Full-wave optimization of nanoparticle arrays for beam-steering applications

Altinoklu, Askin
Ergül, Özgür Salih
We present design and optimization of nanoarrays, which consist of metallic nanoparticles that possess plasmonic properties. Optimal two-dimensional arrangements of nanoparticles are found by using an optimization environment involving genetic algorithms and a three-dimensional full-wave solver based on the multilevel fast multipole algorithm. The nanoarrays are designed to provide maximum radiation at desired directions when they are excited via isotopic sources. The designed structures and their radiation characteristics are extensively investigated by considering various parameters, such as grid size, nanoparticle shape, distance between nanoparticles, and material. The results demonstrate the favorable radiation characteristics of the designs, as well as the capabilities of the optimization environment to design compact nanoarrays for beam-steering applications.


Full-Wave Computational Analysis of Optical Chiral Metamaterials
Guler, Sadri; Solak, Birol; Gür, Uğur Meriç; Ergül, Özgür Salih (2017-09-27)
We present computational analysis of optical chiral metamaterials that consist of helical metallic elements. At optical frequencies, metals are modeled as penetrable objects with plasmonic properties. A rigorous implementation based on boundary element methods and the multilevel fast multipole algorithm is used for efficient and accurate analysis of three-dimensional structures. Numerical results demonstrate interesting polarization-rotating characteristics of such arrays with helical elements, as well as t...
Accurate solutions of scattering problems involving low-contrast dielectric objects with surface integral equations
Ergül, Özgür Salih (2007-11-16)
We present the stabilization of the surface integral equationsfor accurate solutions of scattering problems involvinglow-contrast dielectric objects. Unlike volume formulations,conventional surface formulations fail to provide accurateresults for the scatteredfields when the contrast of theobject is small. Therefore, surface formulations are requiredto be stabilized by extracting the nonradiating parts of theequivalent currents. In addition to previous strategies forthe stabilization, we introduce a n...
Design and Optimization of Two-Dimensional Nano-Arrays for Beam Steering
Altinoklu, Askin; Rasoolzadeh, N.; Ergül, Özgür Salih (2018-03-29)
We consider design and optimization of nanoarrays involving two-dimensional arrangements of nanoparticles. Similar to their counterparts used at the lower frequencies, nanoantennas can be arranged periodically to achieve directive and/or controllable radiation patterns at optical frequencies. While nanoantenna geometries are usually simple due to restrictions in nanoscale fabrications, their robust analysis still requires accurate simulation tools that model strong plasmonic interactions between particles. ...
Fast and accurate analysis of three-dimensional structures involving near-zero-index materials
Karaosmanoglu, Bariscan; Koyaz, Yesim; İbili, Hande; Ergül, Özgür Salih (2019-09-01)
We present efficient and accurate frequency-domain analysis of three-dimensional structures involving near-zero-index (NZI) materials with very small permittivity and/or permeability values. Accurate simulations are required to analyze these homogenized models that represent metamaterials with exotic NZI properties, which can be useful in a plethora of applications. When traditional solution methods are directly applied, however, instability and inaccuracy issues arise, making solutions inefficient and inac...
Direct measurement of charge transport through helical poly(ethyl propiolate) nanorods wired into gaps in single walled carbon nanotubes
Wang, Nan; Yano, Koji; Durkan, Colm; Plank, Natalie; Welland, Mark E.; Zhang, Yan; Ünalan, Hüsnü Emrah; Mann, Mark; Amaratunga, G. A. J.; Milne, William I. (IOP Publishing, 2009-03-11)
We report the direct measurement of electrical transport through rod-like polymer molecules, of poly(ethyl propiolate) (PEP), utilizing single walled carbon nanotubes (SWNTs) as electrodes. The electrical properties of the devices were measured (i) before cutting a SWNT, (ii) when a SWNT was cut and (iii) after PEP deposition into the nanoscale gap in a cut SWNT. The gate-dependent electrical properties showed a reduction in current from I-on = 2.4 x 10(-7) A for SWNT devices to I-on = 3.6 x 10(-9) A for PE...
Citation Formats
A. Altinoklu and Ö. S. Ergül, “Full-wave optimization of nanoparticle arrays for beam-steering applications,” 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/52004.