A plasmonic lattice mode (PLM) is demonstrated in the periodic Ag nanoparticle arrays, which are fabricated by thermal evaporation and focused-ion beam. In the arrays, each Ag nanoparticle is located on the top of a quartz trapezoidal pillar, which sits on a quartz substrate. Higher quartz trapezoidal pillars can make the transmittance of the structure vary rapidly from the maximum to the minimum in a narrow wavelength band due to the coupling between localized surface plasmonic resonance of Ag nanoparticles and the wavelength-dependent diffraction, while the phenomenon cannot be observed in the structure with lower pillars. FDTD simulation not only gives results which are similar to the experimental ones, but also shows that, when the size of Ag nanoparticles is large, it is possible to form PLM at two different wavelengths. This provides a possible way to extend the application of PLM.

An all-dielectric periodic array is proposed to form plasmon lattice resonances (PLR). In the array, Si nanopillars are on top of SiO ₂ nanopillars, and SiO ₂ nanopillars are on top of quartz substrates. The simulated results show that the line-width of the PLR can be as small as 3.3 nm. This can be attributed to the coupling between the Mie resonances of Si nanopillars and the diffracted waves. While the PLR can’t be formed by the periodic Si nanopillar array directly sitting on quartz substrates. The diameter and height of Si nanopillars, the period of the array and the height of SiO ₂ nanopillars have significant impacts on the PLR. This work extends the application of PLR.

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The figure of merit (FOM) of plasmon lattice resonance (PLR) sensors based on the array of metal/Si/SiO ₂ nanoparticles has been investigated. We demonstrate the shape and material of metal nanoparticles have remarkable effects on the PLR and FOM. FOM is governed by full-widths at half maximum (FWHM) and sensitivity of the PLR. Three different types of PLR can be generated by changing Ag nanoparticles’ shapes (pillars, cubes, spheres). One (named PLR ₁ ) is mainly originated from the coupling between Mie resonance of individual Si nanopillars and diffraction waves. PLR ₁ of Ag/Si/SiO ₂ nanoparticle arrays is limited in sensing applications due to lower intensity (for Ag pillars and Ag cubes), or smaller FOM (for Ag spheres). The other two are named PLR ₂ . PLR ₂ of Ag/Si/SiO ₂ nanoparticle array with Ag pillars (or Ag cubes) is mainly originated from the coupling between the quadrupole resonance of individual Ag nanopillars (or Ag cubes) and diffraction waves. While PLR ₂ of Ag/Si/SiO ₂ nanoparticle array with Ag spheres is mainly originated from the coupling between dipole resonance of individual Ag nanospheres and diffraction waves. The optimal Ag nanoparticles’ shape in FOM is pillar due to the smallest FWHM of PLR ₂ of Ag/Si/SiO ₂ nanoparticle array with Ag pillars. Meanwhile, a comparison of FOM between Au, Ag and Al nanopillars of fixed size is made. The optimal material of metal nanopillars to obtain a high FOM is Ag due to higher sensitivity and narrower FWHM.