Active Thermal Wave Cloak

Active metamaterials have shown huge advantages to control electromagnetic and acoustic waves. However, how to use active metamaterials to control thermal waves has not been explored, though thermal waves are significant in various fields. To address the problem, here we report an active scheme for thermal wave cloaks. The thermal waves are based on conduction and convection, which are dominated by the Fourier and Darcy laws, respectively. By calculating the propagation of thermal waves in a free space, we can derive the global temperature and pressure distributions. We then apply these calculation results to actively control the boundary temperature and pressure, and active thermal wave cloaks can be obtained. Compared with existing passive schemes to control thermal waves, the present active scheme is more flexible for switching on/off and changing geometries. This work provides active and controllable components to thermal wave cloaks, which can be further used to design more active thermal wave metamaterials.