Angle-Selective Photonics for Smart Subambient Radiative Cooling

• Subambient daytime radiative cooling of vertical surfaces is achieved by a sawtooth grating with a period significantly greater than the thermal wavelength. • Adjusting the grating period and aspect ratio allows the cooler to be adapted to various inclined surfaces. • Angular asymmetry and spectral selectivity effectively address the problem of thermal radiation directionality, evading ground-generated thermal radiation interference. • This work enables intelligent temperature regulation of inclined surfaces, advancing smart thermal interaction systems.