Sapphire is used for its extreme toughness and strength. Sapphire is a very useful optical window material for use in the UV, visible, and near infra-red.
Barium Fluoride is used in spectroscopic components. Barium Fluoride is often suitable for applications in the passive IR band (8 to 14μm) and is often used as a viewport window for thermography. For an equivalent thickness the transmission extends approximately 1 micron further into the IR than Calcium Fluoride. The highest quality Barium Fluoride also has application as the fastest known scintillator material and is used in High Energy Physics Experiments.
Calcium Fluoride has widespread IR application as spectroscopic CaF2 windows, CaF2 prisms and CaF2 lenses. Especially pure grades of Calcium Fluoride (CaF2) find useful application in the UV and as UV Excimer laser windows. Calcium Fluoride (CaF2) is available doped with Europium as a gamma-ray scintillator.
Germanium is a high index material that is used to manufacture Attenuated Total Reflection (ATR) prisms for spectroscopy. Its refractive index is such that Germanium makes an effective natural 50% beamsplitter without the need for coatings. Germanium is also used extensively as a substrate for production of optical filters. Germanium covers the whole of the 8-14 micron thermal band and is used in lens systems for thermal imaging. Germanium can be AR coated with Diamond producing an extremely tough front optic.
Lithium fluoride is the material with the most extreme UV transmission of all and is used for special UV optics. Lithium fluoride transmits well into the VUV region at the hydrogen Lyman-alpha line (121nm) and beyond. Lithium fluoride is also used for X-ray monochromator plates where its lattice spacing makes it the most useful analysis crystal.
Magnesium Fluoride transmits well into the VUV region to the hydrogen Lyman-alpha line (121nm) and beyond. Magnesium Fluoride is used mostly for UV optics and is excellent for Excimer laser applications.
Magnesium Oxide can be used for high temperature windows and substrates. HTSC substrates.
Optically, Crystalline Quartz is used extensively as a wave retardation medium. The birefringent properties of Quartz are of use in quarter-wave plates and in polarisers. Quartz should not be processed or used at temperatures greater than 490 °C. Crystalline quartz is also used for electronic filters and resonators. However, Crystran Ltd. does not deal in material for this application.
Silicon is used as an optical window primarily in the 3 to 5 micron band and as a substrate for production of optical filters. Large blocks of Silicon with polished faces are also employed as neutron targets in Physics experiments.
Rutile is a high index material used for coupling prisms.