Mirrors are optical elements used for beam steering, manipulation and imaging. They have a highly reflective coating on at least one surface of a glass or metal substrate. The choice of substrate and coating depends on the application. The substrate may be plano or spherical (glass or metal), or may be parabolic or ellipsoidal (on-axis or off-axis; metal substrates only). Parabolic and ellipsoidal mirrors are precision CNC machined with low surface roughness to avoid scattering.
Plano mirrors can be manufactured in almost any shape: round, rectangular, elliptical, or any other shape including cut-outs and drill holes. Holes may also be drilled at an angle to the surface normal.
The design of the mirror coating depends on the technical and economical requirements of the application. We offer dielectric coatings and metal coatings with protective overcoat. Dielectric coatings are designed specifically for the application in question. Metal coatings may be aluminium, silver or gold.
Protected aluminium is economical, environmentally robust and reflects from the UV to the mid-IR. The reflectivity is not as high as for silver or gold and has an absorption dip from about 750-850nm.
Protected silver exhibits higher reflectivity than aluminium but does not extend as deeply into the UV. Silver is environmentally not as robust as aluminium and will tend to darken at the edges with time.
Protected gold is the coating of choice for IR applications. This coating has the highest IR reflectivity and is environmentally very stable.