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Tuong P.V.,Hanyang University | Tuong P.V.,Vietnam Academy of Science and Technology | Park J.W.,Hanyang University | Rhee J.Y.,Sungkyunkwan University | And 4 more authors.
Applied Physics Letters | Year: 2013

We numerically and experimentally investigated dual-band absorption of sandwich-structure metamaterials which include periodic metal coupled rings at the front separated from the metal plane at the back by a dielectric layer. The properties are demonstrated in both GHz and mid-IR regimes of electromagnetic (EM) wave. The dual-band perfect absorber with polarization independence is observed under normal incidence. In order to understand the EM properties of dual-band perfect absorber, the plasmonic excitation was clarified for both peaks. Finally, by connecting the rings, the perfect-absorption peaks can be controlled with the polarization angle of incident EM wave. © 2013 American Institute of Physics.


Jin X.-R.,Hanyang University | Park J.,Hanyang University | Zheng H.,Hanyang University | Lee S.,Hanyang University | And 5 more authors.
Optics Express | Year: 2011

Using a planar metamaterial, which consists of two silver strips, we theoretically demonstrate the plasmonic electromagnetically-induced transparency (EIT)-like spectral response at optical frequencies. The two silver strips serve as the bright modes, and are excited strongly by the incident wave. Based on the weak hybridization between the two bright modes, a highly-dispersive plasmonic EIT-like spectral response appears in our scheme. Moreover, the group index is higher than that of another scheme which utilizes the strong coupling between the bright and dark modes. © 2011 Optical Society of America.


Yoo Y.J.,Hanyang University | Kim Y.J.,Hanyang University | Van Tuong P.,Hanyang University | Rhee J.Y.,Sungkyunkwan University | And 5 more authors.
Optics Express | Year: 2013

We propose a dual-band metamaterial perfect absorber at microwave frequencies. Using a planar metamaterial, which consists of periodic metallic donut-shape meta-Atoms at the front separated from the metallic plane at the back by a dielectric layer, we demonstrate the multiplasmonic high-frequency perfect absorptions induced by the thirdharmonic as well as the fundamental magnetic resonances. The origin of the induced multi-plasmonic perfect absorption was elucidated. It was also found that the perfect absorptions at dual peaks are persistent with varying polarization.©2013 Optical Society of America. © 2013 Optical Society of America.


Zheng H.Y.,Hanyang University | Jin X.R.,Yanbian University | Park J.W.,Hanyang University | Lu Y.H.,Ningbo Institute of Materials Technology and Engineering | And 4 more authors.
Optics Express | Year: 2012

Magnetic resonance is considered to be a necessary condition for metamaterial perfect absorbers, and dual-band absorbers can be composed of a pair of metallic layers with anti-parallel surface currents. We designed and fabricated a tunable dual-band perfect absorber based on extraordinaryoptical- transmission (EOT) effect and Fabry-Perot cavity resonance. The idea and the mechanism are completely different from the absorber based on the near-field interaction. The important advantage of our structure is that we can switch a single-band absorber to a dual-band absorber by changing the distance between two metallic layers and/or incident angle. The peak originating from the EOT effect becomes significantly narrower, resulting in an increase of the Q-factor from 16.88 to 49. The dual-band absorber can be optimized to be insensitive to the polarization of the incident electromagnetic wave by slightly modifying the absorber structure. © 2012 Optical Society of America.


Tuong P.V.,Hanyang University | Tuong P.V.,Vietnam Academy of Science and Technology | Park J.W.,Hanyang University | Lam V.D.,Vietnam Academy of Science and Technology | And 4 more authors.
Computational Materials Science | Year: 2012

We investigated the dependence of reflectance and absorbance of a metamaterial structure (consisting of unit cells with two metallic parts, an electric ring resonator (ERR) at the front and a cut-wire bar at the back, separated by a dielectric layer) on gap 'g' of the structure at GHz frequencies. Our simulation results have shown that, by increasing the gap, the maximum absorbance and the minimum reflectance were obtained to be 94.42 and 0.74%, respectively, at 12.3 GHz. It was significant that the geometry of ERR was changed as an I-shape to observe a narrow-band peak of the perfect-absorber effect, whose absorbance was enhanced to be greater than 99.5% at 13.5 GHz by using a multilayer model for the simplified absorber structure. © 2012 Elsevier B.V. All rights reserved.


Park J.W.,Hanyang University | Tuong P.V.,Hanyang University | Rhee J.Y.,Sungkyunkwan University | Kim K.W.,Sun Moon University | And 4 more authors.
Optics Express | Year: 2013

We propose multi-band metamaterial absorbers at microwave frequencies. The design, the analysis, the fabrication, and the measurement of the absorbers working in multiple bands are presented. The numerical simulations and the experiments in the microwave anechoic chamber were performed. The metamaterial absorbers consist of an delicate arrangement of donut-shape resonators with different sizes and a metallic background plane, separated by a dielectric. The near-perfect absorptions of dual, triple and quad peaks are persistent with polarization independence, and the effect of angle of incidence for both TE and TM modes was also elucidated. It was also found that the multiple-reflection theory was not suitable for explaining the absorption mechanism of our investigated structures. The results of this study are promising for the practical applications. © 2013 Optical Society of America.


Lee Y.P.,Hanyang University | Tuong P.V.,Hanyang University | Zheng H.Y.,Hanyang University | Rhee J.Y.,Sungkyunkwan University | Jang W.H.,Electromagnetic Wave Institute
Journal of the Korean Physical Society | Year: 2012

We studied structures that describe the perfect-absorber effect by using different mechanisms. Firstly, we investigated the dependences of the reflectance and the absorbance of a metamaterial, as structure proposed by Landy et al. [Phys. Rev. Lett. 100, 207402 (2008)] on gap 'g' of the structure at GHz frequencies. The value of the gap was obtained, which gives the maximum absorbance and the minimum reflectance. In addition, the change of geometry of the electric ring resonance as an I-shape made the reflectance disappear at the resonance frequency. A narrow-band peak of the perfect-absorber effect, which was enhanced to be greater than 99.5% at 13.5 GHz, was observed by using a multilayer model for the simplified absorber structure. Secondly, we investigated an absorber structure that includes two metal layers, periodic cut-wire bars at the front and a copper plane at the back, separated by a dielectric layer. The results showed that the absorbance and the resonance frequency of this structure strongly depended on the thickness and the length of the cut-wire bar, respectively. Base on these, we successfully designed a broad-band absorber structure by arranging cut-wire bars with different lengths appropriately in a "meta-atom".


Jin X.-R.,Hanyang University | Lu Y.,Hanyang University | Lu Y.,Ningbo Institute of Materials Technology and Engineering | Zheng H.,Hanyang University | And 4 more authors.
Optics Communications | Year: 2011

Using only two gold strips, we propose a scheme for generation of the plasmonic analogue of electromagnetically-induced transparency (EIT) in stacked optical metamaterials by utilizing the second-order plasmon resonance. In addition, we show that the plasmonic EIT can be achieved with asymmetric structure, since the asymmetric structure allows the excitation of the dark mode. © 2011 Elsevier B.V.


Tuong P.V.,Hanyang University | Park J.W.,Hanyang University | Lam V.D.,Vietnam Academy of Science and Technology | Jang W.H.,Electromagnetic Wave Institute | And 3 more authors.
Journal of Lightwave Technology | Year: 2012

We numerically and experimentally investigated the negative refractive index effect in a single subwavelength magnetic meta-atom, a flower-shaped metamaterial (MM) structure. In our effort to understand the electromagnetic properties of flower-shaped structure, the third resonance has been considered for a rather high frequency in the gigahertz range of electromagnetic wave. It is found that the negative refractive index is a result of the tail of electric gap and the magnetic resonance at the third-order resonance. The effect is switched OFF by adjusting the density of flowers. In addition, the negative refractive index behavior is accompanied by polarization insensitivity resulting from its geometry. Finally, the electromagnetic and the loss properties of the MM were clarified at the third-order gap. © 1983-2012 IEEE.


Tuong P.V.,Hanyang University | Tuong P.V.,Vietnam Academy of Science and Technology | Park J.W.,Hanyang University | Lam V.D.,Vietnam Academy of Science and Technology | And 3 more authors.
Optics Communications | Year: 2013

We investigated two mechanisms of the heat generation to enhance the absorption peak of metamaterials (MMs) at the normal incidence of electromagnetic radiation. The metal-dielectric-metal sandwich-type model, in which an array of copper squares at the front and a copper plane at the back were separated by a dielectric layer, was studied for GHz frequencies. Firstly, we studied the effect of the thickness of copper square to obtain the absorption peak. The obtained results showed that absorption can be enhanced to be nearly 100% at 16 GHz by increasing the sheet resistance of the copper square. In this case, the Ohmic-loss perfect-absorption (PA) MM was devised. The PA effect was also achieved by using the loss-tangent of dielectric layer as a dissipation factor. For this purpose, we studied complex the dielectric constant of dielectric layer. The PA peak was demonstrated at the same frequency. In the second case, the dielectric-loss turns out to be dominant. The comparison between TE and TM polarizations for the PA peaks was also elucidated. © 2013 Elsevier B.V.

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