60-40 scratch & dig (MIL-PRF-13830B)
|Flatness||λ-λ/2 @ 633 nm|
|Side surfaces||fine grinding|
Polished cylinders of NiSO4*6H2O (NSH) measuring up to dia 60x40 mm are available.
Polished cylinders of K2Ni(SO4)2*6H2O (KNSH) measuring up to dia 45x20 mm are available.
Almost all UV radiation (especially 240-280nm) is absorbed by Earth ozone layer, and the UV radiation that is created by some object near the Earth surface, can be detected only using special zone filters.
Crystal materials are robust substrates from which optical filters of high purity and optical homogeneity can be fabricated. Available crystalline materials: NiSO4*6H2O (NSH) and K2Ni(SO4)2*6H2O (KNSH).