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IR reflective mirrors for optical sensors
For IR gas sensors Polyteknik can provide a thin film reflective mirror coating with high reflectance and with excellent ageing properties to withstand ambient conditions such as humid climate and air pollution.

Optical gas sensor devices are often built from injection-moulded thermoplastics where the chamber walls of the sensor is deposited with either gold, silver, aluminum, nickel or copper.

The following figure shows the reflectivity of various metals as a function of wavelength. Gold and silver have at least 98% reflectivity at wavelengths above 800 nm, while aluminum has at least 94% reflectivity at wavelengths above 1000 nm.

However, generally silver, aluminum and copper, etc. oxidizes in air and thus change its optical properties. Thus, in order to prevent aging and ensure long time reliable reflective surfaces for these metals, Polyteknik has a selection of top layers that prevents oxidation and give excellent ageing properties.