Photonics Dictionary

A reticle, also known as a reticule or graticule, is a pattern or set of markings placed in the focal plane of an optical instrument, such as a microscope, telescope, riflescope, or camera, to...

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...

1. In the geometric sense, an abbreviation for the term "sagitta,'' the height of a curve measured from the chord. and it is exact for a parabola. 2. Conforming a sheet of glass to a...

Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide (Al2O3) that is highly transparent in the infrared region of the electromagnetic...

A term used to denote the condition of a few easily visible coarse inclusions within a blank of glass.

1. In glass, a solid inclusion having a small diameter. 2. A particular, single crystal that, after undergoing the Czochralski method, evolves into large single crystals.

In multifocal spectacles, a term used to denote glass with a high refractive index that has been fused to the blank and ground to a curvature, resulting in added power.

Derived from "self-focusing,'' Nippon Sheet Glass Co. (NSG) of Japan's trade name for graded-index fiber rods with parabolic index profile, suitable for use as cylindrical microlenses.

A formed piece of glass, one surface of which has been ground and polished to the required curvatures.

An abundant material found in the form of quartz and agate and as one of the major constituents of sand. The silicates of sodium, calcium, and other metals can be readily fused, and on cooling do not...

Spots in a polished glass surface that are opaque and have a silvery, metallic reflection.

A singlet lens is an optical lens made from a single piece of material, typically glass or plastic, with one or both surfaces being spherical or aspherical. It is the most basic type of lens used in...

A gelatinous fluid that can be used as a porous thin-film coating for optical components, including laser beam collimators, or as a protective coating for glass and crystalline materials.

Optical elements arranged with no spaces between, so that the light travels only through glass, not air.

A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent light. The term "solid-state" refers to the fact that the active medium, where...

An instrument similar to the spectroheliograph, but having a scanning method that is performed by a pair of rapidly oscillating slits or a rotating glass block located before a pair of fixed slits at...

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,...

Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering is a method of depositing thin films of material onto a substrate surface...

An opaque inclusion in glass that contains undissolved or crystalline material. Also known as a seed.

In optics, the mechanical tension, compression or shear in optical glass due to internal stress caused by improper cooling or annealing during manufacture of the glass or the subsequent working of...

A viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See polariscope.

A strand of aramid yarn, steel or fiberglass in an optical cable intended to prevent bending or stretching that would damage the transport medium.

An imperfection in optical glass consisting of a distinct streak of transparent material having a slightly different refractive index from the body of glass. It is caused by improper mixing of...

Wavy transparent line in a sheet of glass appearing as though a thread of glass had been incorporated into the sheet.

Correction of an optical system at four separate wavelengths. This correction, longitudinal and lateral, is possible with the help of three selected special glasses.

The standards of MIL-O-13830 set by the US government relative to tolerable surface scratches and other such defects in an optical system. A series of standard glass plates that have been...

Also known as Fresnel reflection. That portion of the incident radiation that is reflected from the surface of a refractive material. It is a function of the refractive index of the material. At...

The material removed during diamond machining of glass components.

The series of interference bands that appear in the spectrum when a specified glass plate is inserted into a spectroscope, from the side of the blue portion of the spectrum, so that the plate...

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the principle of total internal reflection to selectively illuminate and image...

A metal box with an opal glass front enclosing a lamp, used for viewing color transparencies or x-ray films.

A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between the two negative lenses. With this system, it is possible to decrease...

Ultraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet light, which is electromagnetic radiation with wavelengths shorter than...

A type of lamp that emits a high quantity of ultraviolet radiation. This may be an arc lamp encased in a bulb of a glass that is transparent to ultraviolet rays.

A lens intended for use with wavelengths shorter than about 380 nm. It must be made of quartz, calcium fluoride, lithium fluoride or some other material transparent to ultraviolet radiation, as glass...

Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological images and structures without the need for traditional physical slides and...

An instrument that uses an erbium:glass laser to determine cloud height from the ground.

Having the characteristics of glass.

Volume Bragg gratings (VBGs) are specialized optical elements that consist of periodic variations in refractive index throughout the volume of a transparent material, typically a photosensitive glass...

Whole slide imaging (WSI), also known as virtual slide microscopy or digital pathology, is a technology that involves the digitalization of entire glass slides containing histological or cytological...