Photonics Dictionary

Optical elements that have been coated with one or more layers of dielectric, or metallic material. These coatings serve to reduce or increase reflection from the surface, and to protect the surfaces...

A coating that is capable of stopping the condensation of moisture on an optical surface.

An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to minimize unwanted reflections and increase the transmission of light...

An electrically conductive layer for carrying off static charges that might accumulate on a surface.

A glass substrate that has its rear surface coated with a reflective coating. Also known as a back-surface mirror.

A method of applying antireflection coatings to optics that avoids the elevated temperatures normally used. A cold coating will not be as durable as a normal coating.

A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively transmit or reflect certain wavelengths of light while simultaneously absorbing...

A shallow, fine-pitch diffraction grating having a precise dielectric overcoating that experimentally has absorbed wavelength-specific incident light that is polarized in the P-plane.

A high-reflectance coating consisting of alternating layers of quarter-wave film of a higher refractive index and lower refractive index than the substrate. Such coatings can be made very specific to...

Coating carried out in a sealed chamber evacuated by a mechanical pump in series with an oil diffusion pump to a pressure less than 10-4 mm of mercury, measured by a vacuum gauge. At such a low...

Usually a dielectric coating on glass or plastic optics; a coating that is comparable in hardness to glass itself.

A thin film of absorbing or nonabsorbing layers in which the absorption of radiation at any point is directly proportional to the electrical field intensity at that point.

An absorbing coating medium between fibers, used in some fused fiber optic plates to absorb unwanted light. Such coatings are sometimes called EMA (extramural absorption).

A self-healing, index-matching, nonporous coating for optical components that can eliminate production difficulties and deficiencies associated with solid-film contamination and postdeposition...

A thin layer of metal deposited on the surface of a substrate. The film may serve as a reflector, beamsplitter, neutral density filter or electromagnetic interference filter.

One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that substrate reflects light. For example of optical materials/optical coatings...

A coating made up of many layers of material having alternating high and low refractive index. In this way, it is possible to produce coatings with a great variety of properties. These may be...

A coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted light spectrum with no color distortion. These coatings are designed to...

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...

A layer of material applied to a coated surface to protect it from physical or chemical action.

A coating made up of particular birefringent materials having polarizing properties. It may be used, in some cases, to replace Polaroid or polarizing prisms.

In a waveguide, the material in intimate contact with the cladding surface, applied to preserve the integrity of that surface.

A film applied to a coated or uncoated optical surface primarily for protecting this surface from mechanical abrasion, from chemical corrosion, or from both. For example, a thin layer of silicon...

The thin, transparent film made up of specific substances applied to glass-air surfaces for the purpose of decreasing the amount of reflected light.

Thin-film coating, single or multilayer, that is applied to a substrate to increase its reflectance over a specified range of wavelengths. Metal film, transparent or opaque, is the oldest form of...

Thin layers intended to prevent damage to plastic optics.

A term describing an antireflection coating that may be applied to optics that cannot tolerate the high temperatures usually required for normal "hard'' coatings. Such coatings lack durability...

Spin coating is a widely used technique in the fabrication of thin films and coatings, particularly in microelectronics, optoelectronics, and nanotechnology. It involves depositing a liquid precursor...

A coating having pigments that change color when exposed to heat. This effect has been widely used to monitor hot spots in mechanical parts.

Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical, electrical, or mechanical properties. These coatings are composed of thin...

Ultraviolet (UV) coatings are specialized optical coatings designed to operate in the ultraviolet region of the electromagnetic spectrum, typically ranging from 10 nm to 400 nm. These coatings are...

A multilayer antireflective thin-film coating, so called because its reflectance rises steeply at wavelengths above and below a narrow band at zero. The v-coat is particularly useful in high-power...

Optical surface damage due to abrasive rubbing. Abrasion damage affects are less than the thickness of the optical coating layers. Surface investigation may be achieved by aluminization of the coated...

An absorbing wedge is an optical device used to control the intensity of light passing through it by absorbing a portion of the light. It is typically used in experiments and optical systems where...

An absorption spectrum is a graphical representation of the absorption of light by a material as a function of wavelength, frequency, or energy. It displays the specific wavelengths of light that are...

Actinic refers to the property of radiation, particularly ultraviolet (UV) light, that can cause photochemical reactions. Radiation: Actinic radiation typically involves UV light but can also...

Actinic glass is a type of glass specifically designed to filter or block ultraviolet (UV) light and other forms of actinic radiation. UV filtering: Actinic glass effectively absorbs or...

Actinic radiation refers to electromagnetic radiation that has enough energy to induce photochemical reactions. This type of radiation is primarily in the ultraviolet (UV) range but can also include...

Actinism refers to the property of radiation, particularly light, that enables it to produce photochemical effects. This term is derived from the Greek word aktinos, meaning ray. Here are the key...

An active-cavity radiometer is a highly sensitive instrument used to measure radiant energy (power per unit area), often in the form of electromagnetic radiation. The key features of an active-cavity...

Optical thin film adhesion specifically refers to the adhesion properties of thin films used in optical applications. Here’s a detailed definition: Thin film materials: Optical thin films...

Also known as all-glass fiber. A fiber with both a silica core and a silica cladding, regardless of the presence of a polymer overcoat or buffer.

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.

An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It serves as the primary optical element responsible for gathering and...

Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples. It is particularly useful for analyzing solid and liquid samples without...

Azobenzene is a chemical compound consisting of two phenyl rings linked by a N=N double bond. It is well-known for its ability to undergo reversible photoisomerization, meaning it can switch between...