Visualization of thermal absorption by a metamaterial absorber

We have visualized, for the first time, how a metamaterial absorber (MA) extracts heat from surrounding objects. After a certain period of heating, we observed that the temperature of the Cu plate placed on the metamaterial substrate connected to a thermoelectric device decreased more rapidly than that of the Cu plate placed on the reference substrate and device. The development of technologies to recycle waste heat is essential for achieving a decarbonized society. Thermoelectric conversion is a promising technology for recycling waste heat. However, due to its inherent limitations, power generation is not possible in an environment with uniform thermal radiation. To address this issue, we proposed and demonstrated metamaterial thermoelectric conversion, which enables power generation even in an environment with uniform thermal radiation. In our previous studies, we demonstrated that MA can cool nearby materials through thermal radiation absorption. However, no prior study has visualized the process of MA extracting heat from surrounding materials. Therefore, we aimed to observe this heat extraction process using an infrared camera.