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Showing papers on "Resonance published in 2020"


Journal ArticleDOI
TL;DR: In this article, a survey of tunable and active phononic crystals and metamaterials is presented, including bandgap and bandgap engineering, anomalous behaviors of wave propagation, as well as tunable manipulation of waves based on different regulation mechanisms: tunable mechanical reconfiguration and materials with multifield coupling.
Abstract: Phononic crystals (PCs) and metamaterials (MMs) can exhibit abnormal properties, even far beyond those found in nature, through artificial design of the topology or ordered structure of unit cells. This emerging class of materials has diverse application potentials in many fields. Recently, the concept of tunable PCs or MMs has been proposed to manipulate a variety of wave functions on demand. In this review, we survey recent developments in tunable and active PCs and MMs, including bandgap and bandgap engineering, anomalous behaviors of wave propagation, as well as tunable manipulation of waves based on different regulation mechanisms: tunable mechanical reconfiguration and materials with multifield coupling. We conclude by outlining future directions in the emerging field.

259 citations


Journal ArticleDOI
TL;DR: In this article, a quasi-BIC resonance was proposed to control light absorption at critical coupling through the quasi BIC resonance, and the maximum absorption of 0.5 was achieved when the radiation rate of the magnetic dipole resonance equals to the dissipate loss rate of graphene.
Abstract: Enhancing the light-matter interaction in two-dimensional (2D) materials with high $Q$ resonances in photonic structures has boosted the development of optical and photonic devices. Herein we intend to build a bridge between the radiation engineering and the bound states in the continuum (BIC), and present a general method to control light absorption at critical coupling through the quasi-BIC resonance. In a single-mode, two-port system composed of graphene, coupled with silicon nanodisk metasurfaces, the maximum absorption of 0.5 can be achieved when the radiation rate of the magnetic dipole resonance equals to the dissipate loss rate of graphene. Furthermore, the absorption bandwidth can be adjusted more than two orders of magnitude, from 0.9 nm to 94 nm, by simultaneously changing the asymmetric parameter of metasurfaces, the Fermi level, and the layer number of graphene. This work reveals the essential role of BIC in radiation engineering and provides promising strategies in controlling light absorption of 2D materials for the next-generation optical and photonic devices, e.g., light emitters, detectors, modulators, and sensors.

110 citations



Journal ArticleDOI
07 Dec 2020
TL;DR: An important entangling quantum gate is improved in this article, leading to a demonstrable increase in quantum volume, leading to an increase in the number of quantum quantum gates in the world.
Abstract: An important entangling quantum gate is significantly improved, leading to a demonstrable increase in quantum volume.

89 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated spin-wave dynamics in antiferromagnetic CrI3 bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique.
Abstract: Remarkable properties of two-dimensional (2D) layer magnetic materials, which include spin filtering in magnetic tunnel junctions and the gate control of magnetic states, were demonstrated recently1–12 Whereas these studies focused on static properties, dynamic magnetic properties, such as excitation and control of spin waves, remain elusive Here we investigate spin-wave dynamics in antiferromagnetic CrI3 bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique Monolayer WSe2 with a strong excitonic resonance was introduced on CrI3 to enhance the optical excitation of spin waves We identified subterahertz magnetic resonances under an in-plane magnetic field, from which the anisotropy and interlayer exchange fields were determined We further showed tuning of the antiferromagnetic resonances by tens of gigahertz through electrostatic gating Our results shed light on magnetic excitations and spin dynamics in 2D magnetic materials, and demonstrate their potential for applications in ultrafast data storage and processing Gating dependent laser induced spin dynamics in an antiferromagnetic bilayer are observed and explained, with implications for future spintronic applications

82 citations


Journal ArticleDOI
TL;DR: In this article, an inertial nonlinear energy sink (NES) is proposed for the elimination of multimode resonance of composite plates by an inerter to reduce the weight of the attached device.

73 citations


Journal ArticleDOI
TL;DR: In this article, a robust Fano mechanical resonance with topological protection was achieved by engineering band inversion of two different vibrating symmetries of a pillared beam that gives rise to dark and bright edge modes.
Abstract: The advances in topological condensed matter physics enable the manipulation of classic waves in different ways, such as unidirectional propagation featuring the suppression of backscattering and the robustness against impurities and disorder, making it possible to endow classical phenomena with topological properties. Fano resonance, a widely spread and basic kind of resonance, features an asymmetric line shape with an ultrahigh quality factor $Q$ that usually requires delicate designs and precise fabrication. In this work, we achieve a robust Fano mechanical resonance with topological protection by engineering band inversion of two different vibrating symmetries of a pillared beam that gives rise to dark and bright edge modes. The Fano resonance results from the constructive and destructive interferences between topological dark and bright modes. It is further demonstrated that the Fano asymmetric shape of the transmission peak and its frequency are robust against random perturbations in the pillars' position as long as the symmetry is conserved. If random perturbations break the symmetry and only band inversion is involved, the asymmetric line shape of the Fano resonance weakens until disappearing before the closure of the bulk band gap, since the excitation will couple all fundamental modes of the beam. The analysis of the robustness of Fano resonance originating from band inversion and symmetry protection reveals the nature of topological protection which can be applied to design topological high-$Q$ resonance in sensing application.

68 citations


Journal ArticleDOI
TL;DR: An experimental observation of magnon-magnon coupling in interlayer exchange coupled synthetic antiferromagnets of FeCoB/Ru/FeCoB layers finds that the coupling strength under the specified conditions is larger than the dissipation rates of both the resonance modes, indicating that a strong coupling regime is satisfied.
Abstract: We report an experimental observation of magnon-magnon coupling in interlayer exchange coupled synthetic antiferromagnets of FeCoB/Ru/FeCoB layers. An anticrossing gap of spin-wave resonance between acoustic and optic modes appears when the external magnetic field points to the direction tilted from the spin-wave propagation. The magnitude of the gap (i.e., coupling strength) can be controlled by changing the direction of the in-plane magnetic field and also enhanced by increasing the wave number of excited spin waves. We find that the coupling strength under the specified conditions is larger than the dissipation rates of both the resonance modes, indicating that a strong coupling regime is satisfied. A theoretical analysis based on the Landau-Lifshitz equation shows quantitative agreement with the experiments and indicates that the anticrossing gap appears when the exchange symmetry of two magnetizations is broken by the spin-wave excitation.

67 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported on the first demonstration of the frequency tuning and intrinsic polarization switching of film bulk acoustic resonators (FBARs), based on sputtered AlScN piezoelectric thin films with Sc/(Al + Sc) ratio of approx 30% and showed a coercive electric field at 3 MV/cm.
Abstract: This work reports on the first demonstration of the frequency tuning and intrinsic polarization switching of film bulk acoustic resonators (FBARs), based on sputtered AlScN piezoelectric thin films with Sc/(Al + Sc) ratio of approx 30% A box-like ferroelectric hysteresis behavior of 900 nm-thick Al07Sc03N sputtered films is obtained, showing a coercive electric field at ~3 MV/cm The fundamental thickness-mode resonance of the bulk acoustic wave (BAW) resonator is measured at 317 GHz frequency with an excellent electromechanical coupling coefficient ( $k_{t}^{2}$ ) of 181% The FBAR frequency response is studied, in both (i) the linear tuning regime, upon application of DC electric fields below the coercive field; as well as (ii) the polarization switching regime, upon application of electric fields above the coercive field A large linear tuning range of 215 ppm $\times \,\,\mu \text{m}$ /V is obtained in case (i), resulting from the high scandium content The series resonance frequency of the FBARs is switched ON and OFF in (ii) upon application of 350 V unipolar waveform across the Al07Sc03N thickness This is the first demonstration of the intrinsically switchable AlN-based FBARs with a large tuning range; and record high $k_{t}^{2}$ reported for AlN-based FBARs to date Furthermore, this work paves the way for realization of tunable and switchable wideband acoustic filters operating at super high frequency ranges (SHF) [2020-0203]

67 citations


Journal ArticleDOI
TL;DR: In this paper, an alternative structure design to reduce the number of resonators for multiple-band light absorption at terahertz regime is demonstrated, where five localized resonance responses in only three resonators (composed of two parallel arranged bars and a square patch) are demonstrated.
Abstract: It is quite urgent to obtain multiple-band light absorbers because they are of great important in many technology related fields. However, the realization of them is typically based on a plurality of resonators which are at least equal to the number of absorption peaks. Here an alternative structure design to reduce the number of the resonators for multiple-band light absorption at terahertz regime is demonstrated. The obtained results exhibit that penta-band terahertz light absorber with large absorption intensity and discrete frequency point is realized using five localized resonance responses in only three resonators (composed of two parallel arranged bars and a square patch). Near field patterns of the penta-band terahertz light absorber are given to clarify the absorption mechanism of each frequency point. We further explore and analyze the influence of the geometric parameters of the structure design on the performance of the penta-band light absorption.

61 citations


Journal ArticleDOI
TL;DR: In this paper, an L-shaped probe positioned underneath the finite metasurface is utilized to excite a TM leaky wave resonance and a TE surface wave resonance simultaneously for broadband operation.
Abstract: A broadband low-profile L-probe fed metasurface antenna is proposed by well exciting both transverse magnetic (TM) leaky wave and transverse electric (TE) surface wave resonances. The metasurface is composed of an array of rectangular metallic patch cells. An L-shaped probe positioned underneath the finite metasurface is utilized to excite a TM leaky wave resonance and a TE surface wave resonance simultaneously for broadband operation. The dispersion properties of the TM leaky wave and TE surface wave are used to analyze the dual resonance modes. The proposed L-probe fed metasurface antenna achieves a broad −10 dB impedance bandwidth of 34.5% with the peak gain of 10.3 dBi and the front-to-back ratio larger than 18 dB with a low profile of $0.06\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the center operating frequency.

Journal ArticleDOI
01 Jan 2020
TL;DR: In this article, the vibrational spectrum of a single crystal nano polypeptide macromolecule was analyzed using density functional theory and compared with the empirical results, and the obtained values confirm high accuracy and validity of results obtained from calculations.
Abstract: A macromolecule is a very large molecule, such as protein, commonly created by the polymerization of smaller subunits (monomers). They are typically composed of thousands of atoms or more. The most common macromolecules in biochemistry are biopolymers (nucleic acids, proteins, carbohydrates and lipids) and large non–polymeric molecules (such as lipids and macrocycles). Synthetic macromolecules include common plastics and synthetic fibers as well as experimental materials such as carbon nanotubes. Parameters such as FT –IR and Raman vibrational wavelengths and intensities for single crystal Nano polypeptide macromolecule are calculated using density functional theory and were compared with empirical results. The investigation about vibrational spectrum of cycle dimers in crystal with carboxyl groups from each molecule of acid was shown that it leads to create Hydrogen bonds for adjacent molecules. The current study aimed to investigate the possibility of simulating the empirical values. Analysis of vibrational spectrum of Nano polypeptide macromolecule is performed based on theoretical simulation and FT–IR empirical spectrum and Raman empirical spectrum using density functional theory in levels of HF/6–31G*, HF/6–31++G**, MP2/6–31G, MP2/6– 31++G**, BLYP/6–31G, BLYP/6–31++G**, B3LYP/6–31G and B3LYP6–31–HEG**. Vibration modes of methylene, carboxyl acid and phenyl cycle are separately investigated. The obtained values confirm high accuracy and validity of results obtained from calculations.

Journal ArticleDOI
TL;DR: A novel terahertz nanofilm sensor consisting of toroidal dipole bound states in the continuum (TD-BIC inspired Fano resonance metasurface) is proposed and investigated, which exhibits both the TD character and BIC feature.
Abstract: A novel terahertz nanofilm sensor consisting of toroidal dipole bound states in the continuum (TD-BIC) inspired Fano resonance metasurface is proposed and investigated, which exhibits both the TD character and BIC feature. When the mirror symmetry of the unit cell was broken, the TD resonance was excited and demonstrated by anti-aligned magnetic dipoles and calculated scattering powers and the BIC mode was verified with the quality factor satisfying the inverse square law. Combined with the amplitude difference referencing technique, the TD-BIC inspired Fano resonance was utilized for nanofilm sensing at THz frequencies for the first time. Simulation results show that the amplitude difference can be easily observed by comparing the resonance frequency shift under difference thicknesses of germanium overlayer. Moreover, by coating with a 40 nm-thick analyte overlayer, the sensitivity of amplitude difference can achieve 0.32/RIU, which is a significant value and more suitable for sensing nanofilm analytes than the traditional frequency shift method. These advantages make our proposed structure have potential applications in sensing nanofilm analytes.

Journal ArticleDOI
11 Dec 2020-Science
TL;DR: In this article, the authors demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field and demonstrate the contribution from the three dominant angular momentum projections of the collisions.
Abstract: Full control of molecular interactions, including reactive losses, would open new frontiers in quantum science. We demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field. We prepared fermionic potassium-rubidium molecules in their first excited rotational state and observed a modulation of the chemical reaction rate by three orders of magnitude as we tuned the electric field strength by a few percent across resonance. In a quasi–two-dimensional geometry, we accurately determined the contributions from the three dominant angular momentum projections of the collisions. Using the resonant features, we shielded the molecules from loss and suppressed the reaction rate by an order of magnitude below the background value, thereby realizing a long-lived sample of polar molecules in large electric fields.

Journal ArticleDOI
30 Apr 2020-Carbon
TL;DR: In this paper, an in situ electrochemical electron paramagnetic resonance (EPR) spectroscopic study of N-doped reduced graphene oxide (N-rGO) is reported with the aim of understanding the properties of this material when employed as an electrical double-layer capacitor.

Journal ArticleDOI
08 May 2020-Science
TL;DR: In this paper, state-to-state integral and differential cross sections for inelastic NO-He collisions in the 0.2 to 8.5 centimeter-1 range were obtained.
Abstract: At low energies, the quantum wave-like nature of molecular interactions results in distinctive scattering behavior, ranging from the universal Wigner laws near 0 kelvin to the occurrence of scattering resonances at higher energies. It has proven challenging to experimentally probe the individual waves underlying these phenomena. We report measurements of state-to-state integral and differential cross sections for inelastic NO-He collisions in the 0.2 to 8.5 centimeter-1 range with 0.02 centimeter-1 resolution. We studied the onset of the resonance regime by probing the lowest-lying resonance dominated by s and p waves only. The highly structured differential cross sections directly reflect the increasing number of contributing waves as the energy is increased. Only with CCSDT(Q) level of theory was it possible to reproduce our measurements.

Journal ArticleDOI
TL;DR: In this paper, the first-order antisymmetric Lamb wave (A1) mode resonator was used for front-end filtering of the 5G wireless communication in the sub-6 GHz frequency range.
Abstract: This paper reports on the demonstrations of first-order antisymmetric Lamb wave (A1) mode resonator as a new platform for front-end filtering of the fifth-generation (5G) wireless communication. The sub-6 GHz resonance in this work is achieved by employing the A1 mode in the micromachined Y-cut Lithium Niobate (LiNbO3) thin films. The spurious modes mitigation is achieved by optimizing the distribution of the electric field. The demonstrated figure-of-merit ( $\text {FoM}=Q\cdot k_{t}^{2}$ ) of 435 marks the first time that a new resonator technology with the FoMs exceeds those of surface acoustic wave (SAW) resonators and thin-film bulk acoustic resonators (FBARs) in the sub-6 GHz (1–6 GHz) frequency range. [2019-0241]

Journal ArticleDOI
TL;DR: In this paper, electron spin resonance measurements of donors in silicon at millikelvin temperatures using a superconducting LC planar micro-resonator and a Josephson parametric amplifier are reported.
Abstract: We report electron spin resonance measurements of donors in silicon at millikelvin temperatures using a superconducting LC planar micro-resonator and a Josephson parametric amplifier. The resonator includes a nanowire inductor, defining a femtoliter detection volume. Due to strain in the substrate, the donor resonance lines are heavily broadened. Single-spin to photon coupling strengths up to ∼ 3 kHz are observed. The single shot sensitivity is 120 ± 24 spins/Hahn echo, corresponding to ≈ 12 ± 3 spins / Hz for repeated acquisition.

Journal ArticleDOI
TL;DR: Excellent individual qubit tunability and long spin relaxation times make holes in germanium promising for addressable and high-fidelity spin qubits in dense two-dimensional quantum dot arrays for large-scale quantum information.
Abstract: We investigate hole spin relaxation in the single- and multihole regime in a 2 × 2 germanium quantum dot array. We find spin relaxation times T1 as high as 32 and 1.2 ms for quantum dots with single- and five-hole occupations, respectively, setting benchmarks for spin relaxation times for hole quantum dots. Furthermore, we investigate qubit addressability and electric field sensitivity by measuring resonance frequency dependence of each qubit on gate voltages. We can tune the resonance frequency over a large range for both single and multihole qubits, while simultaneously finding that the resonance frequencies are only weakly dependent on neighboring gates. In particular, the five-hole qubit resonance frequency is more than 20 times as sensitive to its corresponding plunger gate. Excellent individual qubit tunability and long spin relaxation times make holes in germanium promising for addressable and high-fidelity spin qubits in dense two-dimensional quantum dot arrays for large-scale quantum information.

Journal ArticleDOI
08 Sep 2020-Sensors
TL;DR: The obtained spectral interferometry based results demonstrate that the BSWR based sensor employing the available MDS has a similar sensitivity as the SPR based sensor, but outperforms it in the FOM.
Abstract: We report on a highly sensitive measurement of the relative humidity (RH) of moist air using both the surface plasmon resonance (SPR) and Bloch surface wave resonance (BSWR). Both resonances are resolved in the Kretschmann configuration when the wavelength interrogation method is utilized. The SPR is revealed for a multilayer plasmonic structure of SF10/Cr/Au, while the BSWR is resolved for a multilayer dielectric structure (MDS) comprising four bilayers of TiO2/SiO2 with a rough termination layer of TiO2. The SPR effect is manifested by a dip in the reflectance of a p-polarized wave, and a shift of the dip with the change in the RH, or equivalently with the change in the refractive index of moist air is revealed, giving a sensitivity in a range of 0.042–0.072 nm/%RH. The BSWR effect is manifested by a dip in the reflectance of the spectral interference of s- and p-polarized waves, which represents an effective approach in resolving the resonance with maximum depth. For the MDS under study, the BSWRs were resolved within two band gaps, and for moist air we obtained sensitivities of 0.021–0.038 nm/%RH and 0.046–0.065 nm/%RH, respectively. We also revealed that the SPR based RH measurement is with the figure of merit (FOM) up to 4.7 × 10−4 %RH−1, while BSWR based measurements have FOMs as high as 3.0 × 10−3 %RH−1 and 1.1 × 10−3 %RH−1, respectively. The obtained spectral interferometry based results demonstrate that the BSWR based sensor employing the available MDS has a similar sensitivity as the SPR based sensor, but outperforms it in the FOM. BSW based sensors employing dielectrics thus represent an effective alternative with a number of advantages, including better mechanical and chemical stability than metal films used in SPR sensing.

Journal ArticleDOI
23 Sep 2020-ACS Nano
TL;DR: A unique design of TiO2/Au/TiO2 with a combination of whispering gallery mode (WGM) resonances and SPR for efficient visible-light-driven photocatalysis is demonstrated and reveals a promising bio-approach to design highly visible light active plasmonic photocatalyst.
Abstract: The TiO2/Au nanostructure has been acknowledged as one of the most classic visible-light active photocatalysts due to the surface plasmon resonance (SPR) of Au nanoparticles. In many cases, the SPR...

Journal ArticleDOI
Yinzhu Jiang1, Hao Wang1, Shiya Wen1, Huanjun Chen1, Shaozhi Deng1 
21 Aug 2020-ACS Nano
TL;DR: The findings show the potential of the designed individual gold nanorod-monolayer WS2 heterostructure as a platform for studying the resonance coupling effect between plasmon resonance and two-dimensional excitons.
Abstract: Recently, resonance coupling between plasmonic nanocavity and two-dimensional semiconductors has attracted considerable attention. Most of the previous studies have focused on demonstrating this effect with light scattering or reflection spectroscopy, while the photoluminescence (PL) spectrum can help ascertain the underlying physics. Here, we report on the light-emitting characteristics of a monolayer WS2 flake coupled with a plasmonic gold nanorod. We construct a heterostructure by integrating an individual gold nanorod on top of a small piece of monolayer WS2, where the WS2 area is determined by the projected area of the nanorod. In such a heterostructure, the background PL from the uncoupled WS2 can be suppressed, which allows us to characterize the resonance coupling effect using correlated single-particle dark-field (DF) scattering and PL spectroscopies. Distinct mode splitting and anticrossing dispersion are observed in the scattering spectra, which originate from the resonance coupling between the excitons in the WS2 and plasmon resonance in the gold nanorod. In addition, a 1187-fold enhancement is obtained for the light emitted from the heterostructure relative to that of the pristine monolayer WS2. The emission spectra are broadened with mode-splitting features at room temperature, which can be further decomposed into two resonance modes using a coupled mode analysis. Moreover, two PL modes are polarized along the longitudinal axis of the gold nanorod. These findings show the potential of the designed individual gold nanorod-monolayer WS2 heterostructure as a platform for studying the resonance coupling effect between plasmon resonance and two-dimensional excitons.

Journal ArticleDOI
TL;DR: A single self-consistent dataset can be acquired, providing enhanced sensitivity, reduced vulnerability to machine or sample instabilities, and highly redundant linking that supports fully-automated peak picking and resonance assignment in proteinstructural studies.
Abstract: Thanks to magic-angle spinning (MAS) probes with frequencies of 60–100 kHz, the benefit of high-sensitivity 1H detection can now be broadly realized in biomolecular solid-state NMR for the analysis...

Journal ArticleDOI
TL;DR: In this article, a rainbow-based metamaterial, created by a graded array of resonant rods attached to an elastic beam, operates as a mechanical delay-line by slowing down surface elastic waves to take advantage of wave interaction with resonance.
Abstract: We experimentally demonstrate that a rainbow-based metamaterial, created by a graded array of resonant rods attached to an elastic beam, operates as a mechanical delay-line by slowing down surface elastic waves to take advantage of wave interaction with resonance. Experiments demonstrate that the rainbow effect reduces the amplitude of the propagating wave in the host structure. At the same time, it dramatically increases both the period of interaction between the waves and the resonators and the wavefield amplitude in the rod endowed with the harvester. Increased energy is thus fed into the resonators over time: we show the enhanced energy harvesting capabilities of this system.

Journal ArticleDOI
TL;DR: In this article, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer-printing process.
Abstract: Photoelectrochemical (PEC) water splitting has been regarded as a promising approach for clean H2 production with high purity.[1–3] However, the sluggish kinetics of the oxygen evolution reaction (OER), recognized as a restricting process for overall water splitting, and the high process cost for H2 production with sustainability increase the demands on the development of stable and economical photoanodes with efficient water oxidation performance.[4,5] To address this issue, n-type metal oxide semiconductors with lower bandgap energy such as hematite (α-Fe2O3) and bismuth vanadate (BiVO4) have been widely utilized due to their earth abundance and high stability in an aqueous electrolyte.[5–7] However, its short minority carrier diffusion length and poor electrical conductance restrict the carrier lifetime, which results in rapid recombination of photogenerated charge carriers with short-lived photogenerated holes.[7–11] N-type metal oxides such as hematite (α-Fe2O3) and bismuth vanadate (BiVO4) are promising candidate materials for efficient photoelectrochemical water splitting; however, their short minority carrier diffusion length and restricted carrier lifetime result in undesired rapid charge recombination. Herein, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern (hereafter, Au array) is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer-printing process. Through plasmon-induced resonance energy transfer, the Au array provides a strong electromagnetic field in the nearsurface area of the metal oxide film. The near-field coupling interaction and amplification of the electromagnetic field suppress the charge recombination with long-lived photogenerated holes and simultaneously enhance the light harvesting and charge transfer efficiencies. Consequently, an over 3.3-fold higher photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) is achieved for the Au array/α-Fe2O3. Furthermore, the high versatility of this transfer printing of Au arrays is demonstrated by introducing it on the molybdenum-doped BiVO4 film, resulting in 1.5-fold higher photocurrent density at 1.23 V versus RHE. The tailored metal film design can provide a potential strategy for the versatile application in various light-mediated energy conversion and optoelectronic devices.

Journal ArticleDOI
TL;DR: The temperature dependent Raman intensity of the WS2 samples cannot be solely interpreted by its resonance behavior, and it is concluded that the interface optical interference impacts the Ramanintensity more significantly than the change of refractive indices with temperature.
Abstract: Temperature dependent Raman intensity of 2D materials features very rich information about the material's electronic structure, optical properties, and nm-level interface spacing. To date, there still lacks rigorous consideration of the combined effects. This renders the Raman intensity information less valuable in material studies. In this work, the Raman intensity of four supported multilayered WS2 samples are studied from 77 K to 757 K under 532 nm laser excitation. Resonance Raman scattering is observed, and we are able to evaluate the excitonic transition energy of B exciton and its broadening parameters. However, the resonance Raman effects cannot explain the Raman intensity variation in the high temperature range (room temperature to 757 K). The thermal expansion mismatch between WS2 and Si substrate at high temperatures (room temperature to 757 K) make the optical interference effects very strong and enhances the Raman intensity significantly. This interference effect is studied in detail by rigorously calculating and considering the thermal expansion of samples, the interface spacing change, and the optical indices change with temperature. Considering all of the above factors, it is concluded that the temperature dependent Raman intensity of the WS2 samples cannot be solely interpreted by its resonance behavior. The interface optical interference impacts the Raman intensity more significantly than the change of refractive indices with temperature.

Journal ArticleDOI
TL;DR: In this article, the role of axion momentum dispersion as well as the effects of a background gravitational potential, which can detune the resonance due to gravitational redshift, was investigated.
Abstract: Axion-photon interactions can lead to an enhancement of the electromagnetic field by parametric resonance in the presence of a cold axion background, for modes with a frequency close to half the axion mass. In this paper, we study the role of the axion momentum dispersion as well as the effects of a background gravitational potential, which can detune the resonance due to gravitational redshift. We show, by analytical as well as numerical calculations, that the resonance leads to an exponential growth of the photon field only if (a) the axion momentum spread is smaller than the inverse resonance length, and (b) the gravitational detuning distance is longer than the resonance length. For realistic parameter values, both effects strongly suppress the resonance and prevent the exponential growth of the photon field. In particular, the redshift due to the gravitational potential of our galaxy prevents the resonance from developing for photons in the observable frequency range, even assuming that all the dark matter consists of a perfectly cold axion condensate. For axion clumps with masses below ∼ 10−13 Mo, the momentum spread condition is more restrictive, whereas, for more massive clumps, the redshift condition dominates.

Journal ArticleDOI
TL;DR: A tunable terahertz dielectric metasurfaces consisting of split gap bars in the unit cell is proposed and theoretically demonstrated, where the sharp high-quality Fano resonance can be achieved through excitation of quasi-bound states in the continuum (quasi-BIC) by breaking in-plane symmetry of the unitcell structure.
Abstract: In this paper, a tunable terahertz dielectric metasurfaces consisting of split gap bars in the unit cell is proposed and theoretically demonstrated, where the sharp high-quality Fano resonance can be achieved through excitation of quasi-bound states in the continuum (quasi-BIC) by breaking in-plane symmetry of the unit cell structure. With the structural asymmetry parameter decreasing and vanishing, the calculated eigenmodes spectra demonstrate the resonance changes from Fano to symmetry-protected BIC mode, and the radiative quality factors obey the inverse square law. Moreover, combining with graphene monolayer and strontium titanate materials, the quasi-BIC Fano resonance can be tuned independently, where the resonance amplitude can be tuned by adjusting the Fermi level of graphene and the resonance frequency can be tuned by controlling the temperature of strontium titanate materials. The proposed structure has numerous potential applications on tunable devices including modulators, switches, and sensors.

Journal ArticleDOI
TL;DR: Great success has been achieved in various optoelectronic devices by using organic resonance materials to function as smart host materials with high triplet energies, highly luminescent emitters with high quantum yields and narrow emission bands, efficient organic afterglow molecules, and sensitive fluorescent probes.
Abstract: Organic optoelectronic molecules with resonance effects are a striking class of functional materials that have witnessed booming progress in recent years Various resonances induced by particularly

Journal ArticleDOI
TL;DR: In this paper, the Boltzmann transport equation in a relaxation time approximation (RTA) was used to calculate the anisotropic transport coefficients' shear, bulk viscosity, and electrical conductivity for a multicomponent hadron resonance gas (HRG) model for a nonzero magnetic field.
Abstract: An intense transient magnetic field is produced in high energy heavy-ion collisions mostly due to the spectator protons inside the two colliding nuclei. The magnetic field introduces anisotropy in the medium, and hence the isotropic scalar transport coefficients become anisotropic and split into multiple components. Here, we calculate the anisotropic transport coefficients' shear, bulk viscosity, and electrical conductivity, and the thermal diffusion coefficients for a multicomponent hadron resonance gas (HRG) model for a nonzero magnetic field by using the Boltzmann transport equation in a relaxation time approximation (RTA). The anisotropic transport coefficient component along the magnetic field remains unaffected by the magnetic field, while perpendicular dissipation is governed by the interplay of the collisional relaxation time and the magnetic time scale, which is inverse of the cyclotron frequency. We calculate the anisotropic transport coefficients as a function of temperature and magnetic field using the HRG model. The neutral hadrons are unaffected by the Lorentz force and do not contribute to the anisotropic transports, we estimate within the HRG model the relative contribution of isotropic and anisotropic transports as a function of magnetic field and temperature. We also give an estimation of these anisotropic transport coefficients for the hadronic gas at finite baryon chemical potential (${\ensuremath{\mu}}_{B}$).