate about a vertical axis. A slit opening in the film plane and the...

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 prism made up of two air-spaced components. It has the ability to revert, and not invert, an image, and can be used in convergent, divergent and parallel light. May be rotated to compensate for...

Phase contrast microscopy is an optical microscopy technique that enhances the contrast of transparent and colorless specimens, making it possible to visualize fine details and internal structures...

Vision by means of retinal cones; color vision. Relatively high levels of luminance are required for photopic vision.

A photovoltaic cell, commonly known as a solar cell, is a semiconductor device that directly converts light energy into electrical energy through the photovoltaic effect. The photovoltaic effect is...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a fundamental unit that represents a single point in a raster image, which is a grid of...

A polygonal mirror, also known as a multifaceted mirror or facet mirror, is a type of optical component used in various laser systems, optical scanners, and imaging devices. It consists of a flat or...

The power, expressed in prism diopters, that is the linear displacement, in centimeters, produced by the prism one meter away.

A prism is a geometric optical element with flat, polished surfaces that refract light. It is typically a solid, transparent object with at least two flat surfaces that are inclined relative to each...

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...

RGB stands for red, green, blue, which are the primary colors of light used in additive color mixing. The RGB color model is widely used in various electronic displays, such as computer monitors,...

A reflection grating is an optical component that consists of a series of closely spaced, parallel reflecting surfaces or grooves. These grooves are typically ruled or etched onto a flat substrate or...

A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or stimulus is applied at a specific frequency, causing the system to oscillate...

The retina is a light-sensitive tissue layer located at the back of the eye, opposite the lens. It plays a crucial role in the process of vision by converting light into neural signals that are sent...

Also known as reversed telephoto lens. A lens consisting of an ordinary objective with a negative component near its front focal point. Thus, the back focus is large, relative to its focal length....

A ring laser gyroscope (RLG) is a type of gyroscope that uses laser light to detect and measure changes in orientation. It operates based on the Sagnac effect, which is a fundamental principle of...

1. A device used to trace out an object and build up an image. One of the most common of these types is video scanning. The scanning takes place inside the television tube as electrons, guided by...

Vision by means of retinal rods; vision of the dark-adapted eye. In scotopic vision, the level of luminance is so low that the retinal cones are not stimulated, and there is no color vision.

Three filters used in making a color print of a color negative, red, green and blue-violet, respectively. Each filter transmits about one-third of the visible spectrum onto the print.

The combination of two waves having the same frequency and amplitude and traveling in opposite directions. Standing waves are indicated by a stationary set of nodes spaced one-half wavelength apart...

The unit solid angle subtended at the center of a sphere by an area on its surface equivalent to the square of the radius; the unit of solid angular measurement, often used in problems of...

A rangefinder similar to a pair of binoculars with a long base, a dot or other wander mark provided in each eyepiece field, together forming an apparent point in space. When one dot is moved...

Cyan, magenta and yellow. They are called subtractive because they each subtract one color by absorbtion and reflect the two others of the red, green, blue color primaries. Cyan absorbs red, magenta...

Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera, to detect and visualize the infrared radiation emitted by objects. This...