Photonics Dictionary

Trade name referring to an instrument that determines surface distances by measuring the length of time it takes for a modulated lightwave to reach a mirror and be reflected to its point of origin.

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...

Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing or inactivating microorganisms, including bacteria, viruses, and fungi. The...

A grating beamsplitter is an optical device that utilizes the principles of diffraction to split a beam of light into multiple beams, often redirecting them at specific angles. It is based on the...

A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather than having a uniform refractive index like conventional lenses. This...

Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a hyperspectral imaging system. In hyperspectral imaging, the electromagnetic spectrum is...

The distance from the last surface of a lens system to the image. For a thin lens system, this distance is equivalent to the distance from the rear nodal point of a lens to the image.

A ray of light that falls upon or strikes a surface of an object such as a lens. It is said to be incident to the surface.

An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the infrared radiation emitted by objects, revealing temperature variations across...

An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible spectrum of light. These detectors are utilized in various applications,...

Any object that emits radiation of a wavelength lying between about 0.75 to 1000 µm. A calibrated secondary source usually is a heated cavity (blackbody) or a filament lamp rated in wattage...

An instrument that employs the interference of lightwaves to measure the accuracy of optical surfaces; it can measure a length in terms of the length of a wave of light by using interference...

A nonoptical surface, within lenses and lens mounts, that contributes largely to flare by reflecting light into the image space. As a result, such surfaces, so located, are finished with a dull...

The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from superficial layers in the surface of a material.

A curve or surface having equivalent light intensity.

A metal tool used to grind lenses with loose abrasive (see diamond cutting tool). The functional surface of the lap is carefully formed to be opposite the curve to be produced on the glass (concave...

A lateral shearing interferometer is an optical device used in interferometry to measure phase differences between two beams of light. Interferometry is a technique that combines and analyzes...

A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which lenses are eventually fabricated. Lens blanks are made from various...

A tool used to determine the curvature of a lens surface in terms of dioptric power. See lens watch; spherometer.

A line passing through the center of a lens surface, from edge to edge.

Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance, quality, and characteristics of lenses. These instruments are essential for...

An array or mosaic of optical surfaces. May be a number of lenses closely packed to form multiple images or many parallel cylinders used as a projection screen.

A rear or front projection screen composed of minute optical surfaces that introduce a spread to the light beam that conforms approximately to the light distribution requirements of the application.

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...

Luminosity refers to the total amount of energy emitted by an astronomical object, typically measured per unit time. It quantifies the intrinsic brightness of the object and is often expressed in...

A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is focused on the lens surface at a point diametrically opposite the...

Magnetorheological finishing (MRF) is a precision optics polishing technique used for shaping and finishing optical surfaces to achieve extremely high levels of smoothness and accuracy. It is...

A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens and second rear surface is a spherical mirror. This combination utilizes...

The distortion in an ophthalmic lens resulting from the refraction of light rays entering the periphery of the lens surface. It increases relative to the power of the lens.

A lens that has one convex surface and the other concave.

Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication, and utilization of artificial structures called metasurfaces to control and...

A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light at a subwavelength scale. Unlike traditional lenses made of glass or other...

A specially designed microscope for observing the etched surface of a polished metal specimen. The specimen is often laid face down on a horizontal stage and observed from beneath, the illumination...

A small optical polishing machine intended for polishing the surface of a metal specimen before etching for examination under a microscope. Although shaping and polishing machines for this purpose...

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...

A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle detection, imaging, spectroscopy, and night vision technology. It consists of a...

The formation of transistors, diodes, capacitors, resistors and other electronic elements directly on a flake of silicon by etching and selective absorption of doping elements. A circuit diagram...

A technique for producing micron-size structures on surfaces by using short-wavelength light or electron beams.

Mode hopping in the context of lasers refers to a phenomenon where a laser system abruptly switches from one longitudinal mode to another. In a laser, different longitudinal modes represent distinct...

A blank whose basic surface curves are attained by heating and forming a given weight of raw glass; a rough glass blank resembling the finished lens in size and shape. After molding, a precision lens...

A molded lens is an optical lens manufactured using a molding process, typically involving the shaping of a material, such as glass or plastic, into the desired lens shape. This process involves...

A metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor material. Unlike the more common PIN photodiodes, which have a P-type and...

Nanoplasmonics is a branch of nanophotonics that focuses on the study and manipulation of optical phenomena at the nanoscale using plasmonic materials and structures. Plasmonics deals with the...

A defect in infrared systems that appears as a dark circular area on a displayed image, caused by radiation reflecting into a detector. It can be reduced by low-reflective coatings or by altering the...

An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be used to detect minute flaws or to image faint marks that are made in the...

A scanning probe microscope that analyzes the surface of a specimen by recording the intensity of light as it is focused through a pipette and raster scanned across the specimen at a distance less...