Photonics Dictionary

An Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet (Er:Y3Al5O12) as the gain medium. The erbium (Er) ions are introduced into the crystal...

An acid used to etch the surfaces of particular materials. For glass, hydrofluoric acid is used either as a liquid or a vapor. Metals are etched by means of suitable acids or other liquids, often to...

An exciton is a quasiparticle that represents the bound state of an electron and a hole in a solid-state material, typically a semiconductor or an insulator. In simpler terms, an exciton is a paired...

1. The near total absorption of plane-polarized light by a polarizer that has an axis perpendicular to the plane of polarization. 2. The decrease in the intensity of a diffracted beam resulting from...

A ray that has a nonisotropic speed in a doubly refracting crystal. It does not necessarily obey Snell's law upon refraction at the crystal surface.

The properties exhibited by a semiconductor as the result of its modification by imperfections and impurities in the crystal.

With respect to a unit cell in a crystal structure, the property defining an atom located at the center of each face.

The Faraday effect, named after the English scientist Michael Faraday, is a phenomenon in physics where the polarization plane of light is rotated when the light passes through a transparent medium...

The region of a ferroelectric crystal where spontaneous polarization is uniformly directed.

Ferroelectric materials are a type of dielectric materials that exhibit spontaneous electric polarization, meaning they possess a permanent electric dipole moment even in the absence of an external...

The phenomenon whereby certain crystals exhibit spontaneous electric polarization. It is analogous with ferromagnetism.

An electronic display in which a flat screen is formed by an orthogonal array of display devices, such as electroluminescent devices, light-emitting diodes or liquid crystal cells.

Fluoride fibers are optical fibers made from fluoride-based materials, typically fluoride glasses or crystalline fluoride compounds. These fibers are characterized by their unique optical properties,...

The optical form of the crystal fluorspar, calcium fluoride, that is utilized for its low optical dispersion, its low refractive index, and its transparency to infrared and ultraviolet radiation.

A method of synthesis for crystals such as KTP. The process involves the use of a high-temperature solution called flux to enable crystal growth. Flux dissolves the elements of the desired crystal,...

A salt of formic acid that can be used to enhance the photosensitivity of silver halide crystals.

A solid-state laser consisting of active atoms or ions of a transition metal, rare-earth metal or actinide, imbedded in a crystal or glass material, often garnet. Excitation and transfer to different...

A crystal defect that is a combination of a vacancy and an interstitial created by the removal of an ion from a lattice and its placement in an interstitial position.

Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO2), but they are produced through different manufacturing processes and have distinct properties...

A crystalline semiconductor alloy used as the light confinement layer in both single- and double-heterostructure diode lasers.

A laser system consisting of a planar PN junction within a single crystal of gallium arsenide. The pair of parallel, semireflective end faces produces a Fabry-Perot resonant cavity, whereas the other...

Gallium arsenide phosphide (GaAsP) is a semiconductor alloy composed of gallium (Ga), arsenic (As), and phosphorus (P). It is commonly used in the fabrication of optoelectronic devices, particularly...

A crystalline semiconductor material that transmits in the infrared.

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides. Common window or bottle glass is a mixture of soda,...

A type of glass used in telescope mirrors, formed by adding a nucleating agent to standard glass and then heating it until it crystallizes.

The plane shared by the pair of axes in a twin crystal.

A crystal of microscopic size having no definite plane faces and having a globular shape. At the time the crystal is formed, the strong surface tension influences the formation of the plane faces.

In a multicrystalline material, the meeting point between crystallites.

In a microscope, the diaphragm located between the Bertrand lens and the eyepiece, which is closed during conoscopic viewing to restrict the interference figures to that of a crystal lying on the...

Gram-negative bacteria are a group of bacteria that possess a cell envelope composed of a thin layer of peptidoglycan surrounded by an outer membrane. This outer membrane contains lipopolysaccharides...

Gram-positive bacteria are a group of bacteria that have a thick cell wall composed primarily of a substance called peptidoglycan. This thick peptidoglycan layer retains a stain called crystal violet...

High-modulus elastic fibers that exhibit the following differences from conventional elastic fibers: Increasing temperature decreases recovery force (the fibers are enthalpic vs. conventionally...

Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new photons at integer multiples of the frequency of the incoming photons....

Holmium lasers are a type of medical laser that utilizes holmium-doped crystals as the gain medium. The term holmium laser is often associated with a specific type of laser used in urology for...

With respect to a crystal, the characteristic of possessing two ends symmetrical with each other.

The perpendicular orientation of the molecular axes of the nematic molecules in a nematic crystal, relative to the electrode plates.

The parallel orientation of the molecular axes of the nematic molecules in a nematic crystal, relative to the electrode plates.

A method of manufacturing polycrystalline infrared-transmitting optical fiber by heating a single halide crystal billet and forcing it through a die.

Also called calcite. A natural hexagonal crystal of calcium carbonate. It cleaves readily into rhomboids useful in the study of polarized light.

Pertaining to the possession of photoelectric characteristics as a result of the properties of the true crystal and not of foreign materials.

Term synonymous with refractive index liquid, but related more to tank or chamber immersion of crystals, fibers, lenses, photoelastic models, etc.

An alien, electrically charged atomic system in a solid; an ion substituted for the constituent atom or ion in a crystal lattice, or located in an interstitial site in the crystal.

In the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within the material that deviate from its regular or intrinsic composition. These...

Metal used in components of the crystalline semiconductor alloys indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP), and the binary semiconductor indium phosphide (InP)....