Pair Of Resonators Research Articles

Perturbation influence of a parity-time optical resonator pair

In this article, we study the perturbation influence on a parity-time (PT) optical resonator pair. Critical characteristics of this type of device, including the sensitivity, dynamic range, and robustness, are formulated and discussed systematically. Through the study of three operational phase regimes, the exceptional point (EP), the PT-symmetry, and symmetric broken phases, we find that the optimal range of the PT resonator pair prefers to be at the PT-broken phase regime near the EP state, considering both the robustness and sensitivity factors. Furthermore, we also find that the device’s dynamic range is proportional to the temporal coupling coefficient κ and gain/loss coefficient γ, which means increasing the coupling and gain/loss coefficients will enable a broader dynamic response. Additionally, we further suggest that: (1) to enhance the sensitivity, γ should be no less than 0.94κ; (2) to achieve a large gain factor of a ⩾ 2, γ must satisfy 0.995κ ⩽ γ ⩽ 1.06κ; and (3) to obtain a larger dynamic range, γ needs to be closer to κ. In particular, for γ = κ, i.e., the EP case, the largest dynamic range of ɛ ⩽ 0.24κ is obtained.

A three‐state diplexer design using stub‐loaded resonator pairs

This letter presents a three-state diplexer design. By employing one port as the input while the other two as the output, the proposed circuit functions as three diplexers operating at different passbands. Owing to the planar stub-loaded resonator pair, two transmission zeros are generated at passband edges, ensuring sharp frequency selectivity for each filter passband. In addition, an asymmetrical feed scheme is adopted based on the discriminating coupling method, resulting in two other controllable out-of-band transmission zeros. These zeros are essential for isolation improvement between the three diplexer operations. For demonstration, the three-state diplexer is implemented. Compact size and measured isolation of more than 27.6 dB between the three states are obtained.

Extending the Spin Excitation Lifetime of a Magnetic Molecule on a Proximitized Superconductor.

Molecular spins on surfaces potentially used in quantum information processing and data storage require long spin excitation lifetimes. Normally, coupling of the molecular spin with the conduction electrons of metallic surfaces causes fast relaxation of spin excitations. However, the presence of superconducting pairing effects in the substrate can protect the excited spin from decaying. In this work, we show that a proximity-induced superconducting gold film can sustain spin excitations of a FeTPP-Cl molecule for more than 80 ns. This long value was determined by studying inelastic spin excitations of the S = 5/2 multiplet of FeTPP-Cl on Au films over V(100) using scanning tunneling spectroscopy. The spin lifetime decreases with increasing film thickness, along with the decrease of the effective superconducting gap. Our results elucidate the use of proximitized gold electrodes for addressing quantum spins on surfaces, envisioning new routes for tuning the value of their spin lifetime.

A balanced tri-band BPF with high selectivity based on ASSLR

Abstract In this paper, a balanced second-order tri-band bandpass filter (BPF) with high selectivity is proposed. Three differential-mode (DM) passbands are formed by applying one pair of asymmetric short stub-loaded resonators (ASSLRs) and uniform impedance resonators (UIRs) into the design. Meanwhile, the frequencies and bandwidths of the DM passbands can be quasi-independently controlled by the lengths of resonators and the gaps between them. In addition, broadband common-mode (CM) suppression is achieved intrinsically without affecting the DM parts based on the U-type balanced stepped-impedance microstrip-slotline transition (BSIMST) structures, thereby simplifying the design procedure significantly. In order to validate the practicability, a balanced tri-band BPF operating at 1.8, 3.5 and 4.45 GHz is fabricated and designed. A good agreement between the simulated and measured results is observed.

Analogue of electromagnetically induced transparency inspired by bound states in the continuum and toroidal dipolar response in all-dielectric metasurfaces

Optical resonance cavity with high Q-factor is a paramount indicator of high-performance photonic devices. In this article, we present an all-dielectric metasurface composed of hollow cylindrical tetrameric clusters in the near-infrared region. Combining with the bound states in the continuum (BICs) theory, a distinct analogue of electromagnetically induced transparency (EIT) resonance arises. The squared inverse relationship between the Q-factor and the asymmetric parameters is calculated to corroborate the excitation of the quasi-BIC EIT pattern. By observing the distribution characteristics of the electromagnetic field in resonant mode and performing a multipole decomposition, the proposed metasurface can support magnetic dipole (MD), electric quadrupole (EQ) and toroidal dipole (TD) response simultaneously, which exhibits remarkable field confinement capability. The geometric parameters are adjusted to observe the variation of the dipole scattering energy. Subsequently, the transmission spectrum shows a peculiar pair of TD resonances, which possess remarkably dependence on polarization. The sensitivity and figure of merit (FOM) values of the sensor can reach 430 nm/RIU and 483 RIU−1. It is believed that the proposed metasurface may provide a constructive approach for slow light devices, high-performance sensors and polarization independent devices.

Reconfigurable Voltage Controlled Single-Band and Multiband Bandstop Filters With High Selectivity and Wide Tuning Range

This paper presents fully reconfigurable voltage controlled single-band and multiband bandstop filters (BSFs). Distributed coupling half-wavelength resonators and multimode resonators (MMRs) loaded by varactor diodes are applied to design the proposed fully reconfigurable BSFs. A MMR is equivalent to multiple single-mode resonators and its resonant characteristics are analyzed based on the even-odd-mode method. The frequencies, bandwidths, and the number of stopbands can be independently controlled by bias voltages. The frequency and bandwidth tuning ranges can be adjusted by geometrical dimensions. Moreover, the stopband suppression level is proportional to the number of resonators. For demonstration, six pairs of half-wavelength resonators with two sets of sizes are applied to design a fully reconfigurable BSF with single, dual, triple, and quadruple stopbands. Then, three pairs of MMRs with a uniform size are applied to design a fully reconfigurable BSF with single and dual stopbands. The proposed BSFs have merits of high selectivity, wide frequency and bandwidth tuning ranges, independent controls of frequencies and bandwidths, and reconfigurable number of stopbands.

High sensitivity metal-insulator-metal sensor based on ring-hexagonal resonator with a couple of square cavities connected

The necessity for cheaper and more efficient sensors has been the main motivation for the use of Metal-Insulator-Metal (MIM) sensors. In this paper, a micro-dimensional refractive index MIM sensor based on surface plasmon polaritons is presented. This sensor has a ring-hexagonal resonator and a pair of squares-ring resonators that are connected to each other. For the proposed structure, magnetic field profile, transmission spectrum, and important sensor parameters such as sensitivity are obtained through the finite-difference time-domain (FDTD) method. By optimizing the dimensions of the resonators, we achieved a sensitivity equivalent to 2115 nm/RIU in the first mode and 2180 nm/RIU in the second mode. The FOM values for the first and second modes were 118.25 RIU−1 and 120.208 RIU−1, respectively. The results show that the ring-hexagonal resonator significantly improves the sensor parameters in both modes. These enhancements can be considered unique due to the simple structure presented and as a result the reduction of construction costs.

Electron-positron pairs and radioactive nuclei production by irradiation of high-Z target with γ -photon flash generated by an ultra-intense laser in the λ3 regime

This paper studies the interaction of laser-driven $\ensuremath{\gamma}$ photons and high-energy charged particles with high-Z targets through Monte Carlo simulations. The interacting particles are taken from particle-in-cell simulations of the interaction of a tightly focused ultra-intense laser pulse with a titanium target. Lead is chosen as the secondary high-Z target because of its high cross-section of the giant dipole resonance and electron-positron pair production. The results reveal an ultra-short, ultra-relativistic collimated positron population and their energy spectra, angular distribution, and temporal profile are found. We investigate the target thickness dependence of the resulting total numbers and total kinetic energies of various particle species emitted from the lead target irradiated with laser-generated $\ensuremath{\gamma}$ photons and charged particles separately. We plot the charts of residual high-Z nuclides generated by irradiation of the lead target. Because of the short pulse duration, the $\ensuremath{\gamma}$ photon, electron-positron, and neutron sources could find applications in material science, nuclear physics, laboratory astrophysics, and as injectors in laser-based accelerators of charged particles.

Search for resonant pair production of Higgs bosons in the bb¯bb¯ final state using pp collisions at s=13 TeV with the ATLAS detector

A search for resonant Higgs boson pair production in the $b\bar{b}b\bar{b}$ final state is presented. The analysis uses 126-139 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets or as individual large-radius jets. Spin-0 and spin-2 benchmark signal models are considered, both of which correspond to resonant $HH$ production via gluon$-$gluon fusion. The data are consistent with Standard Model predictions. Upper limits are set on the production cross-section times branching ratio to Higgs boson pairs of a new resonance in the mass range from 251 GeV to 5 TeV.

EBG and SRR Loaded Triple Band Notched UWB Antenna

A compact triple band notched ultra-wideband (UWB) monopole antenna is presented in this paper. Split Ring Resonator (SRR) structure is exploited in various forms like Complementary Split Ring Resonator (CSRR), Split Ring Resonator Pair (SRRP) and CSRR on Electromagnetic Band Gap (EBG) structure to produce triple band notched characteristics in UWB spectrum. The proposed antenna produces triple band notched functions with integration of all three types of SRR on primary antenna. The parametric analysis of each form of SRR is presented along with their current distribution effects on triple band notched antenna. The proposed antenna prototype is fabricated and measured results are also compared with simulated one to understand the discrepancies. The measured and simulated results are presented to investigate the band notching characteristics of suggested antenna in terms of VSWR and radiation characteristics.

Embroidered Textile Frequency-Splitting Sensor Based on Stepped-Impedance Resonators

This paper presents an embroidered textile frequency-splitting microwave sensor based on a pair of identical stepped-impedance resonators (SIRs) loading a microstrip transmission line. The sensor is implemented by means of conductive threads. The sensing region of the proposed structure is the capacitive square patch of one of the SIRs. If such region is kept unaltered, the structure is symmetric, and the frequency response (transmission coefficient) exhibits a single transmission zero. However, if symmetry is broken (e.g., through liquid absorption in the sensing region), the frequency response of the proposed sensor exhibits two transmission zeros (frequency splitting). The difference (in frequency and magnitude) between such zeros (or notches) is intimately related to the dielectric properties of the absorbed liquids to be sensed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/$ </tex-math></inline-formula> detected. The proposed sensing structure is applied to the detection of deionized (DI) water absorption, and to the quantification of the number of DI water drops. The maximum measured sensitivity is found to be 2.70 MHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/ \mu \text{l}$ </tex-math></inline-formula> and 0.03 dB <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/ \mu \text{l}$ </tex-math></inline-formula> for the incremental frequency and incremental magnitude of the notches.

Benchmark planes for Higgs-to-Higgs decays in the NMSSM

We present benchmark planes (or lines) with cross sections via gluon fusion for the processes Hrightarrow h+H_{S}, resonant Higgs pair and triple Higgs production, A rightarrow h+(A_S rightarrow gamma gamma ), A rightarrow Z+ h and A rightarrow Z+ H_{S} within the Next-to-Minimal Supersymmetric Standard Model. Moreover we propose new searches for Hrightarrow h+(H_{S} rightarrow t{bar{t}}), A rightarrow Z+ (H_{S}rightarrow h+h) and A rightarrow Z+ (H_{S}rightarrow t{bar{t}}) for which possible cross sections are given. These allow the experimental collaborations to verify in the future which search channels cover yet unexplored regions of the parameter space. Expressions for the dominant contributions to trilinear Higgs couplings and Higgs–Z couplings are discussed which allow to identify the dominant processes contributing to a given final state.

Quantum state preparation and tomography of entangled mechanical resonators.

Precisely engineered mechanical oscillators keep time, filter signals and sense motion, making them an indispensable part of the technological landscape of today. These unique capabilities motivate bringing mechanical devices into the quantum domain by interfacing them with engineered quantum circuits. Proposals to combine microwave-frequency mechanical resonators with superconducting devices suggest the possibility of powerful quantum acoustic processors1-3. Meanwhile, experiments in several mechanical systems have demonstrated quantum state control and readout4,5, phonon number resolution6,7 and phonon-mediated qubit-qubit interactions8,9. At present, these acoustic platforms lack processors capable of controlling the quantum states of several mechanical oscillators with a single qubit and the rapid quantum non-demolition measurements of mechanical states needed for error correction. Here we use a superconducting qubit to control and read out the quantum state of a pair of nanomechanical resonators. Our device is capable of fast qubit-mechanics swap operations, which we use to deterministically manipulate the mechanical states. By placing the qubit into the strong dispersive regime with both mechanical resonators simultaneously, we determine the phonon number distributions of the resonators by means of Ramsey measurements. Finally, we present quantum tomography of the prepared nonclassical and entangled mechanical states. Our result represents a concrete step towards feedback-based operation of a quantum acoustic processor.

Formation of Spontaneous Density-Wave Patterns in dc Driven Lattices

Driving a many-body system out of equilibrium induces phenomena such as the emergence and decay of transient states, which can manifest itself as pattern and domain formation. The understanding of these phenomena expands the scope of established thermodynamics into the out-of-equilibrium domain. Here, we experimentally and theoretically study the out-of-equilibrium dynamics of a bosonic lattice model subjected to a strong DC field, realized as ultracold atoms in a strongly tilted triangular optical lattice. We observe the emergence of pronounced density wave patterns -- which spontaneously break the underlying lattice symmetry -- using a novel single-shot imaging technique with two-dimensional single-site resolution in three-dimensional systems, which also resolves the domain structure. Our study suggests that the short-time dynamics arises from resonant pair tunneling processes within an effective description of the tilted Hubbard model. More broadly, we establish the far out-of-equilibrium regime of lattice models subjected to a strong DC field, as an exemplary and paradigmatic scenario for transient pattern formation.

Dual-band electromagnetically induced transparent metamaterial with slow light effect and energy storage

The realization of electromagnetically induced transparency (EIT) on metamaterials has special properties, such as strong slow-light, frequency-selection and so on, which have allowed EIT to be widely used in the fields of slow-light, optical storages and filters. In this paper, a metamaterial with two pairs of split ring resonators and one cut-wire is designed to achieve dual-band EIT effect at 0.5–2.14 GHz and 0.4–2.10 GHz with independently tunable bandwidths of 1.64 GHz and 2.7 GHz, respectively. The coupled Lorentz model is adopted to principally study the coupling characteristics between dark and bright modes. It is shown that the coupling strength between the dark and bright modes could be modulated by the coupling distance, which make the dual-band transparent window could be independently modulated by only changing the coupling distance between the bright and dark mode. The group delay and energy storage are also simulated by setting the Gaussian pulse signal passing through the EIT structure. The results show that the group delay of the designed EIT structure is 16.9 times that of the same thickness of dielectric material. The manufactured metamaterial is tested in a microwave anechoic chamber. The experimental and theoretical results are well consistent. These results could be beneficial for the development of EIT research toward some up-and-coming novel slow-light, optical storage, sensor and optical filter applications.

Two-port network spiral type asymmetric absorption system

This paper presents a resonator with a variable helical structure that induces a change in the internal impedance of the resonator, which can improve the performance of the resonator. This resonator structure achieves an asymmetric absorption mechanism of acoustic waves by coupling a pair of Helmholtz resonators with the same coupling mode in parallel in a two-port acoustic duct. Theoretical analysis, numerical simulations, and experimental measurements confirm that the acoustic energy is almost completely absorbed (97.4%) at 287.5 Hz. By designing the acoustic “soft” boundary, the system absorbs acoustic energy when the acoustic wave is incident from one side and mostly reflects when the acoustic wave is incident from the other side. These two different absorption patterns are caused by the impedance matching/mismatch between the two sides of the system, respectively. Consequently, the asymmetric absorption system at low frequencies achieves a near-perfect absorption of acoustic energy. Asymmetric absorption at broadband and multi-band is obtained for different cases. The asymmetric design in this paper improves the active control of noise cancellation in a two-port system and allows for a more diverse use of absorption devices.

Sculpting the circumbinary planet size distribution through resonant interactions with companion planets

ABSTRACTResonant locking of two planets is an expected outcome of convergent disc migration. The planets subsequently migrate together as a resonant pair. In the context of circumbinary planets, the disc is truncated internally by the binary. If there were only a single planet, then this inner disc edge would provide a natural parking location. However, for two planets migrating together in resonance there will be a tension between the inner planet stopping at the disc edge and the outer planet continuing to be torqued inwards. In this paper, we study this effect, showing that the outcome is a function of the planet–planet mass ratio. Smaller outer planets tend to be parked in a stable exterior 2:1 or 3:2 resonance with the inner planet, which remains near the disc edge. Equal or larger mass outer planets tend to push the inner planet past the disc edge and too close to the binary, causing it to be ejected or sometimes flipped to an exterior orbit. Our simulations show that this process may explain an observed dearth of small (&amp;lt;3 R⊕) circumbinary planets, since small planets are frequently ejected or left on long-period orbits, for which transit detection is less likely. This may also be an effective mechanism for producing free-floating planets and interstellar interlopers like ‘Oumuamua.

Resonant nonlinear pairs in the axiverse and their late-time direct and astrophysical signatures

A generic low-energy prediction of string theory is the existence of a large collection of axions, commonly known as a string axiverse. Axions also have a natural cosmological production mechanism, vacuum misalignment, making them well-motivated dark matter (DM) candidates. Much work on axion production has considered the case of a single free axion, but in a realistic axiverse, string axions are expected to be distributed densely over many orders of magnitude in mass, and to interact with one another through their joint potential. In this paper, we show that non-linearities in this potential lead to a new type of resonant energy transfer between axions with nearby masses. This resonance generically transfers energy from axions with larger decay constants to those with smaller decay constants, and leads to a multitude of signatures. These include enhanced direct detection prospects for a resonant pair comprising even a small subcomponent of dark matter, and boosted small-scale structure if the pair is the majority of DM. Near-future iterations of experiments such as ADMX and DM Radio will be sensitive to this scenario, as will astrophysical probes of DM substructure.

Asymptotic Floquet theory for first order ODEs with finite Fourier series perturbation and its applications to Floquet metamaterials

Our aim in this paper is twofold. Firstly, we develop a new asymptotic theory for Floquet exponents. We consider a linear system of differential equations with a time-periodic coefficient matrix. Assuming that the coefficient matrix depends analytically on a small parameter, we derive a full asymptotic expansion of its Floquet exponents. Based on this, we prove that only the constant order Floquet exponents of multiplicity higher than one will be perturbed linearly. The required multiplicity can be achieved via folding of the system through certain choices of the periodicity of the coefficient matrix. Secondly, we apply such an asymptotic theory for the analysis of Floquet metamaterials. We provide a characterization of asymptotic exceptional points for a pair of subwavelength resonators with time-dependent material parameters. We prove that asymptotic exceptional points are obtained if the frequency components of the perturbations fulfill a certain ratio, which is determined by the geometry of the dimer of subwavelength resonators.

A Compact Dual-Band Quasi-Elliptic Filter Based on Hybrid SIW and Microstrip Technologies

In this brief, by combining substrate integrated waveguide (SIW) and microstrip technologies, a novel dual-band filter is proposed to achieve a quasi-elliptic response for both passbands. The dual-mode characteristics of the SIW cavities, namely TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">201</sub> modes, are used to create two passbands. Different with the conventional inductive windows, two pairs of uniform impedance resonators (UIRs) with electric mutual coupling, which are etched between the two rectangular SIW cavities, are used to couple the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">201</sub> modes, respectively. Good merits are achieved in this way, including: 1) Independent coupling paths are created for TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">201</sub> modes, which would reduce the complexity of numerical optimization; 2) Since the electric couplings are generated between each pair of the UIRs, it would be easy to realize a cross coupling by only constructing inductive windows between the SIW cavities. A filter prototype with central frequencies operated at 8 GHz and 10 GHz is then designed and fabricated for validation, which shows a compact size and high selectivity with controllable transmission zeros.