Fig. 1: Thermal emission control based on dispersion engineering in a double-sided corrugated waveguide array.
a Illustration of the transition from traditional to metasurface-based thermal emitters, endowing thermal emission with temporal and spatial coherence. The right panel highlights the differences between metallic/local and dielectric/non-local structures in the control of coherence and polarization properties. b The idea of using various dispersion bands and spatial filters for thermal emission extraction. c Schematic representation of our high-coherence thermal emitter with full control of the electromagnetic properties, based on a nonlocal metasurface composed of 1D lattice of Ge waveguides, each with corrugations on both sides. The whole structures is spaced by Al2O3 from a gold mirror. A flatband design along one direction enables the use of 1D spatial filter to collect the emissions over a wide angular range without affecting the temporal coherence, indicated by the red output beam. d Demonstration of the polarization control by simply adjusting the longitudinal spacing of the corrugations, enabling a continuous control over polarization between two circularly polarized singular points.
