Multilayer Resonator Research Articles

Echo-free quality factor of a multilayer axion haloscope

We report a methodology to determine the quality factor (Q) of wavy dark matter detectors equipped with multilayered resonators, including Fabry-Pérot interferometers and the so-called dielectric haloscope. An anechoic chamber enables the observation of the resonance frequency and its amplitude for an unlimited series of layers for the first time, which is conveniently filtered. The frequency-normalized power enhancement measured in a Dark Photons and Axionlike Particles Interferometer (DALI) prototype is a few hundred per layer over a sweep bandwidth of a few dozen of megahertz. In light of this result, this scaled-down prototype is sensitive to axions saturating the local dark matter density with a coupling to photons between gaγγ≳10−12 and gaγγ≳few×10−14 GeV−1 at frequencies of several dozens of gigahertz once cooled down to the different working temperatures of the experiment and immersed in magnetic fields ranging from about 1 to 10 T; while the sensitivity of the full-scale DALI is projected at gaγγ≳few×10−15 GeV−1 over the entire 25–250 μeV range since Q≳104 is expected. Published by the American Physical Society 2024

Enhancing railway noise reduction through advanced multilayer acoustic absorbent systems with tunable resonators

Railway noise poses a significant environmental challenge, prompting the need for effective mitigation strategies. In response, noise barriers are often employed to reduce noise near railways. This research focuses on the use of porous materials, more specifically porous concrete, for acoustic absorption, particularly in the context of railway noise reduction. A novel approach is proposed, wherein porous multilayer metamaterial systems are developed, with each layer's macroscopic parameters strategically optimized to enhance the overall sound absorption curve. Additionally, to broaden the frequency range of noise attenuation, tunable resonators are seamlessly integrated into the multilayer system. The analytical framework for analyzing both the multilayer system and resonators involves employing equivalent fluid models and the analytical transfer matrix method. Linear regressions were employed to establish relationships between porosity, density, and other macroscopic parameters, enabling the derivation of the sound absorption curve solely from these parameters. Through systematic optimization and integration of resonators, it is expected that, the proposed approach demonstrates significant advancements in railway noise reduction efficacy across a wide frequency range. This research aims to contribute to the development of more efficient and versatile acoustic absorbent systems for mitigating railway noise pollution.

Unprecedented mechanical wave energy absorption observed in multifunctional bioinspired architected metamaterials

In practical engineering, noise and impact hazards are pervasive, indicating the pressing demand for materials that can absorb both sound and stress wave energy simultaneously. However, the rational design of such multifunctional materials remains a challenge. Herein, inspired by cuttlebone, we present bioinspired architected metamaterials with unprecedented sound-absorbing and mechanical properties engineered via a weakly-coupled design. The acoustic elements feature heterogeneous multilayered resonators, whereas the mechanical responses are based on asymmetric cambered cell walls. These metamaterials experimentally demonstrated an average absorption coefficient of 0.80 from 1.0 to 6.0 kHz, with 77% of the data points exceeding the desired 0.75 threshold, all with a compact 21 mm thickness. An absorptance-thickness map is devised for assessing the sound-absorption efficiency. The high-fidelity microstructure-based model reveals the air friction damping mechanism, with broadband behavior attributed to multimodal hybrid resonance. Empowered by the cambered design of cell walls, metamaterials shift catastrophic failure toward a progressive deformation mode characterized by stable stress plateaus and ultrahigh specific energy absorption of 50.7 J/g—a 558.4% increase over the straight-wall design. After the deformation mechanisms are elucidated, a comprehensive research framework for burgeoning acousto-mechanical metamaterials is proposed. Overall, our study broadens the horizon for multifunctional material design.

Design of Acetaldehyde Gas Sensor Based on Piezoelectric Multilayer Microelectromechanical System Resonator.

Acetaldehyde is a volatile organic compound that can cause damage at the cellular and genomic levels. The monitoring of acetaldehyde gas at low concentrations requires fast-response and low-cost sensors. Herein, we propose the design of an acetaldehyde gas sensor based on a low-cost Microelectromechanical System (MEMS) process. This sensor is formed by a single-clamped piezoelectric multilayer resonator (3000 × 1000 × 52.2 µm) with a simple operating principle and easy signal processing. This resonator uses a zinc oxide piezoelectric layer (1 µm thick) and a sensing film of titanium oxide (1 µm thick). In addition, the resonator uses a support layer of 304 stainless steel (50 µm thick) and two aluminum layers (100 nm thick). Analytical and Finite-Element Method (FEM) models are developed to predict the mechanical behavior of the gas sensor, considering the influence of the different layers of the resonator. The analytical results agree well with respect to the FEM model results. The gas sensor has a first bending frequency of 4722.4 Hz and a sensitivity of 8.22 kHz/g. A minimum detectable concentration of acetaldehyde of 102 ppm can be detected with the proposed sensor. This gas sensor has a linear behavior to detect different acetaldehyde concentrations using the frequency shifts of its multilayer resonator. The gas sensor design offers advantages such as small size, a light weight, and cost-efficient fabrication.

Resonant Frequencies of TE0mn modes in multilayered resonators containing uniaxial anisotropic dielectrics with complex shapes

Resonant Frequencies of TE0mn modes in multilayered resonators containing uniaxial anisotropic dielectrics with complex shapes

3D Bulk Metamaterials with Engineered Optical Dispersion at Terahertz Frequencies Utilizing Amorphous Multilayered Split-Ring Resonators.

A 3D bulk metamaterial (MM) containing amorphous multilayered split-ring resonators is proposed, fabricated, and evaluated. Experimentally, the effective refractive index is engineered via the 3D bulk MM, with a contrast of 0.118 across the frequency span from 0.315 to 0.366 THz and the index changing at a slope of 2.314 per THz within this frequency range. Additionally, the 3D bulk MM exhibits optical isotropy with respect to polarization. Moreover, the peak transmission and optical dispersion are tailored by adjusting the density of the split-ring resonators. Compared to reported conventional approaches for constructing bulk MMs, this approach offers advantages in terms of the potential for large-scale manufacturing, the ability to adopt any shape, optical isotropy, and rapid optical dispersion. These features hold promise for dispersive optical devices operating at THz frequencies, such as high-dispersive prisms for high-resolution spectroscopy.

Control of the coupling degree between surface plasmon and microcavity mode in dual-cavity OLEDs

The metal/dielectric/metal (MDM) multilayer resonator is of increasing interest because of its functionality of surface plasmons generated at the interfaces. We aimed to control the EL spectra of OLED with an MDM electrode by actively utilizing the plasmon-microcavity coupling. The change in EL spectra of OLED with MDM electrode was simulated depending on the design of MDM structures by FDTD simulations. The strength of the plasmon-microcavity coupling can be controlled by the thickness of the Ag film in AZA, which can determine the tuning range of the EL peak position.

Modeling and characterization of deeply etched multilayer resonators under partial coherent excitation via multimode optical fibers

Recently, there has been a resurgence of interest in multimode optical fibers illuminated by a white light source. Largely, in anticipation of many integrated applications in the biomedical domain and spectral sensing benefiting from the broad spectral range and high numerical aperture (NA). Along these lines, the output light from these fibers can be captured by the physics of partially coherent sources. While the Gaussian Schell model has provided a framework for studying partial coherence, to our knowledge, its impact on microstructures remains unexplored. As the sheer complexity arising from the interplay between partial coherence and microstructures transfer function has posed fundamental challenges in deciphering their response. In this work, we introduce a comprehensive numerical model paired with experimental validation to assess the performance of multilayer optical resonators, which are meticulously crafted through high aspect ratio silicon etching under the influence of a partially coherent optical source. The model studies the effects of optical fiber NA, Bragg mirror order, cavity length, and surface roughness of the microstructures on the output of the resonator. The results show that the response under standard multimode fiber (MMF, partial coherent source) has lower insertion loss, more asymmetry versus wavelength, and larger full width at half maximum than the standard single mode fiber (full coherent source). A silicon-on-insulator chip is fabricated using 130 µm deep etching of silicon for Bragg mirrors with 2.25, 3, and 3.25 µm silicon layer widths and a different number of layers. The structures are characterized using a MMF of 62.5 µm core diameter illuminated by an infrared white light source. The theoretical results have been compared with the experimental results and a good agreement has been obtained.

Resonant Frequencies of TE0mn modes in multilayered dielectric-ferrite resonators with complex shapes

The method of evaluating the resonant frequencies of multilayered resonator containing demagnetized ferrites is presented. The detailed solution of Maxwell's equations for such a structure by means of the radial modes matching method for TE0mn modes is given. The results of calculations using developed and launched computer program are given. Results of calculations are compared with those obtained by other method using CST simulator. These results are in close agreement, which proves the correctness of the method. The developed solution, and the software program can be used to measure the initial permeability of ferrites.

A Multilayered GaAs IPD Resonator with Five Airbridges for Sensor System Application.

This work proposes a microwave resonator built from gallium arsenide using integrated passive device (IPD) technology. It consists of a three-layered interlaced spiral structure with airbridges and inner interdigital structures. For integrated systems, IPD technology demonstrated outstanding performance, robustness, and a tiny size at a low cost. The airbridges were made more compact, with overall dimensions of 1590 × 800 µm2 (0.038 × 0.019 λg2). The designed microwave resonator operated at 1.99 GHz with a return loss of 39 dB, an insertion loss of 0.07 dB, and a quality factor of 1.15. Additionally, an experiment was conducted on the properties of the airbridge and how they affected resistance, inductance, and S-parameters in the construction of the resonator. To investigate the impact of airbridges on the structure, E- and H-field distributions of the resonator were simulated. Furthermore, its use in sensing applications was explored. Various concentrations of glucose solutions were used in the experiment. The proposed device featured a minimum detectable concentration of 0.2 mg/mL; high sensitivity, namely, 14.58 MHz/mg·mL-1, with a linear response; and a short response time. Thus, this work proposes a structure that exhibits potential in integrated systems and real-time sensing systems with high sensitivity.

Application of an overlay for spurious suppression of multi-layered surface acoustic wave resonators with double busbar configuration

Abstract This paper discusses the suppression of a spurious resonance called the gap mode which appears when the double busbar configuration is applied to multi-layered surface acoustic wave resonators. Two kinds of overlay structures are proposed for the gap mode mitigation. First, the use of lossy ones is studied. The results indicate that the lossy overlay can effectively mitigate the gap mode response when the viscosity is adequate. The layer thickness has a negligible impact on the mitigation. Then, the discussion is extended to the application of high-acoustic-velocity materials as the overlay. The resonance frequency of the gap mode can be moved to the upper-frequency side without affecting the main resonance by simply depositing a high-velocity overlay to the gap region. Finally, the comparison and choice of overlay materials are also studied. The results point out that Si3N4 is the optimum choice for industrial use.

Multi-layer SPR biosensor for in-Situ Amplified monitoring of the SARS-CoV-2 omicron (B.1.1.529) variant

This article represents an analysis of the performance of multi-layer surface plasmon resonance (SPR) biosensors in detecting the transferable human SARS-CoV-2 Omicron (B.1.1.529) variant. The proposed multi-layer SPR biosensor performance is enhanced by integrating fine-tuning prisms, plasmonic metals, and two-dimensional (2D) transition metal dichalcogenides (TMDs) materials. To evaluate the performance of the multi-layer SPR sensor, the transfer matrix method (TMM) is employed. In numerical result, the proposed (CaF2/Cu/BP/Graphene) structure demonstrates the most favorable sensitivity and detection accuracy, characterized by a 410° angle shift sensitivity/refractive index unit (RIU). Additionally, the sensor achieves a detection accuracy (DA) of 0.4713, a quality factor (QF) of 94.25 RIU−1, a figure of merit (FOM) of 91.87, and a combined sensitivity factor (CSF) of 90.36. The presented sensor is also capable of detecting target biomolecule binding interactions between ligands and analytes at a range of concentrations (from 0 nM to 1000 nM), implying its potential use for detecting the omicron virus strain. The outcomes highlight the effectiveness of the presented sensor for real time, and label free detection, particularly in identifying the Omicron viral strain. Eventually, this research promises advanced biosensor technology, crucial for rapid viral variant detection and diagnostics.

Featuring heterogeneous composite of W-type hexagonal ferrite with 2D vanadium carbide MXene for wideband microwave absorption

In this study, W-type hexagonal ferrite BaCo1.2Zn0.8Fe16O27 (BCZF) was synthesized via solid-state sintering and V2CTx-MXene was chemically etched from its V2AlC MAX phase. Subsequently, BCZF and V2CTx composites were synthesized by hydrothermal integration of V2CTx on the surface of BCZF bonded by electrostatic forces at varying mass ratios. The extensive heterostructure interfacial morphology of two dimensional V2CTx and BCZF plays an explicit role in tuning the dielectric and magnetic loss characteristics of the synthesized composites. The dielectric-magnetic synergistic loss mechanism caused by interfacial polarization, strong multi-reflections, scattering between MXene multilayer structures, conduction loss, and magnetic resonance effectively optimized impedance matching to improve the attenuation ability of the synthesized composites. Remarkably, the BCZF@10%V2CTx composite achieved strong electromagnetic wave absorption ability with an effective absorption bandwidth (RL < −10 dB) of 8.0 GHz (10–18 GHz) which is superior to that of contemporary magnetic–dielectric hybrid composites. These results present a novel perspective on magnetic V2CTx-MXene composites for microwave absorption applications, and provide a basis for the design and development of high-performance cloaking materials.

Highly sensitive Ag/BaTiO3/MoS2 nano composite layer based SPR sensor for detection of blood and cervical cancer

In this article, a nano-composite Ag/BaTiO3/MoS2 multilayer coating-based surface plasmon resonance (SPR) sensor with high sensitivity and figure of merit for the detection of cancer cells is analyzed. The proposed SPR biomedical sensor structure is built on the angular interrogation approach to utilizing the refractive index component, attenuated total reflection (ATR) analysis is employed to identify different kinds of cancer cells. The resonance angle varied as the refractive index (RI) of healthy and cancerous cells changed. Which ranged from 1.368 to 1.392 for increasing concentration in cervical (HeLa cells) and blood (Jurkat cells), RI 1.376 to 1.390 changes as the concentration of cancerous cells increases in healthy cells. The maximum estimated sensitivities for cervical (HeLa) and blood (Jurkat) cancer cells based on numerical data were 271.25 deg/RIU and 290.714 deg/RIU, respectively. The proposed BK7/Ag/BaTiO3/ MoS2has the ability to identify cancerous and healthy cells with the greatest overall sensitivity, as demonstrated by layered structures. Finally, the numerical results analyzed in this manuscript revealed a high degree of sensitivity and FoM compared to those of previous research studies.

Invited] Optimally configured multi-layer optical fiber plasmonic resonance sensor based on the orthogonal design method

A generic tool for the optimal design of multi-layer sensing structure of the optical fiber plasmonic resonance based on the orthogonal design method is proposed and demonstrated. The orthogonal design method is conducted to determine the optimal type and thickness of coating materials using a finite number of solutions. A novel three-layer sensing structure with enhanced spectral characteristic of resonance is developed to evaluate the feasibility of the orthogonal design method. The sensitivity and the figure of merit of the resonance optimized for the type and the thickness of coating materials achieve up to 3560 nm/RIU and 62.129 RIU−1, respectively. Such sensitivity is 97.7 % higher than that of the sensor with 40-nm single Au layer. Meanwhile, the efficiency of the analysis combination is increased by up to mk-2-1×100%. Our work is focused on the multi-structure parameter design of optical fiber plasmonic resonance sensors and can achieve the optimized configuration of the sensing performance. It has demonstrated the promising prospects in the flexible design of the plasmonic resonance curve and in the high-sensitivity and multi-parameter detection of the plasmonic resonance.

Investigation of a Large-Mode-Area Fiber Designed for 2.0 μm Based on Multi-Layer Holes Resonance

Investigation of a Large-Mode-Area Fiber Designed for 2.0 μm Based on Multi-Layer Holes Resonance

Design of heterostructure one-port SAW resonator with improved bandwidth using Si and LiNbO3 layer

In this research work, we have designed a heterostructure one-port surface acoustic wave (SAW) resonator. The multi-layer one port SAW resonator is made of a silicon (Si) substrate as base material, 128 ͦ rotated Y-cut X- propagated lithium niobate (LiNbO3) as piezoelectric substrate, and Inter Digital Transducers (IDTs) made of aluminium. This model is designed to operate on a wide frequency of 4–5 GHz with a resonance frequency of 4.74 GHz. Various parameters are taken into consideration during the study and analysis such as high-quality factor, wider bandwidth, better electromechanical coupling coefficient, and a true Figure of merit (FoM). The obtained Quality factor and the electromechanical coupling coefficient (k2) of the designed model are 2700 and 0.18. By using the wide range of frequencies, the bandwidth for the designed model is 1.74 MHz. The obtained results show that the device’s performance of the one port multilayer SAW resonator using the Al/128°YXLiNbO3/Si multi-layered substrate exhibits a commercial application in the 5 G wireless communication system.

Enhanced electrical transport properties of Cr-substituted Mg2–Y-type hexaferrites for power applications

The impact of Cr3+ substitution on the electrical and dielectric properties of Y-type hexaferrites with composition Ba2Mg2CrxFe12-xO22 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) was synthesized by the sol-gel auto combustion technique. The lattice parameters 'a' and 'c' slightly increase with the substitution content of Cr3+, and some other physical parameters, including porosity, microstrain, dislocation density, specific surface area, and stacking fault coefficient, were determined from XRD data. FTIR spectra confirm the formation of iron oxide base material by the appearance of three signature bands at precisely 429, 474, and 499 cm-1 due to Fe–O vibrations at octahedral and tetrahedral sites. Substituting Cr3+ at the octahedral site enhanced the room temperature DC electrical resistivity from 6.89 × 109 to 2.27 × 1010 Ω-cm. Temperature-dependent DC electrical resistivity exhibits semiconducting behavior. There is a direct relation between resistivity and activation energy. The dielectric behavior of Cr3+ substituted samples in the frequency range of 1 MHz–6 GHz was understood based on the conduction mechanism through the hopping of electrons between Fe3+ and Fe2+ ions and the Maxwell-Wagner Model. In impedance spectroscopy studied using Cole-Cole plots, most dielectric response arises from the contribution of the grain boundary effect. With the substitution of Cr3+, dielectric losses decreased. A very high Q-value around 1 GHz was observed, suggesting that these hexaferrites are efficient materials for many high-frequency applications, such as multi-layer chip inductors (MLCI), dielectric resonators, and power applications.

Advancing Raman spectroscopy of erythrocytes with 3D-printed acoustofluidic devices

Acoustofluidics is a technique that utilizes the forces produced by ultrasonic waves and fluid flows to manipulate cells or nano-/microparticles within microfluidic systems. In this study, we demonstrate the feasibility of performing the Raman analysis of living human erythrocytes (Erys) within a 3D-printed acoustofluidic device designed as a half-wavelength multilayer resonator. Experiments show that a stable and orderly Ery aggregate can be formed in the pressure nodal plane at the resonator's mid-height. This has a significant potential for improving the applicability of Raman spectroscopy in single Ery analysis, as evidenced by the acquisition of the spectrum of healthy and pre-heated Erys without substrate interference. Moreover, principal component analysis applied on the obtained spectra confirms the correct Ery group identification. Our study demonstrates that 3D-printed acoustofluidic devices can improve the accuracy and sensitivity of Raman spectroscopy in blood investigations, with potential clinical applications for noninvasive disease diagnosis and treatment monitoring.

Material dissipation of graphene resonators

Graphene resonators hold a promising potential to be integrated into nanoscale sensors and electronic devices. Therefore, understanding the physics underlying their dissipation mechanisms is essential. Here we investigate the dissipation of graphene through a study of graphene foam (GF) resonators. We show that intrinsic material dissipation, related to interlayer friction, is a primary source of energy dissipation in graphene. We fabricated GFs with varying wall thicknesses and characterized their frequency responses under ambient and vacuum conditions. Additionally, we investigated their atomic structure by using Raman analysis, high-resolution scanning electron microscopy, and transmission electron microscopy. While air losses are considered the primary dissipation source of micro- and nano-electromechanical systems (M/NEMS) operating under ambient conditions, we show that friction between graphene layers is a comparable source for energy dissipation and, thus, it limits the dynamic amplification of multilayer graphene resonators even when they are operated under high-vacuum conditions. We show that the friction between the layers is enhanced when multiple layers exist and that dissipation is further amplified by microscopic defects, such as cracks and grain boundaries, or by the existence of amorphous carbon. Thus, we uncover the fundamental physical behavior of graphene.