Resonant Coupling and Gain Singularities in Metal/Dielectric Multishells: Quasi-Static Versus T-Matrix Calculations

Abstract

We investigate the resonant gain response in doped multishell hybrid nanoparticles made of concentric and alternated doped dielectric and metal shells. In particular, we compare the enhanced extinction properties calculated in a quasi-static approximation with accurate light scattering calculations in the T-matrix formalism. We show that, even for small hybrid particles, a difference in the calculated optoplasmonic mode yields a dramatic change in the resonant coupling with the doped molecular system. Thus, although a simple dipole approach gives a fast qualitative view of the multishell gain-assisted response, a complete light scattering framework is crucial for a quantitative investigation of these hybrid nanosystems.

STRATIFY: a comprehensive and versatile MATLAB code for a multilayered sphere

“…Cloaking, Kerker effect [109], super-or optimally tuned scattering [51,[110][111][112][113][114][115] and absorption [20,51,113,[115][116][117][118], embedded photonic eigenvalues [119], spasing [44,47,120,121] and other intriguing phenomena [122] are easily understood from fundamental cross sections (19) and scattering patterns (20). We have summarized a self-consistent and comprehensive RTMM theory reported earlier in our [68,70] for electromagnetic light scattering from general multilayered spheres composed of isotropic shells.…”

Gain-assisted optical tweezing of plasmonic and large refractive index microspheres

“…For instance, one can dope a dielectric medium of relative permittivity h with four-level dye molecules. The resulting relative permittivity can be modeled by the dispersion relation [29,28,32]…”

“…For concreteness, we take the example of a silica host medium doped with the molecule solvatochromic dye LDS 798 [43], whose parameters are given by Refs. [29,28].…”

Enantioselective optical forces in gain-functionalized single core-shell chiral nanoparticles

“…For concreteness, we consider a realistic gain model, where the dielectric core is doped with judicious amount of dye molecules [28][29][30]. For our purpose, we consider the gain properties of solvatochromic LDS 798 dye molecules [28,31,32] in a dielectric d host, which is a well established combination to achieve active particles [33,34].…”

“…For concreteness, we consider a realistic gain model, where the dielectric core is doped with judicious amount of dye molecules [28][29][30]. For our purpose, we consider the gain properties of solvatochromic LDS 798 dye molecules [28,31,32] in a dielectric d host, which is a well established combination to achieve active particles [33,34]. The dye molecules are modelled as four level atomic systems with occupation number density N i , and 4 0 N i = N dye represents the total number of dye molecules per cubic meter.…”