Fluorophosphate glass is a class of optical glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

es composed of metaphosphate

Metaphosphate

A metaphosphate ion is an oxyanion that has the empirical formula PO3−. The structure of a metaphosphate ion can be described as being made up of PO4 structural units in which each unit shares two corners with another unit...

s and fluoride

Fluoride

Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...

s of various metals. It is a variant of phosphate glass

Phosphate glass

Phosphate glass is a class of optical glasses composed of metaphosphates of various metals. Instead of SiO2 in silicate glasses, the glass forming substrate is P2O5....

es.

Some fluorophosphate glasses are used as low dispersion glass

Low dispersion glass

Low dispersion glass is a type of glass with low dispersion. Crown glass is an example of a relatively inexpensive low-dispersion glass....

es. Some show anomalous partial dispersion. http://www.wikipatents.com/4859635.html One such glass is composed of Ba(PO₃)₂, Al(PO₃)₃, AlF₃

Aluminium fluoride

Aluminium fluoride is an inorganic compound used primarily in the production of aluminium. This colourless solid can be prepared synthetically but also occurs in nature.-Production and occurrence:...

, and alkaline earth fluorides MgF₂

Magnesium fluoride

Magnesium fluoride is an inorganic compound with the formula MgF2. The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics.-Production and structure:...

, CaF₂

Calcium fluoride

Calcium fluoride is the inorganic compound with the formula CaF2. This ionic compound of calcium and fluorine occurs naturally as the mineral fluorite . It is the source of most of the world's fluorine. This insoluble solid adopts a cubic structure wherein calcium is coordinated to eight fluoride...

, SrF₂

Strontium fluoride

Strontium fluoride, SrF2, also called strontium difluoride and strontium fluoride, is a fluoride of strontium. It is a stable brittle white crystalline solid with melting point of 1477°C and boiling point 2460°C.-Preparation:...

, and BaF₂

Barium fluoride

Barium fluoride is a chemical compound of barium and fluorine. It is a solid which can be a transparent crystal. It occurs in nature as the mineral frankdicksonite.-Structure:...

, with possible addition of titanium

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

, sodium

Sodium

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

, potassium

Potassium

Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

, and/or hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

. The components by wt.% are 0.5-3% Mg, 8-10% Ca, 12-20% Sr, 9-12% Ba, 7-9% Al, 5-9% P, 8-12% O, and 35-38% F.http://www.patentstorm.us/patents/4857487.html

Some doped fluorophosphate glasses are used in laser

Laser

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 technology. They are attractive here for their small refractive index nonlinearity. http://jp4.journaldephysique.org/articles/jp4/pdf/1994/04/jp4199404C4122.pdf Rare earth element

Rare earth element

As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...

s are popular dopants. One of the applications is for optical amplifier

Optical amplifier

An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed...

s.

Exotic dopants like fullerene

Fullerene

A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes...

shttp://nanofast.ucdavis.edu/Publications/doped_glasses_1994.pdf and quantum dot

Quantum dot

A quantum dot is a portion of matter whose excitons are confined in all three spatial dimensions. Consequently, such materials have electronic properties intermediate between those of bulk semiconductors and those of discrete molecules. They were discovered at the beginning of the 1980s by Alexei...

shttp://nsdl.org/resource/2200/20080912040516304T can be employed.

Tungsten

Tungsten

Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...

-doped tin

Tin

Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...

-fluorophosphate glasses (SnO

Tin(II) oxide

Tin oxide is a compound of tin and oxygen where tin has the oxidation state of +2. There are two forms, a stable blue-black form and a metastable red form.-Preparation and reactions:...

-SnF2-P2O5

Phosphorus pentoxide

Phosphorus pentoxide is a chemical compound with molecular formula P4O10 . This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant.-Structure:...

) can be used for hermetic sealing of organic light-emitting diode

Organic light-emitting diode

An OLED is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes...

s and other devices. http://www.wipo.int/pctdb/en/wo.jsp?WO=2008045249&IA=US2007021206&DISPLAY=DESC