Fig. 1: Polaritonic Fourier crystal.
a Illustration of a 1D Fourier crystal based on a harmonically corrugated and gilded Fourier surface supporting a pristine polaritonic material. The inset shows the profile of a bi-harmonic Fourier surface used in the drawing. b Schematic of an hBN-based single-harmonic 1D Fourier crystal. When the hBN slab is placed on the gilded Fourier surface, the varying distance between hBN and gold induces the spatial modulation of the HPhP momentum in hBN. c Modes of different order experience a significantly different modulation depth in the Fourier crystal. Thus, the manifestation of the polaritonic bandgap is predicted only for the fundamental Bloch mode.
