Novel Metal Oxide Metasurface-based Optical Solar Reflectors

Optical Solar Reflectors (OSRs) play a crucial role in thermal management of spacecraft as the outer-surface to the space environment. To achieve the thermal control, an ideal OSR should be able to reflect all the UV/Vis/NIR spectrum radiation to avoid heating up by the son and also emit blackbody radiation in infrared (IR) spectrum for thermal dissipation. Conventionally, OSRs are made of aluminium plated quartz tiles and therefore have serious issues for their heavy weight and fragile format, significantly adding the launch and assembly cost, respectively. Recently, we have proposed a meta-OSR solution based on thin film technology using Al-doped ZnO (AZO) [1] and the meta-OSRs can be fabricated on flexible substrates, making them light in weight and easy for surface mounting. In addition, we have also proposed a smart meta-OSR solution based on VO 2 , which has a tunable emissivity depending on the operational temperature [2] . In this work, we report a novel meta-OSR with a planar AZO metasurface unlike island-like metasurfaces formed by etch. The planar metasurface is fabricated through our patented plasma patterning technique [3] [4] , which can locally modulate carrier density in AZO.