Electromagnetic resonances of a multilayer metal-dielectric stack

Gadsdon, M. R.; Parsons, J.; Sambles, J. R.

doi:10.1364/josab.26.000734

Cited by 19 publications

(22 citation statements)

References 14 publications

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“…2͒ occur when sine-or cosine-like standing-waves in the dielectric layers couple via exponential fields within the metamaterial layers. Our experimental geometry is similar to that recently studied analytically by Gadsdon et al 16 who considered alternating layers of untextured metal and dielectric films in the visible regime. They showed that the metal film acts as a tunnel barrier, with the fields within the metal films taking either a hyperbolic sine or hyperbolic cosine form.…”

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confidence: 56%

“…Importantly, this field solution is unlike that for an all dielectric multilayer stack. 5 ͑Note that the hyperbolic parts of the field distribution do not occur symmetrically in the second and fourth metamaterial layers due to the impedance mismatch with free space at the top and bottom of the stack.͒ The consequence of this result is particularly striking when one considers the effect of an increase of the number of repeat units in the stack 16 from four to ten ͑see Fig. 4͒: the lowest frequency mode ͑A͒ does not significantly move.…”

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confidence: 99%

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Microwave transmissivity of a metamaterial–dielectric stack

Butler

Parsons

Sambles

et al. 2009

Applied Physics Letters

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A metamaterial layer comprising of a conducting square mesh surrounding subwavelength holes has a largely pure imaginary effective refractive index. We explore the microwave transmissivity of a stack of such metamaterial layers separated by dielectric spacers. As expected, a family of high transmissivity bands is experimentally observed. It is found that the lowest frequency edge is independent of the number of unit cells making up the structure and is highly tunable by appropriate geometrical design of the metamaterial layers. © 2009 American Institute of Physics. ͓doi:10.1063/1.3253703͔Multilayer metal-dielectric structures have been extensively studied at visible frequencies, and their response utilized in areas such as electromagnetic shielding, nonlinear photonics and perfect lensing.1-3 Geffcken 4 in 1939 fabricated metal-dielectric thin film stacks that exhibited transmission features that were significantly narrower than those previously observed in conventional dielectric-dielectric multilayer arrangements. 5The spectral response of metal-dielectric stacks in the visible regime comprises of a series of photonic band gaps where the reflectivity is high ͑and the transmissivity is low͒, separated by a series of peaks of high transmissivity. These transmission peaks correspond to near-standing-wave resonances within each dielectric cavity, coupled together via exponential fields within the metal film. Near the high frequency band edge of the first transmission band, the electric fields are predominantly confined to the dielectric and pass through zero in the metal. In contrast, at the low frequency band edge a significant proportion of the field enhancement occurs inside the metal regions. [6][7][8] An equivalent study of a metal-dielectric layer stack in the microwave domain ͑10 9 -10 10 Hz͒ is at first sight impractical since the real and imaginary parts of the refractive index of metals are both large ͑Ͼ10 3 ͒ and almost equal ͑i.e., the metal is near-perfectly conducting͒. Even a metal film of thickness 20 nm will almost completely screen the incident field 9 because of the large impedance mismatch. Instead, a metal is structured on the subwavelength scale to create a metamaterial with effective electromagnetic properties which replicates the behavior of Drude-like ͑plasmonic͒ metals in the visible regime ͑Ag, Au, etc.͒. 10 The metamaterial layer consists of a non diffracting square metal mesh surrounding an array of identical square holes. At wavelengths greater than the size of the holes, the electromagnetic fields are exponential within the holes with a decay length that is primarily dictated by the metamaterial geometry. Consequently the metamaterial is equivalent to a thin layer with a pure imaginary refractive index. 12,13The sample shown in Fig. 1͑a͒ comprises of eight printed circuit board ͑PCB͒ layers that are originally clad with 18 m of copper on one face. The copper is removed from three of these substrates the remaining five being etched to leave a copper square mesh ͑Fig. 1͑b͒͒ with period...

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confidence: 56%

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confidence: 99%

Microwave transmissivity of a metamaterial–dielectric stack

Butler

Parsons

Sambles

et al. 2009

Applied Physics Letters

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“…It has been demonstrated that, near either band edge, there is a large enhancement of the field intensity due to localization effects [10,11]. Near the high-frequency band edge of the lowest frequency bandpass region, the electromagnetic field is predominantly confined to the dielectric regions in a manner similar to a stack of Fabry-Perot cavities, while at the low-frequency band edge, the fields are more concentrated in the metal regions [10,12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, we have explained the formation of the bandpass regions as being due to the matching of the tangential electric and magnetic fields associated with standing cavity modes in the dielectric, which may have either a cos or a sin wave character, and evanescent standing modes in the metal, which may have either a cosh or a sinh distribution function [10].…”

Section: Introductionmentioning

confidence: 99%

Surface plasmon polaritons on deep, narrow-ridged rectangular gratings

et al. 2009

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The dispersion diagrams of surface plasmon polaritons have been calculated for rectangular gratings, with very narrow wires, of varying depths. For gratings with a moderate height a family of vertical-standing-wave resonances may be excited, which consist of surface plasmons, oscillating on either vertical surface, coupling together through the metal wires. These modes evolve similarly to the manner in which shallow-grating surface-plasmon dispersion curves evolve into cavity modes in the grooves of the structure. However, on further increase in grating height these vertical standing waves evolve into a second resonant feature, which is independent of yet further increases in height. This new mode is shown to be equivalent to the resonances found on infinite multilayer metal/dielectric structures illuminated at normal incidence.

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“…With the latest developments in fabrication technology, the transmission and reflection spectra of these structures can be realized at optical, [1][2][3][4] infrared, 5,6 terahertz, [7][8][9] and microwave [10][11][12][13] frequencies through careful design of the constituent subwavelength periodic elements and dielectric layers. For example, these include a stack of metal apertures (mesh-grids) at microwave 12 and infrared frequencies, 5,6 a stack of metallic patch arrays at microwave frequencies, 13 metal-dielectric and aperture/mesh-grid-dielectric stacks at optical frequencies, [1][2][3][4] and more recently a stack of graphene sheets-dielectric layers at low-terahertz frequencies. 9 Various periodically patterned graphene surfaces [14][15][16][17][18] have been designed at microwave, terahertz, and optical frequencies for tunable metamaterials, with potential applications including filters, absorbers, and polarizers.…”

Section: Introductionmentioning

confidence: 99%

Dual capacitive-inductive nature of periodic graphene patches: Transmission characteristics at low-terahertz frequencies

et al. 2013

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We report on the dual nature (capacitive and inductive) of the surface impedance of periodic graphene patches at low-terahertz frequencies. The transmission spectra of a graphene-dielectric stack shows that patterned graphene exhibits both the low-frequency (capacitive) passband of metal patch arrays and the higher-frequency (inductive) passband of metal aperture arrays in a single tunable configuration. The analysis is carried out using a transfer-matrix approach with two-sided impedance boundary conditions, and the results are verified using full-wave numerical simulations. In addition, the Bloch-wave analysis of the corresponding infinite periodic structure is presented in order to explain the passband and stopband characteristics of the finite graphene-dielectric stack.

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Electromagnetic resonances of a multilayer metal-dielectric stack

Cited by 19 publications

References 14 publications

Microwave transmissivity of a metamaterial–dielectric stack

Microwave transmissivity of a metamaterial–dielectric stack

Surface plasmon polaritons on deep, narrow-ridged rectangular gratings

Dual capacitive-inductive nature of periodic graphene patches: Transmission characteristics at low-terahertz frequencies

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