Dispersion characteristics of two types of two-dimension dielectric plasma photonic crystal are studied based on modified plane wave method. Firstly, the eigenvalue equations of TM mode of type-1 and type-2 structures are derived respectively; their dispersion curves are confirmed by the software simulation. Secondly, the influences of normalized plasma frequency, filling factor and relative dielectric constant on photonic band gap, and relative photonic band gap width are analyzed respectively, and some corresponding physical explanations are also given. These results would provide theoretical instructions for designing new photonic crystal devices using plasma- dielectric structure.

https://www.jpier.org/PIER/pier91/20.09022605.pdf

Modified Plane Wave Method Analysis of Dielectric Plasma Photonic Crystal

In this paper, we study tunable metamaterial structures whose unit cell has triangular split ring resonator and wire strip for S- and C-microwave bands. Three types of new metamaterials, concentric and non-concentric conflgurations, are designed, and their electromagnetic response is investigated. Constitutive and S parameters are computed using retrieval algorithm to demonstrate the properties of the proposed new metamaterial designs. In addition, the electric fleld distribution on the metallic parts of the structure is illustrated for one design of the each sample. It is shown that the studied new metamaterials exhibit double negative properties in the frequency region of interest. The main advantage of this study based on the proposed structures is having the tunability in terms of the substrate thickness and the possibility of pronounced loss reduction.

/pdf/tunable-metamaterial-design-composed-of-triangular-split-1pn1cq5azh.pdf

Tunable metamaterial design composed of triangular split ring resonator and wire strip for s- and c- microwave bands

This review article provides an overview of various novel nanowire array solar cells and highlights the aspects of electromagnetic simulations that are a valuable tool for understanding the optical processes leading to their distinct properties. As the computational methods commonly used for the task are well established, we focus on the question how numerical modeling can be used to assess the performance of a design and reveal the working principle of the devices. We conclude that scientific literature identifies numerical simulations as paramount for design and interpretation of experimental data.

/pdf/computational-electromagnetics-for-nanowire-solar-cells-584eu95o3p.pdf

Computational electromagnetics for nanowire solar cells

Calculation of the emission power distribution of microstructured OLEDs using the reciprocity theorem

Terahertz metamaterials (THz MMs) have been proven to be good candidates for chemical, biological, temperature, strain, and position sensing. However, currently developed thin-metal-film-based split ring resonator (SRR) MMs have relatively low quality factor (Q-factors), leading to a poor sensitivity, which is one of the obstacles for development of sensors. In order to enhance the Q-factor, novel THz MMs, nanopillar-based MMs, are designed, fabricated, and characterized. The nanopillar-based MMs excite the inductive-capacitive resonance via desplacement currents, showing a significantly enhanced Q-factor around 450, which is about 30 times higher than typical thin-metal-film-based MMs. Nanopillar-based MMs also show 17 times larger frequency shift compared to the metal-film-based MMs when the permittivity of the ambient dielectric properties of the MMs changes. Due to high Q-factor and large frequency shift, the nanopillar-based THz MMs utilizing displacement current have great potential for highly sensitive chemical and biomaterial detection as well as frequency-agile THz devices.

Displacement Current Mediated Resonances in Terahertz Metamaterials

Light extraction efficiency of light-emitting diodes (LEDs) based on various photonic crystal (PhC) structures is investigated in this study. By using the plane wave method and the finite element method, the influence of several factors on the enhancement of light extraction is discussed, including lattice type, the density of states from a photonic band diagram, the ratio of cylinder radius and lattice constant, and the thickness of a PHC pattern. Some rules are given for the practical implementation of an optimized PhC-based LED with higher light extraction efficiency. In the simulation results, the maximum enhancement of the extraction efficiency could be by a factor of approximately 2.8 for the optimized Archimedean tiling pattern in the LED device emitting at the center wavelength of 530 nm. However, with the use of optimized PhC structures, the square and triangular lattices reveal enhancements of ∼ 1.7 and ∼ 1.5, respectively. The extraction efficiency of the Archimedean PhC LED is much greater than that of the regular lattice PhC LED.

/pdf/design-and-modeling-for-enhancement-of-light-extraction-in-3dl7nodh3a.pdf

Design and modeling for enhancement of light extraction in light-emitting diodes with Archimedean lattice photonic crystals

The magnetic resonance of various split ring resonators (SRRs) is numerically investigated to analyze the dependence of the resonance frequency on their parameter designs. The behavior of the magnetic resonance frequency in the configuration of the 2-cut singlering SRR (2C-SRR) shows a larger shift in relation to the changes of the SRR size scaling, split width and substrate permittivity. A new magnetic particle formed by the 2C-SRR structure incorporating nematic liquid crystals (LCs) into the multilayered substrate is proposed for the realization of a tunable magnetic metamaterial. When using such inclusions, the tuning range of the magnetic resonance conditions could be as wide as ∼ 1.1GHz via changing the orientation of LC molecules by 90◦.

Comparative analysis of split-ring resonators for tunable negative permeability metamaterials based on anisotropic dielectric substrates

Light concentrating structures with three-dimensional photonic crystals (3D PhCs) for solar cell applications are investigated via simulation. The 3D opal PhCs are suggested as an intermediate layer in the concentrator system for solar cells. It is found that the light absorption is signiflcantly enhanced due to the adding of difiractive efiects of PhCs to the concentrator. Three types of PhCs are considered in four scenarios to verify the absorption enhancement by such a light concentrating structure. Our calculations show that the face-centered cubic PhC can create an absorbing e-ciency superior to the others under a specifled lattice orientation pointing to the sun, which results in an enhancement factor of 1.56 in absorption for the 500{1100nm spectral range.

/pdf/optical-absorption-enhancement-in-solar-cells-via-3d-47upgs3fj1.pdf

Jiun-Yeu Chen

Papers

Design and modeling for enhancement of light extraction in light-emitting diodes with Archimedean lattice photonic crystals

Comparative analysis of split-ring resonators for tunable negative permeability metamaterials based on anisotropic dielectric substrates

Optical absorption enhancement in solar cells via 3d photonic crystal structures