North Optics’s N-BK7 Metallic Mirrors consist of N-BK7 substrates and Enhanced Al/Protective Ag /Protective Au metallic coatings. Both stocked and custom versions are available.

N-BK7 is one of the most common materials for optical components available in large amounts, featuring low bubble/inclusion content, and decent mechanical/chemical endurance. Compared with UV-fused silica mirrors, N-BK7 mirrors are less expensive. 

Metallic-coated mirrors feature a wide reflective spectral range, low cost, and are non-sensitive to the incidence angle and polarization state. Compared with dielectric-coated mirrors, however, metal mirrors have lower reflectance and laser damage threshold, therefore metallic-coated mirrors are the economical option for applications requiring a wide rejection range and less strict reflectance standards. 

Three metal materials are utilized to coat the mirror substrates: Aluminum (Al) is the most prevalent metal for manufacturing reflection coating, it features high reflectance from UV to NIR spectrum, and is price-competitive. Silver (Ag) ’s high-reflection zone is located at visible-to-NIR, and its reflection rate is higher than aluminum, however, silver under exposure to air suffers from oxidation, which leads to blackening and degradation in performance and strength. Gold (Au) exhibits high reflectance from NIR to Far Infrared regions and is more consistent than the other two metals. The drawback is the higher cost and the soft characteristic.

North Optics is a leading supplier of optical mirrors. With over ten years of experience, we have developed our high-tech production line and in-house ISO9001-compliant inspection labs to ensure the quality of our products before dispatch. Apart from industrial-grade mirrors, we also offer super-polished mirror substrates.