Schematic diagram of an HMM Airy beam generator, where the HMM meta-atom is presented in the top right corner. The thicknesses of the metal and dielectric layers are denoted by t_m and t_d, respectively. The widths of long- and short-edges of HMM are denoted by W_l and W_s, respectively. The angle between the l axis and the x axis is the orientation angle θ. LCP plane waves normally illuminate the HMM Airy beam generator from the left-hand side.