High Reflectiance Metallic Coatings

Opti-Forms offers a wide range of standard metallic coatings. The performance of each of these coatings are displayed in the reflectivity graph.

Most requirements can be satisfied with our standard coatings available, although specifc tuning of reflectance properties can be designed to meet your optical design requirements. Please contact our Thin Film Group and talk to one of our friendly and knowledgeable sales engineers.

Bare Gold

Totally inert with excellent infrared reflectance, this electro-deposited precious metal, also available vacuum deposited, is the ideal choice for broad band infrared use. In many applications the low durability of gold can be tolerated in exchange for reflectance of over 96% at a wavelength from one to over ten microns.

Bare Silver

Silver has the highest visible reflectance, 98%, of all the common evaporated metals.  Silver is also highly reactive to many chemical species, including water, and compounds of sulfur.  Bare silver is not recommended as an optical coating solution since degradation begins immediately upon removal from the deposition chamber.

Bare Aluminum

The average visible reflectance of the bare Ni substrate is approximately 62%.  By overcoating the bare Ni substrate with vacuum deposited Al the average visible reflectance increases to 91%. Thin film bare aluminum is delicate and scratches easily.  Evaporated thin film aluminum is also susceptible to  mechanical and optical degradation in use and in storage, depending on environmental factors.

Protected Aluminum

Silicon Dioxide (SiO2) overcoated aluminum (commonly called AQ), also vacuum deposited, exhibits over 90% reflectance across the visible spectrum, with good handling characteristics. While not as durable as rhodium, it has improved reflectance with slightly increased cost.

Enhanced Aluminum

For applications where visible reflectance requirements are higher than 91% but less than near unity, the enhanced aluminum optical coating is suggested.  This coating provides high visible reflectance, approximately 95%, as well as improved scratch resistance compared to a bare aluminum overcoat.

Protected Silver

Protected silver retains the high reflectance of bare silver and also has improved environmental and mechanical stability due to the addition of a protective layer.

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