Two-Dimensional Optical Metasurfaces: From Plasmons to Dielectrics

Figure 11

(a) Diagram of the forward and backscattering characteristic of micron-sized dielectric particles. (b) Scattering plot of a 240 nm germanium sphere; refractive index is a constant and positive value in this wavelength range. Two polarizations, parallel to the incident electric field (TM or p-polarization) or consistent with the plane of incidence (TE or s-polarization) are all considered. (c) The interaction of the total extinction profile (black curve) with the wavelength is determined by the contribution of every parameter in the expansion of Mie [21]. The blue line corresponds to the contribution of the dipole and the red line to the contribution of the magnetic dipole, and approximately 1.4 microns pink depends on the magnetic quadrupole moment. (d) The phase and amplitude of the scattering field can be used as a function of wavelength of the ideal wavelength array, with electric and magnetic dipole resonance of the same intensity and width under plane wave illumination. (e) Numerical calculation of the transmission intensity (red line) and phase (blue line) of a silicon nanorod with a diameter of 484 nanometers and a height of 220 nanometers embedded in a homogeneous medium with the best optimal refractive index (n = 1.66). The resonance happens at a designed wavelength of approximately 1340 nanometers with a phase coverage of 2π. (f) Finite element simulation of the near-field distribution of scattered light in a circular amorphous silicon nanopillar (radius = 75 nm, height = 750 nm) as an example. (a, f) Corresponds to [22]; (b, c) Corresponds to [23]; (d, e) Corresponds to [24] adaptation.

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