Borosilicate Glass, BK7
BK7 is one of the most common borosilicate crown glass with high homogeneity
and low bubble content. BK7 is an excellent all-around material widely used in
visible and NIR windows, lenses, and prisms.Refractive Index, n: 1.51872 @ 546.1 nm
Transmission Range: 0.35 – 2.0 µ
Thermak expansion coeff: 8.3 x 106 / ℃ at 0-200 ℃
Density: 2.51 g/cm3
UV Fused Silica (SiO2)
UV grade Fused Silica is synthetic amorphous silicon dioxide extremely high purity.
Properties include high UV transmission, low thermal expansion coefficient, and
high damage threshold.Refractive Index, n: 1.50855 @ 250.0 nm
Transmission Range: 0.18 – 3.5 µ
Thermak expansion coeff: 5.5 x 107 / ℃ at 0-200 ℃
Density: 2.20 g/cm3
Calcium Fluoride (CaF2)
Calcium Fluoride is a cubic signal crystal material grown using the vacuum
stockbarger technique with good vacuum UV to infrared transmission.
Care must be used when thermally cycling CaF2.Refractive Index, n: 1.4349 @ 546.1 nm
Transmission Range: 0.15 – 9.0 µ
Thermak expansion coeff: 1.75 x 105 / ℃ at -60-60 ℃
Density: 3.18 g/cm3
Magnesium Fluoride (MgF2)
Magnesium Fluoride is a positive birefringent crystal grown using the vacuum
stockbarger technique with good vacuum UV to IR transmission. MgF2 is
resistant to thermal and mechanical shock.Refractive Index, n: 1.4231/ 1.4367 @ 200.0 nm
Transmission Range: 0.13 – 7.0 µ
Thermak expansion coeff: 1.0 x 105 / ℃ at -60-60 ℃
Density: 3.177 g/cm3
Crystal Quartz
Crystal Quartz is a positive uniaxial birefringent signal crystal grown using a
hydrothermal process. Due to is birefringent nature, crystal quarts is most
commonly used for waveplates.Refractive Index, n: 1.54617/ 1.55535 @ 546.1 nm
Transmission Range: 0.16 – 2.5 µ
Thermak expansion coeff: / ℃ (Ⅱ), 7.1 x 106 ℃ (≤)
Density: 2.649 g/cm3
Silicon (Si)
Silicon is used as mirror substrate for lasers because of its thermal conductivity,
light weight and hardness. Due to the strong absorption at 9.0µ m, Silicon is
widely used for CO2 mirrors.Refractive Index, n: 3.436 @ 3.0
Transmission Range: 1.2 – 8.0 µ
Thermak expansion coeff: 2.55 x 106 / ℃ at 20 ℃
Density: 2.329 g/cm3
Germanium (Ge)
Germanium is used widely for lenses and windows in infrared laser systems.
Germanium is the hotter it gets the more the absorption increases. At 200Â℃
it becomes non-transmissive.Refractive Index, n: 4.0406 @ 6.0µ
Transmission Range: 2.0 – 17.0 µ
Thermak expansion coeff: 5.5 x 106 / ℃ at -60-600 ℃
Density: 5.33 g/cm3
Zinc Selenide (ZnSe)
Zinc Selenide has a very low absorption coefficient and is used extensively for
high power infrared laser optics. Zing Selenide is a relatively soft material and
scratched rather easily.Refractive Index, n: 2.4028 @ 10.6µ
Transmission Range: 0.63 – 18.0 µ
Thermak expansion coeff: 7.57 x 106 / ℃ at 20 ℃
Density: 5.27 g/cm3
Zinc Sulfide (ZnS)
Zinc Sulfide is used in harsh environments as it is harder and more resistance to
scratching. It can be used for infrared windows in high speed aicraft and vacuum
applications.Refractive Index, n: 2.201 @ 10.6µ
Transmission Range: 0.4 – 14.0 µ
Thermak expansion coeff: 6.5 x 106 / ℃
Density: 4.09 g/cm3