fig2

Figure 2. (A) Photograph of the left-handed metamaterial (LHM), quoted with permission from Shelby et al.^[26]; (B) The phase front of the light shows the negative refraction angle, quoted with permission from Valentine et al.^[27]; (C) Comparison between the conventional lens, metasurfaces lens, and two superlenses with negative refraction and photonic crystal slab, quoted with permission from Liu et al.^[40]; (D) Schematic showing the normal Doppler effect in normal materials (n > 0) and inverse Doppler effect in LHM (n < 0), quoted with permission from Chen et al.^[43]; (E) Schematic representation of conventional and reversed Cherenkov radiation (CR) excited via a moving charge, quoted with permission from Guo et al.^[47]; (F) Schematic of the PC containing LHM with the ray diagram for the end-fire wave propagation and suppression of radiation of a local source placed inside, quoted with permission from Shadrivov et al.^[64].