Dispersion of the quasi-TE (blue lines) and the quasi-TM (green lines) surface plasmons for different propagation angles (a,d) φ = 0°, (b,e) φ = 45°, (c,f) φ = 90°. Dashed lines correspond to the dispersion calculated within the effective conductivity approximation. Solid lines correspond to the calculations taking into account nonlocal interactions via the lattice sums (a–c). Color map shows the reflectance spectra of the metasurface coupled to a high-index prism with the mixed TE-TM polarization (d–f). The light line in the medium with permittivity ε = 2.1 is shown as the black line. The boundary of the first Brillouin zone is shown as the vertical solid line. The horizontal purple dashed line corresponds to the plasmon resonance according to the effective model as the insert in sub-picture (a) shows.