Metallic Mirror

Mirrors are optical components that operate based on the law of reflection, primarily used for beam redirection, interferometry, imaging, or illumination. The characteristics of a mirror depend on its optical coating, substrate, and surface quality. The standard manufacturing process involves applying a coating to a highly polished substrate material. The performance of the optical mirror varies depending on the substrate material and the coating material and process used. Common substrate materials include N-BK7 optical glass, fused silica, and float glass. The optical coating determines the reflectivity and stability of the mirror, making it the most critical component of the mirror. Mirror coatings are typically made from metallic or dielectric materials. The metal mirror, that is, a metal film layer is plated on the substrate to achieve light reflection. The metal film has a very wide reflective spectral band, but it is often accompanied by a certain light absorption. More optical metal mirrors in the market are mainly aluminum mirrors, gold mirrors and silver mirrors. Aluminum Mirrors Aluminum mirrors are typically produced by vaporizing aluminum onto a highly polished planar substrate. These mirrors are not limited by the angle of light incidence, making them versatile for various applications. Depending on the specific use case, aluminum-coated mirrors can be customized in several ways, such as: Mirrors with only aluminum coating. Mirrors with a protective coating over the aluminum layer to prevent damage. Mirrors with a protective coating to enhance reflectivity in the ultraviolet (UV) wavelength range. Mirrors with a protective coating on parallel planar substrates. Aluminum-coated mirrors exhibit high reflectivity (>90%) across the UV to infrared (IR) spectrum, and their optical coatings are relatively robust compared to those made from other metallic materials. ATOPTIK offers aluminum coatings with a protective layer, achieving reflectivity greater than 93% in the wavelength range of 450 - 700 nm. Gold Mirrors Goldmirrors are typically used in the near-infrared (NIR) and infrared (IR) spectrum ranges. During the fabrication of gold-coated mirrors, substrates with high thermal conductivity, strong adhesion for gold coatings, and excellent thermal resistance are preferred. Common substrates include silicon-based materials or float glass. In practical applications, gold coatings provide high reflectivity for infrared and near-infrared light, with unreflected light being absorbed by the gold layer rather than passing through the substrate. Gold-coated mirrors exhibit better strength and stability compared to silver-coated mirrors. ATOPTIK offers gold coatings with a protective layer that achieves an average reflectivity greater than 96% across the working wavelength range of 650 nm - 20.0 μm. The product is available in various sizes, including circular and square options for flexibility in application needs. Silver Mirrors Silver coatings exhibit excellent reflectivity in the visible to infrared (IR) wavelength range. Compared to aluminum-coated mirrors, silver-coated mirrors offer higher reflectivity in the visible to infrared spectrum. Unlike dielectric-coated mirrors, silver-coated mirrors are not affected by the angle of light incidence. However, silver coatings have poor adhesion to optical glass substrates, requiring an additional protective layer during fabrication to slow down silver oxidation and extend its service life. ATOPTIK offers silver-coated mirrors with a silica protective layer, achieving an average reflectivity greater than 96% across the working wavelength range of 450 nm - 20.0 μm. These mirrors are available in various shapes, including circular, square, and D-shaped designs to meet different application requirements.

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