Second harmonic generation from metallo-dielectric multilayered structures in the plasmonic regime

Abstract

We present a theoretical study on second harmonic generation from metallo-dielectric multilayered structures in the plasmonic regime. In particular we analyze the behavior of structures made of Ag (silver) and MgF2 (magnesium-fluoride) due to the straightforward procedure to grow these materials with standard sputtering or thermal evaporation techniques. A systematic study is performed which analyzes four different kinds of elementary cells--namely (Ag/MgF2)N, (MgF2/Ag)N, (Ag/MgF2/Ag)N and (MgF2/Ag/MgF2)N--as function of the number of periods (N) and the thickness of the layers. We predict the conversion efficiency to be up to three orders of magnitude greater than the conversion efficiency found in the non-plasmonic regime and we point out the best geometries to achieve these conversion efficiencies. We also underline the role played by the short-range/long-range plasmons and leaky waves in the generation process. We perform a statistical study to demonstrate the robustness of the SH process in the plasmonic regime against the inevitable variations in the thickness of the layers. Finally, we show that a proper choice of the output medium can further improve the conversion efficiency reaching an enhancement of almost five orders of magnitude with respect to the non plasmonic regime.

Quenched optical transmission in ultrathin subwavelength plasmonic gratings

“…2 the planar SP modes of a uniform, 10 nm Ag layer embedded in air. As is well known, [27][28][29] in a thin metal layer (say, less than 40 nm) embedded in a symmetric environment, the typical dispersion of the single interface SP splits into two branches which correspond to guided modes with opposite properties, commonly called long-range and short-range plasmons. These findings are confirmed by the dispersion properties reported in Fig.…”

Directional beaming of light from a subwavelength metal slit with phase-gradient metasurfaces

“…For the subunit structure, d 1 , d 2 , d 3 , L y , P y and w y are fixed at 200, 60, 30, 240, 240, and 35 nm, respectively, while the other structural parameters are given in Table 1 . Ag and MgF 2 are selected as the metal layer and dielectric spacer with the relative permittivities of −27.92 + 1.52i and 1.9 at 800 nm 37 , respectively. …”

Plasmonic enhancement of second-harmonic generation of dielectric layer embedded in metal-dielectric-metal structure

“…In discussing the SHG intensity resulting from the Ag layers, we follow the arguments developed in previous SHG studies of metalo-dielectric multilayer systems. 14,16,17 In these studies, the SHG signal of the metallic layer is commonly assumed to originate from the surfaces. Furthermore, in the case of generation of p-polarized SH light by p-polarized fundamental light, it is common to take into account only the (z, z, z) components of v (2) , where the z axis is taken to be normal to the interfaces.…”