Fig. 2: Design and characteristics of meta-emitter.
From: Ultra-coherent meta-emitter tailors arbitrary thermal wavefront
a Dispersion diagrams of different spoof SPP modes. The periods of the BM, W-RM and S-RM are 0.13λ0, 0.70λ0, and 0.87λ0, respectively. Groove widths and depths are 0.06λ0 and 0.13λ0 for BM, 0.1λ0 and 0.11λ0 for S-RM. For W-RM, the width of center groove is the same as that in S-RM and other parameters are the same as those in BM. Mode profiles of single unit at frequency ω0 are shown in the right panel. b The mode lifetime (τsurf = Q/ω, τ0 = 2π/ω0, blue bars) and propagation length (\({L}_{D}={\tau }_{{\rm{surf}}}{\cdot v}_{{\rm{g}}},\,{v}_{{\rm{g}}}=\frac{{\rm{d}}{\rm{\omega }}}{{dk}}\)@ω0) along the surface (purple bars) for the above modes. The y-axis is normalized by λ0. c The eigenfrequency and mode lifetime as a function of w1. l1 = 2λ0 is set in the simulation. Inset: the eigenmode profile. d Energy tunneling efficiencies of the hybrid mode with BM on the bottom surface and BM, W-RM and S-RM on the top surface. l1 = 2λ0, w1 = λ0/150 are set in the simulation. e Eigenmode profile of the meta-emitter. The BM is configured as both the bottom and top structures in the simulation. Here, O and r represent the coordinates of the WG and an arbitrary point on the top surface, while ρ denotes the distance between these two points. f Cross-spectral density component Wzz (ρ) of the surface wave as a function of ρ at fixed height z0 = λ0/10 above the surface. g Spatial coherence of different surfaces as a function of w1.
