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Metamaterials and negative index materials VI

14:00 : Near-zero refractive index metamaterials boost graphene-polymer heterostructures absorbers in GHz regime

Michael Lobet, Luc Henrard, Philippe Lambin

University of Namur (Belgium)

Graphene-polymer heterostructures have recently been shown to efficiently absorb GHz electromagnetic radiation up to ~ 50 percent. We demonstrate that those structures are robust to fabrication process defects (microscopic holes, microscopic embryos of second layer or grain boundaries). Moreover, using near-zero refractive index metamaterial as a substrate, the device tends towards perfect absorption. Absorption is consequently enhanced from 41.8 percent to 87.5 percent using a near-zero epsilon as a substrate.
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14:15 : Spontaneous emission in metal-dielectric metamaterials including losses

Azat Gubaydullin, Mikhail Kaliteevski

St Petersburg Academic University (Russia)

We study the emission rate enhancement of the dipole emitter centered in the stratified metal-dielectric metamaterial, characterized by the hyperbolic isofrequency surfaces. We find out a limited enhancement of the Purcell factor in the layered metamaterial. We demonstrate that the radiative decay rate is strongly depends on a ratio of the thickness of layers and is affected by the level of losses.
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14:30 : Aperiodic metallic gratings transparent for broadband electromagnetic waves

Ru-Wen Peng, Xiao-Ping Ren, Ren-Hao Fan, Mu Wang

Nanjing University (China)

In this work, we demonstrate both theoretically and experimentally that aperiodic metallic gratings can become transparent for broadband electromagnetic waves. It is shown that broadband high transmission appears in aperiodic metallic gratings (including quasi-periodic and disordered ones), which originates from the non-resonant excitations in the grating system. An optimal condition is also achieved for broadband high transparency in the grating system. The findings can be applied for transparent conducting panels, perfect white-beam polarizers, antireflective conducting solar cells, and beyond.
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14:45 : Metamaterial Inspired Multiband Antenna at UHF Band

N. A. Borhan, N. A. Murad, M. K. A. Rahim

Universiti Teknologi Malaysia (Malaysia)

In this paper, metamaterial based multiband antenna is proposed. The antenna consists of four units of double split ring resonator (DSRR) and a planar fed straight line monopole. The combination of the DSRRs and the monopole enable the resonance frequency at Ultra High Frequency (UHF) band which are 0.52 GHz, 0.54 GHz, 0.63 GHz, 0.65 GHz and 0.75 GHz for the multiple band operation. Simulation results are presented and discussed.
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15:00 : A Wavelength-Sized Filter and THz Spectrometer Based on Bound Resonances of a Slotted Waveguide

Meredith A. Henstridge, Jing Zhou, L. Jay Guo, Roberto Merlin

University of Michigan (USA)

We discuss a structure consisting of two parallel copper plates bisected by subwavelength slits, which exhibits long lived Fabry Perot like resonances bound to the slits at THz frequencies. Using THz time-domain spectroscopy (THz-TDS), we measured the transmission of a focused pulse through the slotted plates. Results show good agreement with simulations. The scalability, tunability, and high quality factors of the resonances make the slotted plates a promising candidate for narrowband filtering and spectroscopic applications.
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15:15 : Near infrared photon trapping in amorphous HgCdTe metamaterials

Young U. Jung (1),Igor Bendoym (2),David Crouse (1)

(1)City College of New York (USA) , (2)Phoebus Optoelectronics LLC (USA)

Recently, amorphous HgCdTe films have been extensively studied for various spectral detection applications due to their interesting properties. Such properties include film deposition on any substrate, direct growth on device and higher operating temperatures with the low dark current. In this work, we investigate the photon trapping in amorphous HgCdTe metamaterial detectors that confines the light near the surface of the detecting materials and consequently reduces the thickness of the semiconducting layer with the low dark current.
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15:30 : Metamaterial Perfect Absorber Based Hot Electron Photodetection

Wei Li, Zachary Coppens, Jason Valentine

Vanderbilt University (USA)

We demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how this approach can be used to realize highly selective detection of circularly polarized light.
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15:45 : Wideband Polarization Insensitive Metamaterial Absorber with Perfect Dual Resonances.

Osman Ayop, M. K. A. Rahim, N. A. Murad, N. A. Samsuri

Universiti Teknologi Malaysia (Malaysia)

This paper presents the analysis of wideband polarization insensitive metamaterial absorber with perfect dual resonances. The structure is designed using lossy FR4 substrate with copper layers. The resonating elements are designed using the combination of circular ring with modified circular structure. From the simulation, the proposed design achieves nearly perfect absorption at 9.81 GHz and 10.41 GHz with absorbance bandwidth of 10.29 percent. From observation, the structure can maintain the absorbance characteristic for all polarization angle.
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