Second-harmonic generation in metallic nanoparticles: Clarification of the role of the surface

Abstract

We present a numerical investigation of the second-order nonlinear optical properties of metal-based metamaterial nanoresonators. The nonlinear optical response of the metal is described by a hydrodynamic model, with the effects of electron pressure in the electron gas also taken into account. We show that as the pressure term tends to zero the amount of converted second-harmonic field tends to an asymptotic value. In this limit it becomes possible to rewrite the nonlinear surface contributions as functions of the value of the polarization vector inside the bulk region. Nonlocality thus can be incorporated into numerical simulations without actually utilizing the nonlocal equation of motion or solving for the rapidly varying fields that occur near the metal surface. We use our model to investigate the second-harmonic generation process with three-dimensional gold nanoparticle arrays and show that nanocrescents can easily attain conversion efficiencies of ∼6.0 × 10 −8 for pumping peak intensities of a few tens of MW/cm 2 .

Second-Harmonic Generation from Sub-5 nm Gaps by Directed Self-Assembly of Nanoparticles onto Template-Stripped Gold Substrates

“…The refractive index of the oleylamine ligand is 1. 46,45 where more details of the FDTD simulations are in the methods section. Figure 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 12 of 873 nm and a gap size of 2 nm (i.e.…”

Second-harmonic generation from metallic arrays of rectangular holes

“…Note however all bulk contributions can be cast into a surfacelike model [8], an approach that is valid in the limit of vanishing nonlocal response, as recently demonstrated from first principles by Ciraci et al within the framework of the hydrodynamic model [25].…”

“…For instance, some theoretical predictions on SHG from spherical nanoparticles, developed over more than two decades [20][21][22][23][24][25], have been experimentally tested at the single particle level only recently [26]. Nanooptics knowledge opens the possibility of future SHG-based applications for optical characterization [27][28][29][30][31][32].…”

Second Harmonic Generation by Metamagnetics: Interplay of Electric and Magnetic Resonances

“…A metamaterial consisting of coupled metal nanostrips has been shown to support both symmetric and antisymmetric displacement current flow, hence exhibiting electric and magnetic resonances for TM polarized light [4]. These structures have been termed as "metamagnetics" due to their optical magnetic response.…”