Fig. 1: Staggered-array metamaterial (SAMM) with extremely enhanced electromagnetic nonlinearity.
From: Mimicking bio-mechanical principles in photonic metamaterials for giant broadband nonlinearity
a A schematic of the proposed SAMM structure. The structure is infinitely periodic in all three Cartesian directions. b A single unit cell of the crystal and the positions of representative cross-sections. The cross-sections normal to the x-, y-, and z-axes are denoted as ‘csx’, ‘csy’, and ‘csz’, respectively. c A macroscopic image and a schematic of the microscopic structure of the bone (adapted by permission from Springer Nature Customer Service Centre GmbH: Springer, Int. J. Fract., Gao21). d Microscopic structure of bone fiber with and without macroscopic tensile strain. e–f Plot of the local z-directional electric-field-enhancement factor under incident x-directional electric fields, Re(Fzx), is plotted for csy and csx in Fig. 1b. g–h Plot of the local z-directional nonlinear polarization enhancement for an incident x-directional electric field, \({\mathrm{Re}}\left( {\chi _{33}^{(2)}F_{zx}^2/|\chi _{33}^{(2)}|} \right)\), is plotted.
