Strong spinning thermal radiation enabled by Germanium-based chiral dielectric metasurface

Spinning thermal radiation refers to the phenomenon of selective emission of circularly polarized waves from chiral structures with polarization dependence or symmetry breaking. This phenomenon finds diverse applications in fields such as radiation detection and chiral sensing. In this study, we introduce a dielectric metasurface composed of a periodic arrangement of Germanium (Ge) elliptical disks, which can exhibit circular dichroism (CD) with a maximum value of approximately 0.93 at the optimal structural parameters. The physical mechanism of the strong CD is analyzed through the polarization conversion and distributions of the electric field. Moreover, the influence of structural parameters on the spinning thermal radiation is also analyzed. It is found that the CD is closely related to the height and period of the Ge-based chiral dielectric metasurface rather than the rotation angle. This work not only provides valuable insights into the design and optimization of spinning thermal radiation using metasurfaces, but also holds promise for its engineering applications in the field of thermal detection.