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We proposed a novel quad-wavelength multi-focusing lens, in which four focusing spots could be arbitrarily controlled at four frequencies independently. A prototype quad-wavelength lens has been designed and numerically verified at terahertz frequencies.
We investigate optical nanoantennas featuring asymmetrical stepped-junction structures. By breaking the symmetry of the conventional optical nanoantennas, the performance of them is improved in many aspects. Experiments have been conducted to validate the proposed design.
This paper presents a novel design of tunable terahertz devices using graphene parallel-plate waveguide (GPPWG). Graphene parallel-plate waveguide can provide tunable propagation constant which can be controlled by the external biasing voltage. To facilitate the design, closed-form design equations are derived. Based on the proposed GPPWG, tunable devices can be designed in the terahertz (THz) range...
The capability to manipulate the polarization state of electromagnetic waves and light is important in optical systems. Metamaterial (MM) as an alternative to manipulate the wave polarization state have drawn considerable attention due to its attractive characteristics, such as near zero refractive index, cloaking, etc. Thus a number of electromagnetic wave polarizer and wave plate have been realized...
Two types of cross polarization converters (CPCs) that can simultaneously work at several wavelengths in the reflection mode in near infrared spectrum range are proposed. The first type (type I) is constructed of an L-shaped perforated silver layer (top layer) printed on a dielectric material backed by a gold ground plane, which can work at three frequencies due to the excitation of three different...
In this paper, the state-of-the-art quasi-conformal mapping (QCM) transformation optics technique is studied to design high performance electromagnetic devices which can be widely applied in the fields of microwaves and optics. At first, novel plasmonic wave manipulator is designed, which can manipulate the transmission of plasmonic waves efficiently. Second, a 3D microwave flattened parabolic antenna...
We present a refractive index engineering scheme for functional metal oxides (SnO2, ZnO, TiO2) by the method of sub-wavelength engineering on the 10-50nm scale for applications in optical sensing. The method employed is based on templating by a triblock copolymer Pluronic F-127 for the manufacture of controllable 3D sub-wavelength nanostructures. By this method we demonstrate that the refractive indices...
In this paper, graphene-based optical antennas with reconfigurable responses will be studied. The proposed nano-antenna is originated from a broadband optical antenna. The proposed devices will be able to provide reconfigurable performance by exploiting the tuning property of graphene. Optical antenna is one of the most important optical nano-devices. Similar to the radio-frequency and microwave antennas,...
In this paper, broadband metasurfaces with the capability to manipulate electromagnetic waves with arbitrary polarizations are studied. Various types of metasurfaces with different geometries will be investigated. The proposed devices will be able to provide the same performance under different polarizations. Metasurface is known as metamaterials surface with ultra-thin thickness (i.e. much smaller...
Novel design of tunable THz plasmonic devices based on liquid metals is presented in this paper. The designed devices will be able to dynamically control and change the spectrum responses of THz signals. An equivalent circuit model has also been developed to describe the operating principle of the proposed THz devices. Good agreement has been achieved between the theoretical models and the numerical...
Curved lenses and antennas have pivotal meaning in various applications. For example, gradient index lenses such as the Luneburg lens are used to realize perfect imaging. However, the procedure of fabricating the bended surface of these lenses and antennas is difficult and not cost effective. In order to solve this issue, in this paper, we propose to apply transformation optics techniques to re-design...
In this paper, we propose the design of a reconfigurable surface plasmon polariton (SPP) wave adapter designed by transformation optics, which can control the confinement of SPP waves on un-even metal surfaces. The proposed plasmonic device is constructed using homogeneously tunable materials (i.e. liquid crystals) so that the corresponding SPP wave transmission can be reconfigured by applying different...
We report a waveguide gap structure for nonlinear coupling, written in chalcognide glass with an ultrafast laser. The coupling efficiency between two waveguides is enhanced by the self focusing of shorter and stronger input pulse.
This paper presents a laser-assisted chemical vapor deposition of silicon thin film and silicon thin film long-period gratings inside a two-hole fiber and photonic crystal fiber with hollow cores.
In this paper, we report the development of an integrated two-layer phase mask for five-beam holographic fabrication of three-dimensional photonic crystal templates.
Penrose-type photonic quasi-periodic crystals are fabricated through 5 or 6 beam holographic lithography using a lab-made phase mask. The quasi-crystal structure is confirmed through diffraction patterns showing ten-fold symmetry.
This paper presents the holographic fabrication of three-dimensional photonic crystal templates by forming a five beam interference pattern using a top-cut prism. The interconnecting of the multi-layer structures was controlled by phase-tuning one interfering beam.
In this paper, we report a new design and fabrication of an integrated two-layer phase mask for five-beam holographic fabrication of three-dimensional photonic crystal templates.
Face-centered-orthorhombic and face-centered-tetragonal woodpile-type photonic crystal templates have been fabricated with laser phase mask holographic lithography. Photonic band gap calculation predicts the existence of full band gap in those crystals.
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