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    CaF2 is a crystal,which has good transmission from 170nm to 7800nm.Its slightly soluble in water and susceptible to thermal shock.CaF2 is commonly in IR components such as windows,Lenses and prisms.

Transmission Range:170nm-7800nm

Thermal Expansion Coefficient:18.85*10-6/K




    Sapphire  is a single crystal aluminum oxide(AL2O3).It is one of the hardest materials .Sapphire has good transmission characteristics over the visible,and near IR spectrum.It exhibits high mechanical strength,chemical resistance,thermal conductivity and thermal stability.It is often used as window material in specific field such as space technology where scratch or high temperature resistance is required.

Physical Properties

Crystal Symmetry HexagonalSystem
Lattice Constanta=4.75;c=12.97
Transparence Range0.18-4.5um
Mohs Hardness
Melting Point2030℃
Thermal Conductivity0.04W/m/k
Expansion Coefficient8.4*10-6/k
Refractive Index1.755

Silicon(si) Crystals

Silicon(Si) is commonly used as a substrate  material for infrared reflectors and windows in the 1.5um-8um region.The strong absorption band at 9um makes it unsuitable for CO2 laser transmission applications but it is frequently used for laser mirrors because of its high thermal conductivity and low density.Silicon is also a useful transmitter in 20um range.

Material TypeCZ FZ;N or P
Crystal Direction{100}{111}
Resistivity (Ohm/cm)0.003-50
Thermal conductivity(J/K.M.S)163.3@273K
Density2.33g/cm³ at20℃
Melting point1410℃
Boiling point3265℃
Knoop Hardness1150
Transparency Range1000nm-10000nm,30000nm-300000nm