Gui Qiang Liu

A New Plasmonic Filter through Double Metal Films Perforated with Rectangular Grooves and Circular Holes

A novel plasmonic passband filter consisting of metal-insulator-metal perforated with an array of rectangular grooves and circular holes is proposed and demonstrated. The transmission property of the proposed structure is obtained by employing the finite difference time domain with perfectly matched layer absorbing boundary condition. The result reveals that a passband with high transmission can be achieved. And the transmission peak position can be efficiently tuned by changing the factors of the structure, such as the sizes of circular holes and grooves. The proposed filter has potential applications for integrated optoelectronic devices due to its miniaturized size.

Optical Properties of Two Malposed Silver Triangular Nanocylinder Arrays

We propose and theoretically study a novel plasmonic nanostructure composed of two malposed silver (Ag) triangular nanocylinder arrays by the finite-difference time-domain (FDTD) method. The excitation of the localized surface plasmons (LSPs) of the metal triangular nanocylinders, and the strong interaction coupling between LSPs contribute to the enhanced transparency in the visible and near-in region (NIR). The transparency response in the proposed nanostructure is modified by changing the gap distances between two adjacent triangular nanocylinders, and the dielectric environments. The tunable enhanced optical transparency of the proposed nanostructure provides potential applications in sensors and plasmonic filters.

Metallic Ellipsoidal Array – Film for Enhancing Transmission via Plasmonic Coupling

In this paper, a novel metal structure that integrates double continuous Au films and double aligned gold (Au) non-close-packed ellipsoidal nanoparticle arrays is proposed. The optical features of this structure are simulated by using the three-dimensional finite-difference time-domain (3D-FDTD) method. Bimodal plasmonic resonances with the highest transmission up to 74% and 66% (corresponding to the short and long-wavelength, respectively) are achieved. This proposed structure with sub-wavelength size may provide fascinating applications in optoelectronic devices such as transparent conductors and conductive devices, slow light devices, highly sensitive sensors.

Near-Field Broadband Light Transparency via Tunneling and Cavity Effects

This work presents a broadband optical transparency structure consisting of a metal film perforated by an array of strip cavities. We theoretically demonstrate the metal film with side-coupled grooves system in model structure by the coupled model theory. The transparent light with a great bandwidth is obtained as a result of the tunneling and the resonance effect of the cavities by employing the finite-difference time-domain method simulation. By changing the parameter of the grooves in the structure, the transparency property shows a great adjustment in both wavelength and bandwidth. These structures have potential applications for transparent conductor devices.

Optical Transparent Behaviors of Double Plasmonic Arrays Sandwiched with a Metal Film

We propose a high tunable plasmon-induced transparency metal film structure which can be performed by double two-dimensional hexagonal lattice array of plasmonic nanoparticles inserted with a continuous metal film. The structure shows metal transparency in the optical regime. The transparency response in this structure can be efficiently modified by varying the thickness of the metal film, the size of nanoparticles, and the position of the nanoparticles. The structure proposed here may provide a new alternative approach to obtain transparent and highly conducting metal structures with potential applications in optoelectronic integrated circuits, plasmonic filters and transparent conductors.

A New Two-Sided Coupling Channel Drop Filter Based on a Two-Dimensional Photonic Crystal

We design a new two-sided coupling channel drop filter (CDF) based on a two-dimensional (2D) photonic crystal (PC). Three channels formed by line defects for light propagation, two L4 resonators positioned at both sides of the input waveguide for light coupling, and one point defect micro-cavity in the bus waveguide for wavelength-selective reflection are introduced into the PC structure. The optical characteristics of this proposed structure are calculated by finite-difference time-domain (FDTD) method combined with the perfectly matched layers (PMLs) as the boundary conditions. Three wavelengths centered at 1550, 1575 and 1610 nm within the limit of communication windows are successfully separated in three channels by adjusting the size of coupling rods and the positions of L4 resonators and micro-cavity. High transmission efficiency and more than 20 nm channel spacing are achieved. These demonstrate that our proposed structure is suitable for photonic integrated circuits (PICs) and coarse wavelength division multiplexing (WDM) optical communication systems.

Fabrication of 3D Photonic Crystals of Non-Magnetic Ellipsoids with Different Aspect Ratio

This paper introduces a method of preparation of photonic crystals with non-magnetic ellipsoid as building blocks. Under the condition of above its glass-transition temperature, monodispersed polystyrene (PS) spheres with the diameter of 260 nm and 360 nm were respectively elastic stretched by applying external force with different values to get different ellipsoids with different aspect ratios. The assembly procedure was carried out by applying the vertical deposition self-assembly method in a magnetic field under the guidance of magnetic fluids. In this paper, We report the crystalline structure with long range order.

A New Two-Dimensional Photonic Crystal Channel Drop Filter Based on Two-Resonant Cavities

In this paper, a channel drop filter (CDF) is composed of two cubic lattice circular ring resonator cavities and point micro-cavities in a two-dimensional photonic crystal. The photonic band gap is calculated using the plane wave expansion (PWE) method and the optical characteristics of proposed structure are studying by the finite difference time domain (FDTD) method with perfectly matched layers (PMLs) acting as the boundary conditions . Two different wavelengths centered at 1773 nm and 1742 nm have been successful separation in this CDF. These demonstrate that our proposed structure is suitable for photonic integrated circuits (PICs) and coarse wavelength division multiplexing (WDM) optical communication systems.