Structural control of nonlinear optical absorption and refraction in dense metal nanoparticle arrays

Abstract

The linear and nonlinear optical properties of a composite containing interacting spherical silver nanoparticles embedded in a dielectric host are studied as a function of interparticle separation using three dimensional frequency domain simulations. It is shown that for a fixed amount of metal, the effective third-order nonlinear susceptibility of the composite chi((3))(omega) can be significantly enhanced with respect to the linear optical properties, due to a combination of resonant surface plasmon excitation and local field redistribution. It is shown that this geometry-dependent susceptibility enhancement can lead to an improved figure of merit for nonlinear absorption. Enhancement factors for the nonlinear susceptibility of the composite are calculated, and the complex nature of the enhancement factors is discussed.

Cascaded plasmonic metamaterials for phase-controlled enhancement of nonlinear absorption and refraction

“…where f j and χ j (3) (ω) are the fill fraction and third-order susceptibility of material j (here labeled "in" for the particle and "out" for the host material) and g j (3) (ω) is a complex, thirdorder nonlinear susceptibility enhancement factor derived from the simulated frequency-dependent linear electric field distribution E(ω,r) and is given by 18,43 …”

“…18 Figure 2 shows the calculated linear absorption spectra of the five metamaterials, obtained through the numerical integration of simulated frequency-dependent field distributions using the method described in Ref. 18. For nanoparticle arrays with a single particle size (curve E), two absorption maxima are observed.…”

“…[7][8][9] The third-order nonlinear response and corresponding figure of merit (FOM) of several nanostructured metamaterials have been investigated as a function of a variety of structural parameters. [10][11][12][13][14][15][16][17][18] A current area of particular interest involves the nonlinear optical response of systems that exhibit coupled plasmon resonances. The interaction of coupled, localized surface plasmons in dimers and particle chains, as well as their relevant spectral properties and field enhancement factors, has been studied extensively.…”

Enhanced and controllable nonlinear effects in composite with aligned gold spheroid arrays

“…[9][10][11][12] Additionally, the metal NPs have high nonlinear coefficient, which is about seven orders of magnitude higher than that of fused silica, and the LSPs can excite strong local electromagnetic field enhancements, which can produce large nonlinear enhancement, for example the enhancement of Kerr-type third-order nonlinearities scales with the fourth power of the electric field enhancement. 13,14 Therefore, composites containing metal NPs are of special interest as nonlinear materials showing various potential applications in such as enhanced two-photon fluorescence, 15 optical switches, 16 nonlinear optical absorption, 17 and so on.…”

“…13,[17][18][19] Note that in Refs. 17 and 19 they tune the composites' resonant wavelength and nonlinear enhancement by varying the particle interactions 17 or increase the size of inclusions.…”