Spatial and Spectral Decoupled Meta-Window for Thermal Camouflage and Infrared Communication

Thermal radiation carries energy and information, making simultaneous control of its spectral profile and spatial propagation crucial for infrared camouflage, signaling, and communication. However, most thermal materials prioritize spectral manipulation, leaving the propagation direction of broadband thermal signals underexplored and tightly coupled to the spectral response. Here, a spatial and spectral decoupled meta-window (SSDW) is demonstrated for independent control of the spectral profile and spatial distribution of broadband thermal radiation across 8-13 µm. By assigning directional reflection splitting and spectral tailoring to distinct geometric degrees of freedom, the SSDW exhibits visible haze, mid-infrared semitransparency, and broadband suppression of specular reflection, including at 10.6 µm. It maintains a stable apparent thermal signature both without external heat interference and under variations in external-source temperature, source incidence angle, and camera viewing angle. This enables visible-laser-infrared compatible camouflage, while preserving an outward channel for emergency signaling. As a proof-of-concept, the SSDW encodes the incidence direction of a 10.6 µm laser into spatial reflection patterns for assistive infrared communication, enabling reliable decoding over moderate angular variations. This work establishes spatial and spectral decoupling as a framework for thermal radiation engineering, extending control beyond radiative intensity toward coordinated heat and information pathways.