Photonics Dictionary

The degree to which the surface of a lens causes an incident ray of light to bend, or the amount of convergence or divergence that the surface contributes to a wavefront passing through it.

A standard source of high-charge-state ions for accelerators that has an external magnetic field oriented perpendicularly to the two cathode faces. Also called Philips ionization gauge.

A five-sided prism containing two reflecting surfaces at 45° to each other, and two refracting faces perpendicular to the entering and emerging beams. The deviation angle of 90° is...

Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS). It is a photomechanical process used to transfer...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS)....

A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a surface lubricant. Depending on motion, the transducer acts as a highly...

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...

Pushbroom scanning is a technique used in remote sensing and imaging systems, particularly in satellite and aerial sensors, to capture images of the Earth's surface or other objects. In pushbroom...

Pyramid error in optics refers to an aberration in the shape of an optical surface, particularly in the context of mirrors. It is a type of distortion that can occur when the surface of a mirror...

A narrow channel created by cleaving a crystal made of alternating layers of gallium arsenide and aluminum gallium arsenide, and adding additional layers on the cleaved end face, at right angles to...

In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis. Radial gradient lenses can focus light even when the lens surfaces are flat,...

Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene. It involves tracing the path of rays of light as they travel through a...

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...

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...

Reflectance spectroscopy is a technique used to analyze the reflective properties of materials across various wavelengths of the electromagnetic spectrum. By measuring the reflectance of light from a...

The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of radiation. It implies the capability of bouncing back or redirecting...

Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly parallel to the direction from which it originated. This occurs due to the...

A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their source, regardless of the direction from which the light approaches. Unlike...

A type of 45-90-45° prism used to bend a beam of light through a right angle with the surfaces forming the 90° angle acting as transmitting faces.

A defect in the cleaved end face of an optical fiber in which a portion of the edge has broken away; the complement of lip.

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 surface-mount device (SMD) is an electronic component that is mounted directly onto the surface of a printed circuit board (PCB) rather than being inserted into holes drilled in the board (as with...

Characterizes the significant solar radiation at the surface of the earth, so named because its spectral range extends only from 0.3 to 2.8 µm.

The method for measuring the index profile of an optical fiber by preparing a thin sample that has its faces perpendicular to the axis of the fiber, and measuring its index profile by interferometry.

A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing process to precisely cut and slice materials such as crystals, glass, and quartz...

Solar radiation intensity existing in free space at the mean solar distance of the Earth. Commonly expressed in g cal cm-2min-1, the constant is equal to the amount of incident radiation -- in unit...

Spatial resolution refers to the level of detail or granularity in an image or a spatial dataset. It is a measure of the smallest discernible or resolvable features in the spatial domain, typically...

Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating measurements at different spatial offsets. This method allows for the selective...

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface do not converge or diverge to a single focal point. Instead of focusing to a...

A defect in the cleaved end face of an optical fiber in which the surface changes abruptly.

A sputtering target is a solid material used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering targets are typically made of metals, metal alloys, or compounds...

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 semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the surface as opposed to through a cleaved mirror.

A device used to detect elevation, pyramid and resolution errors in prisms and other components by bringing them into contact with the three highly polished, flat, perpendicular surfaces that form...

Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces in contact. These materials are primarily employed in electronic devices,...

Thin-film deposition equipment refers to machinery and tools used in the process of depositing thin layers of material onto a substrate surface. This technique is commonly employed in various...

A lens having one or more toric surfaces. A toric surface is one having a maximum power in one meridian and a minimum power in a perpendicular meridian. In ophthalmic optics, toric lenses are used to...

Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other, that are arranged like the inside corner of a cube. As the triple mirror has a...

Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These particles can include sediment, silt, clay, plankton, and other microscopic...

A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates whose inside surfaces have been prepared with a special coating that aligns...