Plasmonic black coatings with broadband absorption for space applications

Abstract

Stray-light reduction is critical for the operation of optical components in space. Here, we report on the testing of high performance plasmonic broadband absorbing black coatings for space applications fabricated by metastable atomic layer deposition (MS-ALD). For this purpose, humidity testing, thermal cycling, exposure to atomic oxygen, and adhesion testing were used as testing methods. The results show that the films with thickness greater than 9 μm are able to withstand the humidity tests, thermal cycling, and exposure to atomic oxygen without significant loss of their broadband absorption. However, it was also observed that the adhesion of the films has not yet been sufficient to meet the requirements posed by the space environment. Therefore, the authors conclude that further fine-tuning of the films with respect to increasing adhesion is required to make the films suitable for space applications. Therefore, the authors propose to investigate the coating of the MS-ALD films with high refractive index coatings.