Metallic mirrors are designed for the reflection and preservation of the quality of incident radiation. It delivers high reflectance over an extensive spectral bandwidth. The coating consists of different reflective metal films with a dielectric overcoat. There are different types of metal coatings available such as Silver, Gold, Aluminum, Copper, Inconel, and Chrome. Every metal has its unique spectral characteristic. For an overall purpose visible range mirror, aluminum is the best option while silver has an excellent high reflectance over VIR and NIR range. In infrared applications for wavelengths higher than 2 microns, gold coating is preferred.
Materials used on a metallic mirror have different durability and reflection characteristics depending on the desired applications. By adding the dielectric layers on the surface of the metal coating, its reflection features are changed. Metallic mirror substrates have low scatter with extremely refined laser grade substrates at λ/10 exteriors. Moreover, it has a great impact reflected beam as it affects its state of polarization.