Figure 7
From: Planar Holographic Metasurfaces for Terahertz Focusing
Focusing performance of the holographic metasurfaces as a function of frequency.
Spectral behavior of the diffraction efficiency and focal peak magnitude normalized to its maximum when focusing into a single spot (left) and four spots (right). For 4-spots, the peaks from Fig. 6 (right) are numerated as follows: 1 - left, 2 - right, 3 - bottom, 4 - top.
