Active Thermal Metasurfaces Enable Superscattering of Thermal Signatures Across Arbitrary Shapes and Thermal Conductivities.

The concept of superscattering is extended to the thermal field through the design of a thermal superscatterer based on transformation thermotics. A small thermal scatterer of arbitrary shape and conductivity is encapsulated within an engineered negative-conductivity shell, forming a composite that mimics the scattering signature of a significantly larger scatterer. Crucially, the enlarged thermal scattering signature substantially exceeds that of the original small scatterer and engineered shell combined, demonstrating more than mere cross-section amplification-an effect referred to as thermal superscattering. The amplified signature can match either a conformal larger scatterer (preserving conductivity) or a geometry-transformed one (modified conductivity). The implementation employs a positive-conductivity shell integrated with active thermal metasurfaces, demonstrated through three representative examples: super-insulating thermal scattering, super-conducting thermal scattering, and equivalent thermally transparent effects. Experimental validation shows the fabricated superscatterer amplifies the thermal scattering signature of a small insulated circular region by nine times, effectively mimicking the scattering signature of a circular region with ninefold radius. This approach enables thermal signature manipulation beyond physical size constraints, with potential applications in thermal superabsorbers/supersources, thermal camouflage, and energy management.