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The emission properties of a single Si microdisk resonator with a deterministically embedded GeSi quantum dot (QD) stack have been investigated. The results demonstrate selective excitation of different modes of the resonator depending on the position of QDs. The photoluminescence (PL) spectrum changes dramatically depending on the location of the QDs in the resonator. For the central QD position, the excitation of low Q-factor Mie modes with high field concentration in the center of resonator results in the appearance of a broad PL band. When the stack of QDs is shifted from the center to the edge of the Si resonator, the quenching of this PL band is observed and narrow PL peaks corresponding to whispering gallery modes (WGMs) appear in the PL spectrum. It is found that resonator modes can be excited not only by QDs but also by the radiation of the wetting layer. It is shown that a GeSi island on the top of the QD stack, not covered by silicon, can play the role of a nanoantenna, redirecting radiation to the upper half-space, which is especially important for WGMs that usually radiate sideways. [ABSTRACT FROM AUTHOR]

We present a novel approach for actively controlling electromagnetically induced transparency (EIT) analogs in a single-mode microstrip cavity. This cavity is side-coupled with a pair of varactor-loaded split-ring resonators (SRRs). The EIT-like effect is achieved through resonance hybridization between the paired SRRs with frequency detuning. The microstrip cavity is utilized to enhance the EIT-like transmission properties, including Q-factor and group delay. Varactor diodes, soldered at the gap of the SRRs, are biased electrically through a DC voltage source. This dynamic modulation setup allows for the tuning of the enhanced EIT analog. Experimental results demonstrate that the enhanced EIT-like transmission spectrum can be tuned reversibly by 378 MHz with respect to the transmission dip frequency of 2.464 GHz under the bias voltage ranging from 0 to 5 V. Simultaneously, the controlled transmission spectrum enables a remarkable change in group delay of 10.9 ns. Moreover, the modulation amplitude of the composite SRRs-cavity structure reaches a peak value of up to 34.5 dB, significantly higher than the 6.4 dB of the individual SRRs pair. These results hold promise for inspiring innovation in actively controlled photonic devices for practical applications. [ABSTRACT FROM AUTHOR]

A plasma refractive index sensor based on metal–insulator–metal waveguide-coupled analogy T-shaped with double-ring resonators was designed. The transmission characteristics of the waveguide were investigated using the finite-difference time-domain method with perfectly matched layer absorbing boundary conditions. By optimizing the structure parameters, the sensor obtained the maximum sensitivity (S) of 1110 nm/RIU and the maximum figure of merit of 1904. The results demonstrate that this new structure can generate dual Fano resonances and exhibit typical refractive index sensing functionality, which provides valuable insights into the design and optimization of plasma refractive index sensors. Additionally, by measuring the concentration of plasma solution and glucose solution, it has been proven that the structure has the prospect of practical application. [ABSTRACT FROM AUTHOR]

The lithographically tunable and small size features of Lamb wave resonators (LWRs) take a bright future for their use in high frequency narrow band filters. Resonant frequency drift due to temperature variation has a large impact on the narrower passband and a temperature coefficient of frequency (TCF) closer to 0 can broaden the stable temperature range of the resonator. This paper proposes a method of etching grooves in the area of the piezoelectric layer not covered by the Interdigital transducer (IDT) electrodes to improve the temperature stability of the Lamb resonator. Through the finite element method and theoretical analysis, the phase velocity, group velocity, and TCF dispersion curve of different modes of the resonator with groove structure were determined. The reason for the change of TCF under different normalized thicknesses of AlN was explained through the conversion of the LWR from a contour mode resonator (CMR) to a Cross-Sectional Lamé Mode Resonator. Simulation and test have shown that etching grooves have the effect of reducing TCF by adjusting the electromechanical coupling coefficient. The test shows that 205 nm-depth grooves can lower the TCF of the S0 mode IDT-Open LWR from −13.3 to −5.1 ppm/°C and S1 mode from −36.8 to −9.0 ppm/°C, respectively. The TCF of S0 and S1 mode LWRs decreased by 61.7% and 75.5%, respectively, after 205 nm groove etching. The groove etching method greatly raises the temperature stability of the LWR, enabling Lamb wave filters to operate stably over a wider temperature range. [ABSTRACT FROM AUTHOR]

Resonators based on two-dimensional (2D) materials have exceptional properties for application as nanomechanical sensors, which allows them to operate at high frequencies with high sensitivity. However, their performance as nanomechanical sensors is currently limited by their low quality (Q)-factor. Here, we make use of micro-electromechanical systems (MEMS) to apply pure in-plane mechanical strain, enhancing both their resonance frequency and Q-factor. In contrast to earlier work, the 2D material resonators are fabricated on the MEMS actuators without any wet processing steps using a dry-transfer method. A platinum clamp, which is deposited by electron beam-induced deposition, is shown to be effective in fixing the 2D membrane to the MEMS and preventing slippage. By in-plane straining the membranes in a purely mechanical fashion, we increase the tensile energy, thereby diluting dissipation. This way, we show how dissipation dilution can increase the Q -factor of 2D material resonators by 91%. The presented MEMS actuated dissipation dilution method does not only pave the way toward higher Q -factors in resonators based on 2D materials, but also provides a route toward studies of the intrinsic loss mechanisms of 2D materials in the monolayer limit. [ABSTRACT FROM AUTHOR]

The absorption of a free-standing ultra-thin film supporting a single resonant mode is, in principle, limited to 50%. Based on the degenerate critical coupling (DCC) of dipole modes, silicon Mie resonators can overcome the absorption limit and achieve perfect absorption in the green light range. DCC requires that the radiative loss of each dipole mode matches material loss. Due to the material properties of silicon, the material loss varies with wavelength. Therefore, flexible tuning of radiative loss to match the wavelength-dependent material loss is crucial for realizing DCC-based perfect absorbers. In this study, we propose that a 45-degree rotation of cubic Mie resonators enhances the radiative loss of electric dipole mode. Hence, the DCC-based perfect absorption can be extended to the violet light range. In addition to applications in photodetectors and imaging sensor pixels, the proposed perfect absorber has great potential to become nonlinear elements based on the photothermal effect for photonic neuromorphic computing due to its temperature-dependent scattering. [ABSTRACT FROM AUTHOR]

We present experimental demonstration and modeling of mechanical wave propagation in a quasi-one-dimensional (quasi-1D) phononic crystal (PnC) waveguide (WG) constructed from a periodic array of single-crystal cubic-silicon carbide (3C-SiC) coupled micromechanical resonators, with an exceptional dynamic range exceeding 92 dB. The PnC design comprises 50 periodic cells, enabling the propagation of flexural mechanical waves in high-frequency and very-high-frequency bands, featuring a broad PnC bandgap spanning approximately 24–27.5 MHz. Furthermore, the 3C-SiC PnC WG exhibits excellent characteristics, including a high group velocity of 350 m/s and a low transmission loss of 0.69 dB/mm, enabling efficient guidance and support for mechanical waves across extended distances before reaching the noise level of the device. These attributes of the PnC WG, as demonstrated in this study, may open possibilities for the development of device platforms with applications in on-chip signal processing, sensing, and quantum transducer technologies. [ABSTRACT FROM AUTHOR]

Within the field of elastic metamaterials, topological metamaterials have recently received much attention due to their ability to host topologically robust edge states. Introducing local resonators to these metamaterials also opens the door for many applications such as energy harvesting and reconfigurable metamaterials. However, the interactions between phenomena from local resonance and modulation patterning are currently unknown. This work fills that gap by studying multiple cases of spatially modulated metamaterials with local resonators to reveal the mechanisms behind bandgap formation. Their dispersion relations are determined analytically for infinite chains and validated numerically using eigenvalue analysis. The inverse method is used to determine the imaginary wavenumber components from which each bandgap is characterized by its formation mechanism. The topological nature of the bandgaps is also explored through calculating the Chern number and integrated density of states. The band structures are obtained for various sources of modulation as well as multiple resonator parameters to illustrate how both local resonance and modulation patterning interact together to influence the band structure. Other unique features of these metamaterials are further demonstrated through the mode shapes obtained using the eigenvectors. The results reveal a complex band structure that is highly tunable, and the observations given here can be used to guide designers in choosing resonator parameters and patterning to fit a variety of applications. [ABSTRACT FROM AUTHOR]

The hemispherical shell resonator (HSR) is the core element of the hemispherical resonator gyroscope (HRG), and its frequency mismatch is a key property influencing gyroscope accuracy. Investigating the mechanism of frequency mismatch is vital for improving the quality of HSRs and performance of HRGs. Midsurface radius imperfections and thickness imperfections are two principal causes of frequency mismatch, but their combined effects have rarely been discussed. This paper develops a model to comprehensively analyze the frequency mismatch of HSRs with both radius and thickness imperfections. The model derives a quantitative relation between the frequency mismatch and the two imperfections, and provides principles for evaluating dominant imperfections. To validate the model, we conduct experiments on a batch of 12 HSRs with random geometric imperfections. We apply the model in calculating the theoretical frequency mismatches of these HSRs, and the results agree well with the experimental data. The experiment also confirms that for macro-HSRs, thickness imperfections have a larger impact than radius imperfections, and the frequency mismatch is approximately linear to the fourth thickness harmonic. Our research can be a useful reference for the design and fabrication of HSRs and may open new possibilities for high-precision manufacture of HRGs. [ABSTRACT FROM AUTHOR]

In a class of high quality (Q-) factor dielectric resonators with low radiative losses, including popular whispering-gallery mode (WGM) resonators with high azimuthal mode numbers, due to high confinement of modal field in dielectric, the Q-factor is limited by the value of inverse dielectric loss tangent of dielectric material. Metal enclosures necessary for device integration only marginally affect the Q-factor while eliminating the residual radiative loss and allowing the optimization of input and output coupling. While very high Q-factors ∼ 200 000 are available in sapphire WGM resonators in X-band, at millimeter wave frequencies increasing dielectric loss limits the Q-factor to much smaller values, e.g. ∼50000 and ∼25000 for quasi-TE and quasi-TM modes, correspondingly, at 36 GHz. The use of distributed Bragg reflection (DBR) principle allows to push modal energy outside dielectric while also isolating it from Joule losses in metallic enclosure walls. Very high Q ∼ 600 000 > --> t g δ has been demonstrated in X-band [C. A. Flory and R. C. Taber, IEEE Trans. Ultrason., Ferroelectr., Freq. Control 44, 486–495 (1997).] at the expense of impractically large dimensions. In this work, we report on the assembly and testing of a compact Ka-band sapphire distributed Bragg reflector cavity characterized with Q-factor seven times larger than one predicted by the material's dielectric loss at the frequency of interest. An intrinsic Q-factor of ∼ 200 000 is demonstrated at 36 GHz for the lowest order TM-mode of a sapphire DBR. The resonator has 50 cm 3 volume, smaller than previously demonstrated DBRs. [ABSTRACT FROM AUTHOR]

A novel mode-localized acceleration sensor employing an electrostatically coupled resonator and integrating a lever with proof mass is micromachined using standard silicon on insulator (SOI) technology. In order to determine the linear dynamic range of the sensor, a reduced order model is developed while assuming that the resonators vibrate below the critical amplitude. Then, open-loop and closed-loop testing platforms are established to measure the performance of the linearly operating accelerometer in a vacuum environment (less than 5 Pa). Moreover, the corresponding amplifier circuit based on the capacitive detection principle is designed in order to extract and amplify the current signal from the resonators. The obtained results show that the accelerometer sensitivity can be increased by three orders of magnitude when using the relative shift of amplitude ratio as the output metric instead of the relative shift of frequency, and the experimental measurements are consistent with the theoretical predictions. Remarkably, the Allan standard deviation of the mode-localized acceleration sensor obtained from the closed-loop testing circuit is around 5.03 μg. [ABSTRACT FROM AUTHOR]

Hybrid spin-mechanical systems offer a promising platform for advancing quantum science and technology. However, practical implementation of applications within these hybrid quantum systems demands the seamless integration of supplementary physical components. In this context, we present a proposal for a multi-mode spin-mechanical setup, featuring the utilization of three-mode coupling nanomechanical carbon nanotube (CNT) resonators. These resonators interact with each other via a phase-dependent phonon-exchange mechanism, which is coupled to the same nitrogen vacancy (NV) centers in diamond. Based on the modulation of the phonon–phonon coupling phase and leveraging the triple Fano-like resonance phenomenon, a tripling of electromagnetically induced transparency (EIT) becomes achievable within the system. This tripling is accompanied by swift dispersion, leading to a subtle advancement or delay in outcomes. The phenomenon of triple Fano-like resonance, alongside the resulting triple EIT, engenders noteworthy slow-to-fast and fast-to-slow light effects, which is theoretically demonstrated in CNT resonators, with both identical and distinct frequencies. The findings underscore that CNT resonators with varying frequencies can evoke a more pronounced transition in the slow–fast–slow and fast–slow–fast light effects. This study lays the foundation for the application of phonon-mediated optical information storage and processing. [ABSTRACT FROM AUTHOR]

We deduce equations to calculate coupling coefficients of diamond micro-ring resonators. The equations can be used universally at any wavelength but not limited to the transmission peaks/valleys, and can be adapted with triangular cross-sections and tapered waveguides. Consequently, we build three models in accordance to different diamond processing technologies. These models deal with ring resonators with either rectangular cross sections, or triangular cross sections, or with tapered bus for triangular cross sections. The calculated coupling coefficients can be well fitted by exponential decay functions of gap d. Due to geometrical limitations, triangular-cross-sectional diamond resonators are shown to have much smaller (factor 20) coupling coefficients than those of rectangular-cross-sectional resonators. A tapered bus is shown to be beneficial to increase the coupling coefficient. Besides the calculation of coupling coefficients, the method presented in the paper can also be used to calculate the bending loss of micro-ring resonators, as a complement to the existing methods. [ABSTRACT FROM AUTHOR]

The recently proposed concept of electric chiral magnonic resonator (ECMR) has been extended to include usage of spin–orbit torques (SOT). Unlike the original version of ECMR which was based on voltage controlled magnetic anisotropy (VCMA), the spin wave amplification power by this new version of ECMR (pumped by SOT) no longer depends on the phase of the incident wave, which is highly desirable from an application point of view. The performance of the SOT pumped ECMR has been compared with the case of amplification by applying SOT pumping directly to a waveguide (without any ECMR involved). It is argued that at the expense of narrowing the bandwidth (i.e., slower amplifier response), the advantage of the former configuration (amplification by a SOT pumped ECMR) over the latter (amplification by direct SOT pumping the waveguide) is to offer gain, while at the same time, maintaining system stability (avoidance of auto-oscillations). Non-linear behavior of the SOT pumped ECMR has been analyzed. It is demonstrated that by cascading a SOT ECMR operating in an off-resonance mode together with a VCMA biased passive ECMR, it is possible to produce a magnonic neuron with a transmitted signal magnitude larger than the input in the firing state. [ABSTRACT FROM AUTHOR]

Metasurface analogs of electromagnetically induced transparency (EIT) are attracting sustaining attention due to their ability to maintain transparency windows accompanied by extreme dispersion of propagating waves, which are important for slow light devices and highly sensitive optical sensors. In this paper, we study theoretically, numerically, and experimentally the conditions for the existence of multi-band transparency windows in the metasurface supported by the interaction of dipole modes in an asymmetric unit cell. The unit cell is composed of a single bright resonator and several dark resonators made in the form of rectangular metal patches. The manifestation of EIT is studied for different metasurface configurations by varying the number and positions of resonators used within the unit cell. To validate the slow-down effect caused by EIT, a prototype of the metasurface is fabricated and tested, providing a measurement of the group delay and bandwidth-delay product features. The obtained results clearly confirm the presence of four EIT-like transparency windows in the metasurface transmission spectra originating from the coupling between either quasi-TE or quasi-TM modes of the resonators. [ABSTRACT FROM AUTHOR]

We derive a coupled-mode theory (CMT) formulation for the fast analysis of periodic multi-element metasurfaces in the presence of radiation losses. Full-wave simulations of periodic multi-element metasurfaces are very time- and memory-consuming, especially as the size and complexity of the metasurface increase. The CMT formulation provides a considerably faster and efficient alternative. It results in a small system of equations with size equal to the number of supported resonator modes in the frequency range of interest, allowing to calculate the resonator mode amplitudes and, consequently, the metasurface response. Subsequently, we systematically derive analytical closed-form expressions for the coupling coefficients between two weakly coupled resonators in the presence of radiation losses and incorporate them into the CMT model, which is found important for the accurate description of the metasurface, while also providing insight into the underlying physics of complex metasurfaces. We validate the proposed formulation on benchmark examples of both metal- and dielectric-based metasurface absorbers (MSAs) by comparing the CMT results to spectral FEM simulations of the composing supercell. To further demonstrate the potential of the proposed formulation, as a proof of concept, we use the CMT to synthesize a larger optimized periodic multi-element MSA. A comprehensive comparison to full-wave FEM simulations of the composing supercell is included in terms of time and computational requirements, which shows that our method provides a valuable and efficient alternative solver for synthesizing complex metasurfaces. [ABSTRACT FROM AUTHOR]

All real systems are essentially non-conservative in nature, which is non-Hermitian in the fundamental premises of the quantum realm. Such open systems obeying parity-time (PT) symmetry can offer intriguing physics, which has sparked much attention in recent years. The thoughtful interplay of loss and gain in PT-symmetric systems can tune the eigenstates from real to complex space passing through a singular point known as an exceptional point (EP) with concurrently coalescing the discrete eigenstates. In this regard, artificially engineered near-field coupled metasurfaces provide a remarkable podium to introduce as well as control loss and coupling strength simultaneously, manifesting a practical channel to attain EP. Motivated by this notion, we have theoretically explored near-field coupled dark-bright-mode assisted terahertz metasurfaces imitating a typical non-Hermitian PT-symmetric system. Structurally, such metasurfaces are realized by utilizing a pair of orthogonally twisted near-field coupled split-ring resonators (bright-dark-resonators). We have meticulously examined such a system with two distinctive approaches, i.e., the loss parameter and inter-resonator coupling strength. Eventually, our exploration demonstrates that judicious modulation of the loss parameter can invoke an undemanding route to approach the other wisely elusive exceptional point. We believe that this comprehensive study of non-Hermitian quantum systems in a photonic context can lead to the development of accurate and precise ultra-sensitive sensors besides other futuristic photonic devices. [ABSTRACT FROM AUTHOR]

We study both numerically and experimentally an acoustic metasurface based on coupled Helmholtz resonators to obtain broadband low-frequency spectral responses for acoustic insulation. A hierarchical approach is proposed, starting from single and coupled Helmholtz resonators, up to a periodic array of resonators. To this end, we performed numerical simulations using the finite element method, in which the resonators are modeled as drilled rigid spheres in airborne environment and experimental demonstrations based on ping-pong balls as Helmholtz resonators in an acoustic reverberation box. We showed the alteration of the low-frequency response of acoustic insulation resulting from inter-unit coupling in acoustic metasurfaces, and the apparition of additional attenuation by inserting a plexiglass board as support for the structure. [ABSTRACT FROM AUTHOR]

In the paper, a metasurface is investigated, the unit cell of which consists of two resonators. We show that the breaking of the axial symmetry of the unit cell in such a structure leads to the appearance of two Fano resonances instead of one that is characteristic of the symmetric unit cell. The two resonances are different, one of which is symmetric and the other is asymmetric. This is confirmed by calculating the phases of currents in the adjacent resonators. Modeling results are confirmed by experimental investigation of the metasurface spectrum in a microwave frequency range showing two resonances measured experimentally. A detailed study of the currents flowing in the adjacent resonators of the unit cell demonstrates that currents at the Fano resonance dips flow either in phase or in antiphase with respect to the external electric field, whereas in peaks this difference is π /2. This confirms the interference nature of the Fano effect. [ABSTRACT FROM AUTHOR]

We report on InGaAs/GaAs quantum dot injection microdisk lasers laterally connected with a bus waveguide fabricated by planar technology from the same epi-structure. Various coupling schemes of microlaser with waveguide are studied including a microlaser attached to a waveguide (zero gap), a 100 nm gap for evanescence light outcoupling, and with a waveguide surrounding the resonator. The modes outcoupling and microlaser's loss (Q-factor) are analyzed by simulation of the lasers. A strong decrease in the number of the microdisk resonance lines associated with an increase in loss in the resonator due to the coupling with waveguide is observed in modeling and experimentally. We study the spectral and lasing parameters of the microdisk lasers, as well as characteristics of the outcoupled emission, and demonstrate efficient light outcoupling for 30 and 40 μm diameter continuous wave operating microdisk laser up to 96 °C. [ABSTRACT FROM AUTHOR]

Summary: A low profile, concave conformal ring cylindrical dielectric resonator antenna (CDRA) employing frequency selective surface (FSS) using split ring resonator (SRR) for wideband and high gain applications is presented. The ring CDRA loaded with the monopole is designed to excite the TM01δ mode to increase the antenna's bandwidth. The effect of a curved ground plane (GP) on the radiation performance of CDRA is studied. A 5 × 5 array of the SRR is placed above the conformal GP at a far‐field distance optimized to (2n ± 1) λ/4 from the radiating element to enhance the gain of the proposed structure. The planar CDRA with FSS is compared with the conformal CDRA with FSS and a 4.3 GHz improvement in bandwidth is observed due to the multiple reflection and surface reflection leading to a 3.2 dBi improvement in gain. An impedance bandwidth of 51.8% (5 to 8.5 GHz) with a maximum gain of 8.7 dBi at 7.3 GHz resonant frequency and 99% radiation efficiency at 5.9 GHz is offered by the proposed antenna with FSS. Additionally, the proposed CDRA has a low profile of 0.12 λ0 where λ0 is the lower cut‐off frequency's wavelength. A good agreement is observed between the simulated and measured results. [ABSTRACT FROM AUTHOR]

High‐index dielectrics or Super‐Mossian materials are essential for emerging nanophotonic applications. Several transition metal dichalcogenides (TMDCs) are promising as super‐Mossian dielectric materials. Molybdenum disulfide (MoS2) is an outstanding super‐Mossian TMDC exceeding Moss' rule prediction of its refractive index by nearly 40%. This high refractive index enables compact, multi‐functional, and high‐performance metadevices. Here, a MoS2 metasurface is experimentally demonstrated using resonators with volumes of nearly a tenth of those made of silicon. To harness their phase control ability, a MoS2 blazed metasurface is designed, fabricated, and demonstrated. The performance of the device is benchmarked by rigorous‐coupled‐wave‐analysis calculation. The results suggest that MoS2 holds great promise as a dielectric material platform for emerging nanophotonic technologies. [ABSTRACT FROM AUTHOR]

This research proposition introduces a novel microstrip antenna design that features triple notches for ultra-wideband (UWB) applications. The antenna, measuring 35.4 mm × 28.82 mm × 1.57 mm, incorporates rectangular and semi-circular slots, as well as a pentagonal stub. A modified U-shaped slot on the pentagonal stub creates one notched frequency band at 3.3–3.7 GHz. Additionally, two Split Ring Resonators (SRRs) are integrated into the antenna’s rear surface, resulting in two more notched bands at 5.1–5.8 GHz and 7.1–7.8 GHz. Operating within a frequency range from 3 to 11.2 GHz with VSWR ≤ 2, the antenna effectively excludes the triple stop bands at 3.3–3.7 GHz (11.4%), 5.1–5.8 GHz (12.8%) and 7.1–7.8 GHz (9.4%). The proposed antenna has been successfully prototyped and verified. An extensive result analysis has been conducted, confirming that the developed antenna is suitable for application in a range of wireless systems. Moreover, the article includes the implementation of an equivalent circuit for the proposed antenna. [ABSTRACT FROM AUTHOR]

ABSTRACT The rapid expansion of Internet of Things (IoT) applications presents unprecedented challenges for antenna design, demanding solutions that are versatile, efficient, and capable of operating across multiple frequency bands. This paper addresses these challenges through the development of a design of a multiband antenna using Auxiliary Classifier Wasserstein Generative Adversarial Network for IoT applications (DMA‐ACWGAN‐IoT). Here, the Auxiliary Classifier Wasserstein Generative Adversarial Network (ACWGAN) is employed to generate synthetic data representing electromagnetic field distributions and antenna characteristics across various frequencies. The proposed metamaterial‐based Multiple‐Input Multiple‐Output (MIMO) antenna contains four discrete elements, each provided by a micro strip feed. The structures overall width and length are 60 and 52 mm. The metamaterial is printed on a patch and dispersed from the fields with the most effective coupling. The proposed structures strong impedance bandwidth works at 8.3 GHz, 10.8 GHz, 12.3 GHz, 13.7 GHz, 16.1 GHz, and 18.1 GHz, fabricating the proposed antenna prototype using a substrate made of FR‐4 material. The proposed DMA‐ACWGAN‐IoT design provides 6.5 dB maximum gain and 25.40%, 21.60%, and 20.05% higher efficiency compared to existing dual band antenna design with resonance frequency prediction under machine learning models (DBA‐PRF‐ML), machine learning verification depending on a distinctive SWB multiple slotted four‐port high isolated MIMO antenna loaded with metasurface for the applications of IoT (SWB‐MIMO‐IOT‐ML), and dual‐band miniaturized composite right–left‐handed transmission line ZOR antenna along machine learning method for microwave communication (DB‐ZORA‐MC‐ML). [ABSTRACT FROM AUTHOR]

Benefitting from the mature, cost‐effective, and scalable manufacturing capabilities of complementary metal‐oxide‐semiconductor (CMOS) technology, silicon photonics has facilitated the seamless and monolithic integration of diverse functionalities, including optical sources, modulators, and photodetectors. Microresonators can generate multiple coherent optical frequency comb lines and serve as optical sources. However, at the telecom band, silicon suffers from two‐photon absorption and free‐carrier absorption, which severely hampers the realization of microcombs from a single silicon chip at telecom wavelengths until now. In this paper, a novel approach is presented and demonstrated with near‐infrared dual‐band frequency combs from a multimode silicon resonator. With a single pumping configuration, dual‐band combs are generated from the interaction between the pump and Raman Stokes fields by involving two different optical mode families but with similar group velocities. It is observed that the pump power required to generate dual‐band combs is as low as 0.7 mW. The work in bringing telecom microcombs to the silicon platform will advance silicon photonics for the next generation of monolithically integrated technology based on a single silicon chip, enabling new possibilities for further exploring silicon photonics‐based applications in optical telecommunications, sensing, and quantum metrology in the telecom band using a monolithic single silicon chip. [ABSTRACT FROM AUTHOR]

Generating coherent optical frequency combs in micro-ring resonators with Kerr nonlinearity has remarkably advanced the fundamental understanding and applications of temporal dissipative solitons. However, the spectrum of such soliton combs is restricted to the conventional definition of combs as phase-locked, equidistant lines in frequency. Here, we introduce a new class of floquet topological soliton combs that emerge in two-dimensional arrays of strongly coupled resonators engineered using floquet topology. Specifically, we demonstrate incommensurate combs where the comb lines are not equidistant but remain phase-locked. These incommensurate combs are generated by self-organized, phase-locked floquet topological soliton molecules that circulate the edge of the array. We show that these floquet topological solitons are robust and they navigate around defects, allowing for agile tunability of the comb line spacing. Our results introduce a new paradigm in using floquet engineering to generate unconventional frequency combs beyond those achievable with single or weakly coupled resonators. Optical frequency combs are conventionally defined as a set of phase-locked, equally spaced spectral lines. Here, using a two-dimensional array of Floquet topological ring resonators, the authors propose novel incommensurate combs with phase-locked spectral lines that are not all equally spaced. [ABSTRACT FROM AUTHOR]

In a nanomechanical resonator coupled to a quantum point contact, the back action of the electronic state on mechanical motion is studied. The quantum point contact conductance changing with subband index and the eigenfrequency of the resonator are found to correlate. A model is constructed explaining the frequency deviations by the variable ability of the quantum point contact to screen the piezoelectric charge induced by mechanical oscillations. The observed effects can be used to develop electromechanical methods for studying the density of states in quasi-one-dimensional systems. [ABSTRACT FROM AUTHOR]

A promising route towards the deterministic creation and annihilation of single-phonons is to couple a single-photon emitter to a mechanical resonator. The challenge lies in reaching the resolved-sideband regime with a large coupling rate and a high mechanical quality factor. We achieve this by coupling self-assembled InAs quantum dots to a small mode-volume phononic-crystal resonator with mechanical frequency Ωm/2π = 1.466 GHz and quality factor Qm = 2.1 × 103. Thanks to the high coupling rate of gep/2π = 2.9 MHz, and by exploiting a matching condition between the effective Rabi and mechanical frequencies, we observe the interaction between the two systems via correlations in the emitted photons. Our results represent a major step towards quantum control of the mechanical resonator via a single-photon emitter. Coupling a single-photon emitter to a mechanical resonator enables the generation of single phonons. Here, the authors study the interaction of a single-photon emitter and a phononic-crystal resonator in the sideband-resolved regime. [ABSTRACT FROM AUTHOR]

MEMS gyroscopes are well known for their outstanding advantages in Cost Size Weight and Power (CSWaP), which have inspired great research attention in recent years. A higher signal-to-noise ratio (SNR) for MEMS gyroscopes operating at larger vibrating amplitudes provides improved measuring resolution and ARW performance. However, the increment of amplitude causes strong nonlinear effects of MEMS gyroscopes due to their micron size, which has negative influences on the performance. This paper carries out detailed research on a general nonlinear mechanism on the sensors using parallel-plate capacitive transducers, which is called the gain nonlinearity in electrostatic actuation. The theoretical model established in this paper demonstrates the actuation gain nonlinearity causes the control-force coupling and brings extra angle-dependent bias with the 4th component for the whole-angle gyroscopes, which are verified by the experiments carried out on a micro-shell resonator gyroscope (MSRG). Furthermore, a real-time correction method is proposed to restore a linear response of the electrostatic actuation, which is realized by the gain modification with an online parameter estimation based on the harmonic-component relationship of capacitive detection. This real-time correction method could reduce the 4th component of the angle-dependent bias by over 95% from 0.003°/s to less than 0.0001°/s even under different temperatures. After the correction of actuation gain nonlinearity, the bias instability (BI) of whole-angle MSRG is improved by about 3.5 times from 0.101°/h to 0.029°/h and the scale factor nonlinearity (SFN) is reduced by almost one order of magnitude from 2.02 ppm to 0.21 ppm. [ABSTRACT FROM AUTHOR]

The mechanisms underlying the stability of the intensity imbalance between the left‐ and right‐circulating lasing modes in a GaN hexagonal microdisk resonator are investigated. Finite‐difference time‐domain simulations reveal that the imbalance is determined by the position of the point light source (seed light for lasing) inside the resonator. The coupling mechanism between the resonance modes and light from the source is clarified using numerical calculations. In addition, it is confirmed that light is highly coupled with one of the circulation modes when the source is placed off the bilateral symmetry axis of the mode near the side of the resonator, without any influence of the polarization of the source. The results indicate that the imbalance of the lasing modes observed in the experiments is determined by the position of the seed light near the side of the resonator, which must be spontaneous emission from impurities or defects, such as donor–acceptor pairs, donor‐bounded excitons, basal plane stacking faults, or the transition of free electrons in the conduction band to acceptor levels et al. [ABSTRACT FROM AUTHOR]

Corresponding to the different phase‐shifts of the interference modes, the whispering gallery mode resonator‐based Fano resonance exhibits a variety of unique spectral lineshapes that can be applied to sensing, optical signal processing, and so on. However, most approaches to lineshape tuning aim to alter the propagation phase‐shift or coupling strength, and generally suffer from relatively low efficiency and limited tuning range. In this paper, with a carefully designed waveguide‐taper coupled micro‐ring resonator structure and the assistance with the grating‐coupler, for the first time a near full‐lineshape selectivity of the Fano resonance is demonstrated in two isolated tuning dimensions of the frequency and transverse space, which means arbitrary lineshapes including the Lorentzian‐dip, asymmetric Fano peak or electromagnetically‐induced‐transparency (EIT)‐like peak can be obtained at a specific resonance wavelength in the whole C‐band. In addition to the different types of line shapes, the extinction ratio can also be enhanced by dynamically tuning the coupling position. This research provides an efficient approach to manipulate the transmission spectra of the Fano resonance, which is of great importance in promoting its further applications on integrated photonics platforms. [ABSTRACT FROM AUTHOR]

The investigation and development of innovative micro‐ and nanolasers using transition metal dichalcogenide (TMDC) monolayers as active materials is attracting considerable attention due to their unique electrical, mechanical, and optical properties. In this report, the fabrication of photonic‐defect microcavities that are self‐assembled and integrated into a dielectric distributed Bragg reflector structure that fully encapsulates a monolayer of tungsten diselenide (WSe2${\rm WSe}_2$) is detailed. The encapsulation process of the WSe2${\rm WSe}_2$ monolayer with hexagonal boron nitride generates air bubbles that induce parabolic photonic defects in the microcavity. These defects lead to a tight diameter‐dependent three‐dimensional optical confinement, which is confirmed by experimental studies and numerical simulations. In addition, a significant nonlinearity in the input‐output characteristics and excitation‐power‐dependent linewidth narrowing is observed in the resonators, indicating laser operation, which is verified by photon autocorrelation measurements. The photonic‐defect cavities are all formed on a single monolayer sample, suggesting potential advantages for multi‐wavelength emission photonic applications and facilitating TMDC‐based prestructured photonic‐defect microlasers for large‐scale fabrication. [ABSTRACT FROM AUTHOR]

Chirality, one of the universal phenomena in physics, forms the playground for fascinating phenomena in modern electromagnetism and industrial applications. Within the rapidly advancing technologies of integrated optoelectronic and all‐optical devices, controlling the light flow on a chip using optical chiral modes emerges as a crucial topic, which implies numerous counterintuitive chiroptical effects such as unidirectional emission, magnetic‐free non‐reciprocity, chiral switching, and enhanced sensitivity. Here strong yet reconfigurable mode chirality is demonstrated in integrated silicon‐based spiral microring resonators. Leveraging the adjustable azimuthal positions of two spiral edges as asymmetric local scatterers, the inter‐modal coupling can be manipulated, which bypasses the requirement of external off‐chip components in conventional schemes. Besides, an integrated phase shifter enables electrical reconfiguration of the non‐Hermiticity toward or away from exceptional points. Experimental results reveal post‐fabrication reconfiguration with a sign‐reversible chirality and chirality‐induced suppression of backscattering down to −24 dB. By virtue of demonstrations using standard silicon photonics foundry services, the findings provide a new design framework of microresonators as a building block for integrated chiral photonics in both classical and quantum regimes. [ABSTRACT FROM AUTHOR]

This paper studies wave localization in chains of finitely many resonators. There is an extensive theory predicting the existence of localized modes induced by defects in infinitely periodic systems. This work extends these principles to finite‐sized systems. We consider one‐dimensional, finite systems of subwavelength resonators arranged in dimers that have a geometric defect in the structure. This is a classical wave analog of the Su–Schrieffer–Heeger model. We prove the existence of a spectral gap for defectless finite dimer structures and find a direct relationship between eigenvalues being within the spectral gap and the localization of their associated eigenmode. Then, for sufficiently large‐size systems, we show the existence and uniqueness of an eigenvalue in the gap in the defect structure, proving the existence of a unique localized interface mode. To the best of our knowledge, our method, based on Chebyshev polynomials, is the first to characterize quantitatively the localized interface modes in systems of finitely many resonators. [ABSTRACT FROM AUTHOR]

This article presented a four-element dual-band linear phased antenna array operating at sub-6 GHz. The single-element antenna was designed by mounting a double-negative single- layered Complementary Split Ring Resonator (SL-CSRR) on the patch and grounding with a rectangular slot and four SL-CSRR's array; it was resonated at dual bands 3.43–3.56 GHz and 4.93–5.75 GHz and got size shrinkage of 80.45% with dimensions 0.35λx0.35λx0.028λ mm3. The proposed phased array antenna was resonated in 3.42–3.57 GHz and 4.86–5.74 GHz with central frequencies 3.49 GHz and 5.18 GHz, respectively, with respect to −10 dB impedance bandwidth. It was dimensioned with 0.35λx2.42λx0.028λ mm3. The isolation of > 16 dB, ECC < 0.1, DG ~ 10 dB, CCL < 0.15bits/s/Hz and MEG<-6 dB were achieved. The maximum gain of 8.4dBi and 10.4dBi and maximum efficiency of 81.14%, and 99.12% were achieved over the two resonated bands, respectively. The array antenna excited initially with 0° phase difference was radiated bi-directional beam focused to 0° and 180° in the pattern like a broadside array and with the change of phase difference, the structure capable to focus the beam to ± 90° like end-fire array at 3.49 GHz and it was capable to steer the beam to ± 48.6° at 5.18 GHz. These results demonstrated that the proposed phased array antenna is a good candidate to provide services at base stations for 5 G sub-6 GHz applications. The prototypes of the single-element antenna and four-element phased array antennae were fabricated and tested. The matching of simulation results with measurement one has a good commitment to similarity. [ABSTRACT FROM AUTHOR]

A multiband microstrip antenna integrated with an electromagnetic bandgap (EBG) structure operating at WLAN and WiMAX frequencies is proposed for wearable applications. The antenna consists of a circular patch surrounded by the ground plane, separated by a ring slot. The size of the integrated antenna has been significantly reduced to 0.28 $\lambda $ λ ×0.28 $\lambda $ λ and thickness of 0.024 $\lambda $ λ. A single-layered planar groundless EBG structure has been designed to suppress the wideband of frequencies from 2.2 to 5.4 GHz. An equivalent circuit model is presented to explain the zero-degree reflection phase of the EBG. Integration of the antenna with the EBG structure and a simple resonator bestows operating bands at 2.45 and 5.2, 5.5 and 5.8 GHz with significantly low back radiation. The gain and directivity of the antenna have been increased to 5.41 dB and 6.2 dB, respectively. The Specific Absorption Rate (SAR) of the antenna has been reduced to 0.0859W/kg, which is significantly lower than the admissible SAR value recommended by the Federal Communications Commission (FCC). The antenna is fabricated on an FR4 substrate, and its measured radiation characteristics are well matched to the simulated one. [ABSTRACT FROM AUTHOR]

Self-powered wireless sensing system is particularly suitable for applications in intelligent manufacturing, smart healthcare etc. as it does not require an external power source. Triboelectric nanogenerator (TENG) is an emerging energy harvester that can be used to power self-powered wireless sensors. The latest achievement in this area is the instantaneous self-powered wireless sensor, where the electric energy generated by the TENG is injected directly into the inductor-capacitor (LC) resonator to generate a decaying oscillating signal with encoded sensing information. However, the frequency is lower (typically < 5 MHz) and the signal transmission distance is short (< 3 m) limited by the near-field magnetic coupling, restricting its widespread applications. In this research, we propose a self-powered long-distance wireless sensing platform which utilizes a surface acoustic wave (SAW) resonator based radio-frequency oscillator to convert TENG energy into a high frequency signal with sensing information encoded. With this system, the sensing signal can be easily transmitted through the antenna for long distance. An optimized system is designed and conditional influences are fully investigated. Results show this self-powered wireless sensor system can perform wireless sensing for force, temperature and vibration at a distance up to 50 m. [ABSTRACT FROM AUTHOR]

A full‐color colorimetric humidity sensor with high brightness is proposed by using a hetero‐structured dielectric film in a metal‐insulator‐metal (MIM) resonator. A humidity‐responsive polymer is designed to graft on top of a metal‐organic frameworks (MOFs) thin film (MOFs‐Polymer) as insulator layer in the resonator. Programmable tuning of reflected color is achieved by controlling the polymer thicknesses, and finite difference time domain simulation of light‐matter interactions at subwavelength scales proves the dependence of the reflected wavelength on dielectric layer thickness of the resonator. Vivid full‐color changing is realized during tracking humidity process due to swelling of the stimuli‐responsive polymer. Ultrafast response (≈0.75 s) is achieved for tracking trace H2O from H2O/methanol mixture, which is ≈104 faster than that of the pure polymer‐based MIM resonator. Meanwhile, the study observes significant spectral redshift because the porous MOFs film facilitates the preconcentration of external stimulus and improves the detection sensitivity of the resonator. Further, double‐channel anti‐counterfeiting multiplexing imaging is devised on the MIM resonator by photomask technology. Patterned encoding for security label is achieved on the MIM resonator by engineering humidity‐tunable pixels of Au/MOFs‐Polymer/Au and humidity‐invalid pixels of Au/MOFs/Au. [ABSTRACT FROM AUTHOR]

We study the mechanical response of bulk CrSBr in temperature using a CrSBr string resonator. We observe two abrupt changes in eigenfrequency and quality factor of the resonator with decreasing temperature, a strong one around 140 K due to an antiferromagnetic phase transition, and a weaker one around 200 K possibly related to a change of spin correlations. We find that the antiferromagnetic transition persists through a temperature window of 30 K rather than showing a narrow sharp change, indicating a gradual spin transition process. In addition, the quality factor exhibits an unexpected increase during the transition, which violates the theoretical prediction. Finally, we demonstrate that in a CrSBr/SiN composite resonator, its vibrational state is sensitively affected by the constituent CrSBr layer during the magnetic phase transitions. It reveals the potential of a composite resonator in both controlling its vibration state with and probing phase transitions of its constituent materials. Our study not only enriches the details about the antiferromagnetic phase transition in CrSBr, but also opens up possibility in magnetic sensing and in situ tuning using composite mechanical resonators. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper introduces a downconverter mixer employing a modified double‐balanced Gilbert‐cell topology, designed using IHP's 0.13‐μ$$ \upmu $$m SiGe BiCMOS technology. Distinct from the conventional topology, a resonator was employed at the emitter of the transconductance stage, which enables the utilization of transconductance stage as an active balun, allowing for direct feeding of the single‐ended input without sacrificing the advantageous of the double‐balanced topology. The integration of the resonator reduces the amplitude and phase errors within the active balun segment, thereby enhancing port‐to‐port isolation. The area occupied by the resonator is approximately 1.7 times smaller than that of an RF transformer balun typically employed in conventional double‐balanced topologies. The LO and IF differential signals are converted to single‐ended ones through transformer baluns for measurement purposes. The frequencies of operation for RF, LO, and IF are 24–30, 18–24, and 6 GHz, respectively. The conversion loss is 7.7 dB at 26 GHz, with port‐to‐port isolations exceeding 35 dB. The input 1‐dB compression point is 5.7 dBm, while the circuit consumes 65‐mW power from a 3.3‐V voltage supply. Excluding the pads, the active area of the design spans 1 mm2. [ABSTRACT FROM AUTHOR]

It is known that the electromagnetic vacuum is responsible for the Lamb shift, which is a crucial phenomenon in quantum electrodynamics (QED). In circuit QED, the readout or bus resonators that are dispersively coupled can result in a significant Lamb shift of the qubit. However, previous approaches or proposals for controlling the Lamb shift in circuit QED demand overheads in circuit designs or non-perturbative renormalization of the system's eigenbases, which can impose formidable limitations. In this work, we propose and demonstrate an all-microwave method for controlling the Lamb shift of fixed-frequency transmons. We employ the drive-induced longitudinal coupling between the transmon and resonator. By simply using an off-resonant monochromatic drive near the resonator frequency, we can control the net Lamb shift up to ±30 MHz and engineer it to zero with the drive-induced longitudinal coupling without facing the aforementioned challenges. Our work establishes an efficient way of engineering the fundamental effects of the electromagnetic vacuum and provides greater flexibility in non-parametric frequency controls of multilevel systems. Engineering the Lamb shifts of superconducting qubits opens new opportunities in resonant frequency tunings and other applications. Here, the authors devise and demonstrate an all-microwave approach that can be utilized with fixed-frequency superconducting qubits. [ABSTRACT FROM AUTHOR]

VO2 is a promising phase change material offering a large contrast of electric, thermal, and optical properties when transitioning from semiconductor to metallic phase. Here we show that a hybrid metamaterial obtained by proper combination of a VO2 layer and a nanodisk gold array provides a tunable plasmonic gap resonance in the infrared range. Specifically, we have designed and fabricated a metal–insulator-metal gap resonance by inserting sub-wavelength VO2 film between a flat gold layer and a gold nanodisk resonator array. The resonance of the hybrid metamaterial is centered in the useful 3–5 μm range when VO2 is in its semiconductor state. The experimental study highlights a monotonical spectral tuning of the resonance when increasing temperature up to 50 °C above the room temperature, providing a continuous resonance shift of almost 1 μm in the mid-infrared range. Wavelength range and intensity tunability can be further optimized by modifying the thicknesses of the layers and metamaterial parameters. [ABSTRACT FROM AUTHOR]

In this paper, a miniaturized microstrip diplexer designed on an FR4 substrate material is presented. The diplexer operates at 2.4 and 3.5 GHz, responding to the demands of 5G and WiMAX applications, respectively. It consists of two distinct bandpass filters (BPFs) formed using the meandrous line, which are combined using a coupled-junction. An electromagnetic (EM) simulator was used to characterize the frequency responses of the designed diplexer. The results show that the proposed diplexer exhibits excellent isolation, exceeding 28.5 dB throughout the operating frequency range. Additionally, the passband insertion losses are approximately 1 dB, while the return losses measure around 39 and 57 dB for the both channels, respectively. Furthermore, the manufactured diplexer is compact with final dimensions of 28.5 × 20 mm2. These results confirm the suitability of the proposed diplexer for the intended applications. [ABSTRACT FROM AUTHOR]

This paper presents a frequency reconfigurable filtenna for efficiently switching between ultra-wideband (UWB) and 5G-n77 band. The filter section with the UWB state of operation is realised by a stepped impedance open stub loaded at the middle of a stepped impedance resonator. Switching to 5G-n77 band is accomplished by appending two open-circuited uniform impedance stubs to the UWB filter section through PIN diodes. The antenna section is coplanar waveguide (CPW) fed and is based on a quasi-self-complementary design with a half- hexagonal-shaped radiator. The microstrip to CPW transition is realised by connecting the ground planes through vias. The overall size of the filtering antenna is 18.5 mm × 57 mm. The filtering antenna has stable radiation patterns with good agreement between simulated and measured results. The peak gain in 5G-n77 band and UWB band is 4 dBi. [ABSTRACT FROM AUTHOR]

This paper presents, a novel and simple resonator structure based second order triple band waveguide band-pass filter with adjustable centre frequency and 3-dB bandwidth. The planar insert consists of a circular shape etched part in which three stubs is placed. Three asymmetrical stub length and width are used to control three resonant frequency and 3-dB bandwidth independently. The insert is placed into the transverse plane of the WR-90 waveguide. To achieve second order band-pass filter response two symmetrical resonators is placed at an optimised distance of 8.99 mm. Simulation and optimisation analysis of the proposed filter is carried-out using CST Studio Suite (v23). To validate the 3D model, planar insert and WR-90 waveguide are fabricated individually and inserted manually. The measured results shows triple band bandpass filter characteristics having centre frequencies f01 = 8.44 GHz, f02 = 9.98 GHz and f03 = 11.51 GHz with 3-dB bandwidth of 0.78, 0.12 and 0.3 GHz. The insertion loss of the measured filter is 0.35, 0.8 and 0.55 dB. The in band return loss of the proposed filter are better than 12 dB. [ABSTRACT FROM AUTHOR]

Micro and nanomechanical devices offer enhanced sensing capabilities for detecting biological and chemical small molecules. However, miniaturization necessitates advanced fabrication processes and complex measurement systems, hindering routine sensor analysis. While alternative methods like 3D printing show promise, challenges such as low device resolution persist due to intrinsic damping of polymer inks. In this study, an array of micrometric pillar resonators is fabricated in Ti6Al4 V alloy using additive manufacturing based on laser powder bed fusion technology. These metallic nanomechanical resonators exhibit a very high quality factor with minimal difference between air and vacuum measurements due to low intrinsic damping. Furthermore, titania nanotubes grown on the pillars via anodic oxidation heighten sensitivity for molecular dye degradation evaluation. Leveraging the weak coupling phenomenon among the pillars in the array, these devices facilitate large‐scale parallelized measurements, here demonstrated with real‐time analysis of dye degradation process. This approach to creating mass sensing devices via metallic additive manufacturing can usher in a new generation of highly performing resonating sensor arrays, offering a cost‐effective and efficient alternative to traditional silicon microfabrication methods. [ABSTRACT FROM AUTHOR]

The working mechanism of resonant sensors is based on tracking the frequency shift in the linear vibration range. Contrary to the conventional paradigm, in this paper, we show that by tracking the dramatic frequency shift of the saddle-node bifurcation on the nonlinear parametric isolated branches in response to external forces, we can dramatically boost the sensitivity of MEMS force sensors. Specifically, we first theoretically and experimentally investigate the double hysteresis phenomena of a parametrically driven micromechanical resonator under the interaction of intrinsic nonlinearities and direct external drive. We demonstrate that the double hysteresis is caused by symmetry breaking in the phase states. The frequency response undergoes an additional amplitude jump from the symmetry-breaking-induced parametric isolated branch to the main branch, resulting in double hysteresis in the frequency domain. We further demonstrate that significant force sensitivity enhancement can be achieved by monitoring the dramatic frequency shift of the saddle-node bifurcations on the parametric isolated branches before the bifurcations annihilate. Based on the sensitivity enhancement effect, we propose a new sensing scheme which employs the frequency of the top saddle-node bifurcation in the parametric isolated branches as an output metric to quantify external forces. The concept is verified on a resonant MEMS charge sensor. A sensitivity of up to 39.5 ppm/fC is achieved, significantly surpassing the state-of-the-art resonant charge sensors. This work provides a new mechanism for developing force sensors of high sensitivity. [ABSTRACT FROM AUTHOR]

Vibration isolation metamaterial barrier has been extensively studied in mitigating the damage induced by vibration, while a deeper understanding of the vibration isolation characteristics based on laboratory experiments is still lacking. In this work, a locally resonant metamaterial barrier is proposed, and a large‐scale laboratory experiment was first designed to investigate the isolation mechanism of the proposed metamaterial barrier. The metamaterial vibration isolation barrier is assembled by arraying 5 × 5 resonators. To better explain the observations in experiments and unveil the underlying isolation mechanism, COMSOL Multiphysics was also employed to simulate the laboratory experiment. Subsequently, the vibration isolation effect is quantitatively analyzed by analyzing the acceleration amplitude reduction spectrum (ARS) of the ground surface. The vibration isolation mechanism is discussed by monitoring the acceleration field around the metamaterial barrier. The results indicate that two significant locally resonant attenuation domains are observed, which are induced by the first‐order and second‐order vertical resonance frequencies of the metamaterial. Another experimental scheme that simultaneously monitored the acceleration of the mass block and the bottom of resonators was implemented to investigate vibration in the resonator. The vibration energy distribution on the mass block and the bottom of the resonator is found to depend significantly on the vibration frequency. When the frequency is lower than a certain frequency, the locally resonant is dominant. Otherwise, the geometric scattering is dominant. The vibration isolation mechanism of the locally resonance metamaterial was investigated by laboratory experiments and provided an effective solving path for isolating the low‐frequency vibration. [ABSTRACT FROM AUTHOR]

Tacticity is long known as a significant contributor in changing the chemical and mechanical properties of the polymers drastically. This study explores mechanism of bandgap formation in elastic mechanical metastructures designed with a focus on tacticity. We introduce metabeams, comprising a primary slender beam embedded with short secondary beams featuring end masses at their tips. The investigation delves into the numerically simulated vibration characteristics of metabeams using finite element analysis, with a subsequent comparison to experimental results for fabricated metabeams. Employing a unit-cell design approach that manipulates spatial and physical parameters, we explore a wide range of uniform and non-uniform metabeam configurations based on the distance between secondary beams and distribution of local resonators as per tacticity. Hence, drawing inspiration from tacticity, we extend our investigation to isotactic and syndiotactic metabeams, altering physical parameters (mass) within the unit cell for both configurations. The strategic distribution of end masses on attached secondary beams introduces unique characteristics to isotactic and syndiotactic metabeams, allowing for the modulation of bandgaps without altering the natural frequencies of the resonators in symmetric and anti-symmetric metabeam designs. Our research demonstrates, incorporating tacticity in metabeam design offers a novel and unconventional approach to modulate the bandgap formation mechanism. [ABSTRACT FROM AUTHOR]

Broadband impedance-matched Josephson parametric amplifiers are key components for high-fidelity single-shot multi-qubit readout. Nowadays, several types of impedance matched parametric amplifiers have been proposed: the first is an impedance-matched parametric amplifier based on a Klopfenstein taper, and the second is the impedance-matched parametric amplifier based on auxiliary resonators. Here, we present the quantum-limited 3-wave-mixing lumped-element SNAIL parametric amplifier with two-pole impedance matching transformer. A two-pole Chebyshev matching network with shunted resonators is based on parallel-plate capacitors and superconducting planar coil. Operating in a flux-pumped mode, we experimentally demonstrate an average gain of 15 dB across a 600 MHz bandwidth, along with an average saturation power of −107 dBm and quantum-limited noise temperature. [ABSTRACT FROM AUTHOR]