Metamaterial Covers Over a Small Aperture

Alù, Andrea; Bilotti, Filiberto; Engheta, Nader; Vegni, Lucio

doi:10.1109/tap.2006.875470

Cited by 111 publications

(62 citation statements)

References 35 publications

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“…Extraordinary light transmission has been extensively studied by using subwavelength periodic hole arrays [3][4][5][6][7] or metallic structures with a single aperture [7][8][9][10][11][12]. Based on Bethe's theoretical description, transmission through a single subwavelength aperture of a radius r << λ scales with (r/λ) 4 [13].…”

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confidence: 99%

Split-Ring-Resonator-Coupled Enhanced Transmission through a Single Subwavelength Aperture

et al. 2009

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We report the enhanced transmission of electromagnetic waves through a single subwavelength aperture by making use of the resonance behavior of a split ring resonator (SRR) at microwave frequencies. By placing a single SRR at the near-field of the aperture, strongly localized electromagnetic fields are effectively coupled to the aperture with a radius that is twenty times smaller than the resonance wavelength (r/λ = 0.05). We obtained 740-fold transmission enhancement by exciting the electric resonance of SRR. A different coupling mechanism, through the magnetic resonance of SRR, is also verified to yield enhanced transmission. Good agreement is obtained between the microwave measurements and numerical simulations.

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confidence: 99%

Split-Ring-Resonator-Coupled Enhanced Transmission through a Single Subwavelength Aperture

et al. 2009

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“…6,7 Methods have been sought to effectively guide the incoming electromagnetic ͑EM͒ wave into the subwavelength aperture that will in return result in enhanced transmission. A slightly different approach was adapted in a paper by Alu et al, 8 in which a matematerial cover over the aperture was theoretically shown to produce enhanced directional transmission by minimizing the diffraction losses. On the other hand, split ring resonators ͑SRRs͒ had already gained a well-established background in the metamaterial community.…”

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confidence: 99%

Enhanced transmission through a subwavelength aperture using metamaterials

Cakmak

Aydın

Çolak

et al. 2009

Applied Physics Letters

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We report an enhanced transmission through a single circular subwavelength aperture that is incorporated with a split ring resonator ͑SRR͒ at the microwave regime. Transmission enhancement factors as high as 530 were observed in the experiments when the SRR was located in front of the aperture in order to efficiently couple the electric field component of the incident electromagnetic wave at SRR's electrical resonance frequency. The experimental results were supported by numerical analyses. The physical origin of the transmission enhancement phenomenon was discussed by examining the induced surface currents on the structures. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3195074͔The interest in transmission through subwavelength apertures has recently rapidly increased. 1,2 The topic was addressed during the 1940s, where Bethe 3 put forward his theoretical analysis suggesting relatively poor transmission figures at the output side of a subwavelength aperture. The problem remained a major challenge until the pioneering work of Ebbesen et al. 4 From that moment on, the main focus has been shifted to elucidate the enhancement mechanism for subwavelength apertures. 5 Researchers have set out to identify the role of the surface plasmons and to offer physical explanations for the transmission enhancement phenomenon. 6,7 Methods have been sought to effectively guide the incoming electromagnetic ͑EM͒ wave into the subwavelength aperture that will in return result in enhanced transmission. A slightly different approach was adapted in a paper by Alu et al.,8 in which a matematerial cover over the aperture was theoretically shown to produce enhanced directional transmission by minimizing the diffraction losses. On the other hand, split ring resonators ͑SRRs͒ had already gained a well-established background in the metamaterial community. 9 Innovative models were developed for SRRs that were placed inside a small circular metallic aperture. 10 Subsequently, Aydin et al. 11 proposed in a rather recent work an alternative method for transmission enhancement by putting a SRR in front of a subwavelength aperture.We present here a more detailed analysis of the enhanced transmission process by focusing on an electrically coupled SRR that was made to cooperate with a subwavelength aperture. The resonator nature of the SRR was exploited to concentrate the fields in the vicinity of a subwavelength aperture to facilitate considerable improvement in the transmission factors at microwave frequencies. Besides, the dependence of the resonance frequency of the SRRs on the enhanced transmission was studied by employing three different SRRs in the simulations and experiments. Induced surface currents were calculated in order to discuss the enhancement mechanism. The transmission improvement figures were obtained as a function of various aperture radii.Three distinct SRR designs with the labeled dimensions, which are shown in Fig. 1͑a͒, were used. SRRs are deposited on a dielectric printed circuit board ͑PCB͒ with a thickness of 1.6 ...

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“…Instead of the electrically large cover suggested by Alu et al in Ref. [11], we make use of the resonance mechanism of a single negative material as pointed out in Ref. [12].…”

Section: Transmission Enhancement Phenomenonmentioning

confidence: 99%

“…The corrugated surfaces increased the transmission and provided better coupling conditions. Alternatively, Alu et al suggested covering the aperture with a metamaterial slab in order to achieve superior coupling efficiencies [11]. On the other hand, Bilotti et al proposed exploiting the resonance characteristics of the metamaterials, which in turn yielded the amplification of the electromagnetic fields around the aperture [12].…”

Section: Introductionmentioning

confidence: 99%

Near-field light localization using subwavelength apertures incorporated with metamaterials

Ates

Cakmak

Özbay

2012

Optics Communications

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We report strong near-field electromagnetic localization by using subwavelength apertures and metamaterials that operate at microwave frequencies. We designed split ring resonators with distinct configurations in order to obtain extraordinary transmission results. Furthermore, we analyzed the field localization and focusing characteristics of the transmitted evanescent waves. The employed metamaterial configurations yielded an improvement on the transmission efficiency on the order of 27 dB and 50 dB for the deep subwavelength apertures. The metamaterial loaded apertures are considered as a total system that offered spot size conversion ratios as high as 7.12 and 9.11 for the corresponding metamaterial configurations. The proposed system is shown to intensify the electric fields of the source located in the near-field. It also narrows down the electromagnetic waves such that a full width at half maximum value of λ/29 is obtained.

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Metamaterial Covers Over a Small Aperture

Cited by 111 publications

References 35 publications

Split-Ring-Resonator-Coupled Enhanced Transmission through a Single Subwavelength Aperture

Split-Ring-Resonator-Coupled Enhanced Transmission through a Single Subwavelength Aperture

Enhanced transmission through a subwavelength aperture using metamaterials

Near-field light localization using subwavelength apertures incorporated with metamaterials

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