With aluminium (Al), silver (Ag) or Gold (Au) coating, the mirror show high relfection perfance for very wide broadband. Generally, we over coat the protective SiO2 or MgF2 layer outside the metal layer to avoid the damage from the environment.
Metal coating is less sensitive to variations than dielectric coatings ,in incident angle, polarization, and wavelength

 

Substrate Material: BK7 Grade A Optical glass, Fused silica,
Tolerance: +/-0.1mm
Surface figure: L/4@632.8nm
Surface quality: 40-20
Protective chamfer
Back side unpolished or black painted upon request