Toward Ultimate Nanoplasmonics Modeling

Abstract

Advances in the field of nanoplasmonics are hindered by the limited capabilities of simulation tools in dealing with realistic systems comprising regions that extend over many light wavelengths. We show that the optical response of unprecedentedly large systems can be accurately calculated by using a combination of surface integral equation (SIE) method of moments (MoM) formulation and an expansion of the electromagnetic fields in a suitable set of spatial wave functions via fast multipole methods. We start with a critical review of volume versus surface integral methods, followed by a short tutorial on the key features that render plasmons useful for sensing (field enhancement and confinement). We then use the SIE-MoM to examine the plasmonic and sensing capabilities of various systems with increasing degrees of complexity, including both individual and interacting gold nanorods and nanostars, as well as large random and periodic arrangements of ∼1000 gold nanorods. We believe that the present results and methodology raise the standard of numerical electromagnetic simulations in the field of nanoplasmonics to a new level, which can be beneficial for the design of advanced nanophotonic devices and optical sensing structures.

SQUEEZING MAXWELL'S EQUATIONS INTO THE NANOSCALE (Invited Paper)

“…Recently, it has successfully been extended to the solution of metamaterial and plamonic problems in near infrared frequencies and in optics [21,22,[24][25][26]. Based on Love's equivalence principle, metallic nanostructures can be replaced by equivalent electric and magnetic currents distributed over the boundary surfaces and interfaces.…”

“…Usually these equations are referred to as the electric current (J) CFIE, and the magnetic current (M) CFIE, as the electric current and the magnetic current are respectively well-tested in each one. The two regions defining the interface S ij are then mixed just by combining Equations (22) and (23) for regions R i and R j , yielding two single integral equations for the interface S ij as follows:…”

“…A more computationally efficient approach comprises the use of surface integral equation (SIE) formulations combined with the variational enforcement of the boundary conditions offered by the method of moments (MoM) [20][21][22]. These methods bring important advantages when compared to the above-mentioned volumetric approaches.…”

“…They enable the accurate simulation of larger plasmonic systems, assisting in the interpretation of experimental results [22]. They can also provide a priori information that reliably predicts the optical response from complex plasmonic assemblies, aiding the devise of new systems and increasing the possibilities for new fruitful discoveries [23].…”

ADAPTIVE AND PARALLEL SURFACE INTEGRAL EQUATION SOLVERS FOR VERY LARGE-SCALE ELECTROMAGNETIC MODELING AND SIMULATION (Invited Paper)

“…Applications range from advanced antenna design [8,9], stealth technologies [10,11], integrated circuits [12] to optics and photonics [13,14]. One advantage of SIE is that both the analysis and unknowns reside only on the boundary surfaces of the targets.…”