We propose a simple structure for passive sky radiative cooling made of a surface-textured layer of silica on a silver substrate. Using electromagnetic simulations, we show that the optical properties of such structures are near-ideal, due to the large reflectivity of silver in the solar spectrum and the large emissivity of silica in the infrared. Surface texturation is key to obtain near-unity emissivity in the infrared. By using thin transparent layers sandwiched between silver layers at the bottom of the structures, resonant absorption can be obtained, leading to coloration while keeping acceptable radiative cooling power. Using multiple resonator increases the color palette that can be obtained.

中文翻译：

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用于有色和无色天空辐射冷却的微结构表面

我们提出了一种简单的被动式天空辐射冷却结构，该结构由在银基板上的二氧化硅表面纹理化层制成。使用电磁模拟，我们显示出这种结构的光学特性接近理想，这是由于银在太阳光谱中的反射率大以及二氧化硅在红外光中的发射率大。表面纹理化是获得红外线中近乎统一的发射率的关键。通过使用夹在结构底部银层之间的薄透明层，可以获得共振吸收，从而在保持可接受的辐射冷却功率的同时导致着色。使用多个谐振器会增加可获得的调色板。