News

Heruioptics' Metal coatings are typically very delicate without a protective coating and require extra care during handling and cleaning. The surface of an unprotected metal coating should never be touched or cleaned with anything but clean, dry air. A dielectric overcoat on a metallic mirror allows for improved handling of the component, increases the durability of the metal coating and provides protection from oxidation with little impact to the performance of the metal coating. The dielectric layer(s) can also be designed to enhance the reflectance of the metal coating in specific spectral regions. Isopropyl alcohol or acetone can be used to clean our protected metal coated mirrors.

Protected Aluminum

Standard protected aluminum is our most popular mirror coating for applications in the visible and near infrared. A λ/2 coating of Silicon Monoxide (SiO) is typically used as an overcoat to protect the delicate aluminum. This treatment provides an abrasion-resistant surface while maintaining the performance of aluminum mirror.

Enhanced Aluminum

In an Enhanced Aluminum coating, a multi-layer film of dielectrics on top of aluminum is used to increase the reflectance in the visible or ultraviolet regions. This coating is ideal for applications requiring increased reflectance from 400 – 650nm while the UV and DUV Enhanced Aluminum coatings yield increased reflectance from 120 – 400nm range. The multi-layer film also provides the improved handling characteristics of the protected aluminum coating.

Protected Silver

Silver offers high reflectance in the visible and infrared spectral regions, making it an excellent choice for broadband applications that span multiple spectral regions. A protective coating reduces silver's tendency to tarnish but the coating still performs best in low humidity environments.

Bare and Protected Gold

Gold coatings are effective for applications requiring high reflectance in the NIR and IR regions. Since a durable coating is necessary in many applications, we offer gold with a protective overcoat. The performance of gold (96% reflectivity from 750 – 1500nm) is maintained, but the optic has a more durable finish.

Heruioptics is also a leading designer and manufacturer of laser coatings for mirrors, beamsplitters, windows, and other optical components. We work with a number of testing laboratories to independently qualify and certify our coatings for resistance to laser damage. All specified damage threshold values have been obtained by testing multiple coating runs to ensure an accurate result. The values specified are conservative, with typical data showing that our mirrors are able to withstand 2-3 times the specified threshold.