A. M. Heikal

Ultra-high tunable liquid crystal-plasmonic photonic crystal fiber polarization filter.

A novel ultra-high tunable photonic crystal fiber (PCF) polarization filter is proposed and analyzed using finite element method. The suggested design has a central hole infiltrated with a nematic liquid crystal (NLC) that offers high tunability with temperature and external electric field. Moreover, the PCF is selectively filled with metal wires into cladding air holes. Results show that the resonance losses and wavelengths are different in x and y polarized directions depending on the rotation angle φ of the NLC. The reported filter of compact device length 0.5 mm can achieve 600 dB / cm resonance losses at φ = 90° for x-polarized mode at communication wavelength of 1300 mm with low losses of 0.00751 dB / cm for y-polarized mode. However, resonance losses of 157.71 dB / cm at φ = 0° can be achieved for y-polarized mode at the same wavelength with low losses of 0.092 dB / cm for x-polarized mode.

Highly Sensitive Plasmonic Photonic Crystal Temperature Sensor Filled With Liquid Crystal

A novel highly sensitive surface plasmon resonance-based liquid crystal (LC) photonic crystal fiber (PCF) temperature sensor is presented and studied. Through this letter, the coupling characteristics between the core guided mode inside the PCF core infiltrated with nematic LC and surface plasmon mode on the surface of nano gold wire are studied in detail. The structural geometrical parameters of the proposed design, such as number of metal rods, core diameter, and metal rod diameter are optimized to achieve highly temperature sensitivity. The suggested sensor of compact device length of 20 μm proved to surpass the recent sensors with high sensitivity of 10 nm/°C. The results are calculated using a full-vectorial finite-element method with irregular meshing capabilities and perfectly matched layer boundary conditions.

Improved Trenched Channel Plasmonic Waveguide

In this paper, the modal analysis of a novel design of three trenched single mode channel plasmon polariton is introduced and analyzed using the full-vectorial finite difference method for linear oblique and curved interfaces (FVFD-LOCI). The analyzed parameters are the real effective index, propagation length, and lateral mode radius r3dB. In addition, the figure of merit (FOM) defined as the ratio between propagation length and lateral mode radius is also studied. The analysis is performed for different channel plasmon polariton (CPP) waveguides; trenched-groove, V-groove and the suggested three trenched structure over a specific spectral range (200-550 THz). The selected band of frequency is chosen to ensure the existence of the CPP fundamental mode. The reported design offers very high FOM at low frequency band (200-350 THz) compared to the well known V-groove structure. However, the lateral mode radius r3dB of the suggested three trenched structure is slightly smaller than that of the V-groove structure. For high frequency band (350-550 THz), the FOM is still higher than that of the V-groove structure while the lateral mode radius r3dB is slightly greater than that of the V-groove structure.

Efficient Polarization Filter Design Based on Plasmonic Photonic Crystal Fiber

A novel selectively metal-filled spiral photonic crystal fiber with an elliptic core is introduced and analyzed. The cladding air holes of the suggested design are arranged in spiral arms that are distributed in an elliptical form. In this paper, the dispersion characteristics and loss spectra of the reported design are studied through the full-vectorial finite-element method. The suggested design has advantages in terms of highly polarization-dependent coupling between x- and y-polarized core modes and higher order surface plasmon polariton (SPP) modes. It is evident from this study that the core modes can be separated from each other by changing the structure parameters. In addition, the resonance points at which the coupling between the core modes and SPP modes occurs can be tuned. Moreover, the coupling tunability of the proposed design can be increased by filling the cladding air hole with multiple metal wires. This novel structure is suitable for the design of filter-based applications. At wavelength λ = 1.013 μm, the loss of the x-polarized core mode is equal to 77.04 dB/mm, while it is only 2.765 dB/mm for the y-polarized core mode with single metal rod. However, for two metal rods, the losses for x- and y-polarized core modes are increased to 94.1 and 6.424 dB/mm, respectively, at λ = 0.98 μm.

Dispersion Characteristics of Asymmetric Channel Plasmon Polariton Waveguides

A novel asymmetric channel plasmon polaritons (CPPs) is proposed and analyzed. In this paper, the dispersion characteristics of asymmetric two and three-trenched CPPs structures are studied in detail. The suggested asymmetric structures have advantages in terms of propagation length and figure of merit over the symmetric CPP waveguides. In addition, a comparative study of various CPP metals including gold and silver is also presented. It is found that the propagation length and figure of merit of the silver-based structures are better than those of gold-based structures. In addition, the effect of bending on the asymmetric CPP waveguides is investigated. The simulation results are obtained by full-vectorial finite difference method with irregular meshing capabilities and perfectly matched layer boundary conditions.

Coupling Characteristic of a Novel Hybrid Long-Range Plasmonic Waveguide Including Bends

In this paper, the modal analysis of a novel design of a hybrid long-range plasmonic waveguide is introduced and analyzed using the full-vectorial finite difference method. The suggested design has high index material as a cap to reduce the propagation loss and optimum bending radius as well. The analyzed parameters are the real effective index and propagation loss. In addition, the bending analysis of the reported design is introduced. The coupling is performed between three different waveguides: straight dielectric waveguide, straight hybrid long-range plasmon waveguide, and uniformly bent hybrid one.

Optimized tapered dipole nanoantenna as efficient energy harvester.

In this paper, a novel design of tapered dipole nanoantenna is introduced and numerically analyzed for energy harvesting applications. The proposed design consists of three steps tapered dipole nanoantenna with rectangular shape. Full systematic analysis is carried out where the antenna impedance, return loss, harvesting efficiency and field confinement are calculated using 3D finite element frequency domain method (3D-FEFD). The structure geometrical parameters are optimized using particle swarm algorithm (PSO) to improve the harvesting efficiency and reduce the return loss at wavelength of 500 nm. A harvesting efficiency of 55.3% is achieved which is higher than that of conventional dipole counterpart by 29%. This enhancement is attributed to the high field confinement in the dipole gap as a result of multiple tips created in the nanoantenna design. Furthermore, the antenna input impedance is tuned to match a wide range of fabricated diode based upon the multi-resonance characteristic of the proposed structure.

Polarization-Independent Surface Plasmon Liquid Crystal Photonic Crystal Multiplexer–Demultiplexer

A novel design of polarization-independent surface plasmon multiplexer- demultiplexer (MUX/DEMUX) based on dual-core photonic crystal fiber with a central gold wire is proposed and analyzed. The cladding air holes are infiltrated with a nematic liquid crystal of type E7 with rotation angle φ, and the background material is a soft glass of type SF57 (lead silica). The simulation results are obtained using full-vectorial finite-difference method and coupled mode theory. At φ = 900, the suggested MUX/DEMUX has a short device length of 953.254 μm for x-polarized modes with broad bandwidths of 235 and 175 nm around wavelengths of 1.3 and 1.55 μm, respectively, with low cross-talk better than -20 dB. For y-polarized modes, the reported MUX/DEMUX has short device length of 1322.86 μm with broad bandwidths of 193 and 170 nm around 1.3 and 1.55 μm, respectively. Moreover, the polarization independence is achieved with short device lengths of 1138.06 and 1180 μm at φ = 90° and 0°, respectively.

Surface plasmon photonic crystal fiber biosensor for glucose monitoring

In this paper, design consideration of a surface plasmon photonic crystal fiber (PCF) biosensor for Glucose monitoring is presented and analyzed. Based on a well-known large mode area (LMA) PCF, two different configurations have been studied to investigate the effect of the etching process. The numerical results show that the plasmonic D-shaped PCF after etching three rows of air holes can achieve sensitivity of 200 nm/RIU with corresponding resolution of 1.3 ×10−3 RIU−1. The analysis is carried out using full vectorial finite element method (FVFEM) with perfect matched layer (PML) boundary conditions.

Optimization of nanoantenna for solar energy harvesting based on particle swarm technique

This paper presents a new trend in the design of nanoantenna for solar energy harvesting. By creating a link between a particle swarm optimization (PSO) algorithm and an external finite element frequency domain (FEFD) solver, the algorithm refines all the design metrics to optimize harvesting efficiency. Simulation results show the effectiveness of applying PSO to nanoantenna design which offers a total solar energy harvesting efficiency of 98.7%. This is significantly higher than up to date solar cells.