Aluminum is characterised by its uniformly high reflection in the visible spectrum, which makes it an ideal material for the production of mirror coatings. This property is particularly valuable in applications that require efficient light reflection, such as metrology and astronomy. However, the natural tendency of aluminium to form an oxide layer leads to a decrease in reflectivity over time. Interestingly, this oxide layer provides some protection against further oxidation, which increases the longevity of aluminum mirrors. The challenge is to maintain the reflective properties over longer periods of time without compromising the optical performance.
Areas of application for aluminium coatings
The wide range of applications for aluminium coatings extends from VIS mirrors in metrology and astronomy to UV mirrors. In metrology, aluminium mirrors enable precise light reflection, which is essential for accurate measurement results. Aluminium coatings are used in diffuse reflection spectroscopy in the near-infrared range. Here they significantly improve the performance of spectroscopic instruments. UV mirrors benefit from the high reflectivity of aluminium in the ultraviolet range, making the material indispensable in many important UV-based applications on quartz. In astronomy, aluminium coatings are used on telescope mirrors to collect the light of distant stars and galaxies.