Comparison of density of states and scattering parameters in coaxial photonic crystals: Theory and experiment

Khattou, Soufyane; Amrani, Madiha; Mouadili, A.; Boudouti, El Houssaine El; Talbi, Abdelkrim; Akjouj, Abdellatif; Djafari‐Rouhani, Bahram

doi:10.1103/physrevb.102.165310

Cited by 18 publications

(12 citation statements)

References 70 publications

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“…The analysis and exploitation of the delay times are useful for the characterization of the resonances and BICs, as reported here. The correspondences between DOS and delay times are similar to those reported recently by some of our group in photonic coaxial cables [48].…”

Section: Triple Solid-liquid-solid Layersupporting

confidence: 88%

Experimental Evidence of the Existence of Bound States in the Continuum and Fano Resonances in Solid-Liquid Layered Media

Amrani¹,

Quotane²,

Ghouila-Houri

et al. 2021

Phys. Rev. Applied

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Bound states in continuum (BICs) are resonances with zero width (infinite lifetime) without any leakage into the surrounding media. Their fascinating properties and potential applications have attracted a great deal of interest. In this paper, we give an analytical, numerical, and experimental demonstration of BICs in simple acoustic structures based on either a single solid layer or a triple solid-liquid-solid layer inserted between two liquids. These modes are an intrinsic property of the inserted structure (solid layer or solidliquid-solid triple layer) with free surfaces and are independent of the surrounding media. Two kinds of BICs are discussed: (i) Fabry-Perot (FP) BICs exist as the consequence of the intersection of the local resonances induced by inserted structure intersect the transmission zeros induced by the solid layers. (ii) Symmetry-protected (SP) BICs occur when appear at normal incidence due to the decoupling of the transverse modes in the solid layer from the longitudinal modes that propagate in the solid and solidliquid multilayer media. When the incidence angle departs slightly from the BIC conditions, the latter transform into Fano resonances characterized by an asymmetric line shape in the transmission spectra. In addition, we show that the transmission zeros give rise to negative delay times and therefore acoustic superluminal effect. The theoretical results are obtained by means of the Green's function method, whereas the experimental measurements are carried out in ultrasonic domain using plexiglass plates in water. These results may have important applications to realize subsonic and acoustic superluminal phenomena as well as acoustic filters and sensors.

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Section: Triple Solid-liquid-solid Layersupporting

confidence: 88%

Experimental Evidence of the Existence of Bound States in the Continuum and Fano Resonances in Solid-Liquid Layered Media

Amrani¹,

Quotane²,

Ghouila-Houri

et al. 2021

Phys. Rev. Applied

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“…These results show that one can achieve a good filtering in one output keeping the other output unaffected by appropriately choosing the lengths of the different segments and stubs along the two outputs. In order to give an experimental validation of the above theoretical results, we performed an experiment using standard coaxial cables in the radio frequency domain [52]. The experiment is carried out using coaxial cables and a vector network analyzer.…”

Section: Numerical and Experimental Resultsmentioning

confidence: 97%

Y-Shaped Demultiplexer Photonic Circuits Based on Detuned Stubs: Application to Radiofrequency Domain

Mouadili

Khattou²,

Amrani³

et al. 2021

Photonics

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We present a theoretical and experimental study of photonic demultiplexers based on detuned stubs. The demultiplexers consist of Y-shaped structures with one input line and two output lines. Two different types of structures are proposed to achieve a selective transfer of a single mode in one output line without disturbing the second one. (i) In the first platform each output contains two different stubs attached at two different sites (U-shaped resonators). We derive in closed form the geometrical parameters of the stubs to achieve a selected frequency in each line while keeping the other line unaffected. The frequency selection can be made on the basis of two different mechanisms, namely a Fano or an electromagnetic induced transparency (EIT) resonance. Consequently, different demultiplexing schemes can be designed by a combination of the two mechanisms, such as Fano-Fano, Fano-EIT or EIT-EIT. In particular, the width of the Fano or EIT resonances can become zero for an appropriate choice of the stubs’ lengths, giving rise to trapped modes also called bound in continuum states (BICs) with infinite quality factors. We also show that the crosstalk between the two outputs can reach minimum values around −45 dB. (ii) In the second platform, each output line contains a photonic comb with a defect stub. The latter is appropriately designed to filter one or a few frequencies in the bandgap of the photonic comb. The analytical calculations are performed with the help of the Green’s function method which enables us to derive the transmission and reflection coefficients as well as the density of states (DOS). These results are confirmed by experimental measurements using coaxial cables in the radio frequency domain.

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“…This fitting procedure enables to deduce a useful expression for ε versus the frequency, namely ε = ( f f 0 ) −0.5 where the frequency f is expressed in Hz and f 0 = 9200 Hz. Further details and a photograph of the experimental setup can be found elsewhere [77,78].…”

Section: Methodsmentioning

confidence: 99%

Scaling Law, Confined and Surface Modes in Photonic Fibonacci Stub Structures: Theory and Experiment

et al. 2020

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We investigate both theoretically and experimentally the properties of electromagnetic waves propagation and localization in periodic and quasi-periodic stub structures of Fibonacci type. Each block constituting the Fibonacci sequence (FS) is composed of an horizontal segment and a vertical stub. The origin of the primary and secondary gaps shown in such systems is discussed. The behaviors and scattering properties of the electromagnetic modes are studied in two geometries, when the FS is inserted horizontally between two semi-infinite waveguides or grafted vertically along a guide. Typical properties of the Fibonacci systems such as the fragmentation of the frequency spectrum, the self-similarity following a scaling law are analyzed and discussed. It is found that certain modes inside these two geometries decrease according to a power law rather than an exponential law and the localization of these modes displays the property of self-similarity around the central gap frequency of the periodic structure where the quasi-periodicity is most effective. Also, the eigenmodes of the FS of different generation order are studied depending on the boundary conditions imposed on its extremities. It is shown that both geometries provide complementary information on the localization of the different modes inside the FS. In particular, in addition to bulk modes, some localized modes induced by both extremities of the system exhibit different behaviors depending on which surface they are localized. The theory is carried out using the Green’s function approach through an analysis of the dispersion relation, transmission coefficient and electric field distribution through such finite structures. The theoretical findings are in good agreement with the experimental results performed by measuring in the radio-frequency range the transmission along a waveguide in which the FS is inserted horizontally or grafted vertically.

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Comparison of density of states and scattering parameters in coaxial photonic crystals: Theory and experiment

Cited by 18 publications

References 70 publications

Experimental Evidence of the Existence of Bound States in the Continuum and Fano Resonances in Solid-Liquid Layered Media

Experimental Evidence of the Existence of Bound States in the Continuum and Fano Resonances in Solid-Liquid Layered Media

Y-Shaped Demultiplexer Photonic Circuits Based on Detuned Stubs: Application to Radiofrequency Domain

Scaling Law, Confined and Surface Modes in Photonic Fibonacci Stub Structures: Theory and Experiment

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