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

## TL;DR

This paper introduces a thermal superscatterer that makes small objects appear much larger in terms of thermal signatures, using engineered materials and active metasurfaces.

## Contribution

The novel use of transformation thermotics and active thermal metasurfaces to achieve thermal superscattering, enabling thermal signature manipulation beyond physical size.

## Key findings

- A fabricated superscatterer amplified the thermal scattering signature of a small insulated region by nine times.
- The approach supports super-insulating, super-conducting, and thermally transparent thermal scattering effects.
- The method enables applications in thermal camouflage, energy management, and thermal superabsorbers/supersources.

## Abstract

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.

This study proposes a thermal superscatterer capable of manipulating thermal scattering signatures far exceeding the actual scale of objects. Utilizing transformation thermotics and active thermal metasurfaces, the device reproduces the thermal scattering signature of the enlarged thermal scatterer. This approach provides a versatile platform for customized thermal fields and supports the application of heat management and thermal camouflage.