Janus structure breaks the solar incidence angular constraint insu photothermal anti-icing

Angle-sensitive sunlight absorption in state-of-the-art photothermal anti-icing surfaces becomes an Achilles' heel: geometric shadowing and Fresnel reflection critically degrade broadband harvesting under oblique (incident light >45°) or low solar irradiation (<0.3 sun). Herein, we bridge the angular-thermodynamic paradox via laser-engineered Janus microcavities, where protruding topology maximizes oblique photon capture while recessed-bottom architectures suppress thermal conduction. This dual-scale engineering enables rapid de-icing in extreme environments (within 25 min at -20 ^oC, 0.1 sun, 60° incidence) and sustained superhydrophobicity (156 ± 2° contact angle after 50 freeze-thaw cycles). The surface maintains frost-free operation for over 72 h under a sustained low irradiance of 0.1 sun at -30 °C, while integrating exceptional wear resistance and chemical stability. This geometry-adaptive strategy unlocks omnidirectional photothermal deicing for nonplanar architectures like circuit cables and aerospace pipelines, where conventional surfaces fail under erratic solar angles, a leap toward reliable thermal management in extreme environments.