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- periodic paperclip-shaped structure
- antenna array
- mutual coupling reduction
- Bessel Function
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- Fusion temperature and Elongation speed
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- Physics
- UIN Suska Riau
- Xi'an University of the Science and Technology
- University of Riau
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Resonance Coupling in Heterostructures Composed of Silicon Nanosphere and Monolayer WS <sub/>2</sub> : A Magnetic-Dipole-Mediated Energy Transfer Process
摘要： Light?matter resonance coupling is a long-studied topic for both fundamental research and photonic and optoelectronic applications. Here we investigated the resonance coupling between the magnetic dipole mode of a dielectric nanosphere and 2D excitons in a monolayer semiconductor. By coating an individual silicon nanosphere with a monolayer of WS2, we theoretically demonstrated that, because of the strong energy transfer between the magnetic dipole mode of the nanosphere and the A-exciton in WS2, resonance coupling evidenced by anticrossing behavior in the scattering energy diagram was observed, with a mode splitting of 43 meV. In contrast to plexcitons, which involve plasmonic nanocavities, the resonance coupling in this all-dielectric heterostructure was insensitive to the spacing between the silicon nanosphere core and the WS2 shell. Additionally, the two split modes exhibited distinct light-scattering directionality. We further experimentally demonstrated the resonance coupling effect by depositing silicon nanospheres with different diameters onto a WS2 monolayer and collecting the scattering spectra of the resulting heterostructures under ambient conditions. We further demonstrated active control of the resonance coupling by temperature scanning. Our findings highlighted the potential of our all-dielectric heterostructure as a solid platform for studying strong light?matter interactions at the nanoscale.
关键词： magnetic dipole modes,two-dimensional materials,resonance coupling,two-dimension excitons,silicon nanospheres
更新于2025-09-23 15:23:52
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A miniature multi-contrast microscope for functional imaging in freely behaving animals
摘要： Neurovascular coupling, cerebrovascular remodeling and hemodynamic changes are critical to brain function, and dysregulated in neuropathologies such as brain tumors. Interrogating these phenomena in freely behaving animals requires a portable microscope with multiple optical contrast mechanisms. Therefore, we developed a miniaturized microscope with: a fluorescence (FL) channel for imaging neural activity (e.g., GCaMP) or fluorescent cancer cells (e.g., 9L-GFP); an intrinsic optical signal (IOS) channel for imaging hemoglobin absorption (i.e., cerebral blood volume); and a laser speckle contrast (LSC) channel for imaging perfusion (i.e., cerebral blood flow). Following extensive validation, we demonstrate the microscope’s capabilities via experiments in unanesthetized murine brains that include: (i) multi-contrast imaging of neurovascular changes following auditory stimulation; (ii) wide-area tonotopic mapping; (iii) EEG-synchronized imaging during anesthesia recovery; and (iv) microvascular connectivity mapping over the life-cycle of a brain tumor. This affordable, flexible, plug-and-play microscope heralds a new era in functional imaging of freely behaving animals.
关键词： freely behaving animals,multi-contrast imaging,neurovascular coupling,miniaturized microscope,functional imaging
更新于2025-09-23 15:23:52
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heterostructures: Examination of spin relaxation mechanism
摘要： The thickness, temperature, and composition studies of spin diffusion length (SDL) and spin Hall angle (SHA) are performed by measuring the spin Hall magnetoresistance in Pd1?xPtx/Y3Fe5O12 (=YIG) heterostructures. The SDL is found to be invariant to changes in the electron momentum relaxation time by varying the temperature, the normal metal (NM) thickness, or the alloy composition, while the SHA exhibits a nonmonotonic dependence on temperature. These findings suggest the appearance of D’yakonov-Perel’ spin relaxation mechanism and phonon skew scattering in our heterostructures that is associated with strong interfacial Rashba spin-orbit coupling (IRSOC). At last, we employ the ab initio calculations to quantify the IRSOC at the inversion-symmetry-broken NM/YIG interface.
关键词： spin diffusion length,spin relaxation mechanism,spin Hall angle,interfacial Rashba spin-orbit coupling,PdPt/YIG heterostructures
更新于2025-09-23 15:23:52
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The sintering behavior and physical properties of Li <sub/>2</sub> CO <sub/>3</sub> -doped Bi <sub/>0.5</sub> (Na <sub/>0.8</sub> K <sub/>0.2</sub> ) <sub/>0.5</sub> TiO <sub/>3</sub> lead-free ceramics
摘要： In this study, Li2CO3-doped Bi0.5(Na0.8K0.2)0.5TiO3 (BNKT) ceramics were fabricated via the conventional solid-state reaction using ultrasound waves for preliminary milling. The milling time was shortened from 20 h to 1 h with ball milling. The phase structure of BNKT investigated by X-ray diffraction showed a single perovskite phase. With increasing Li2CO3 content, the phase structure of the ceramics changed from rhombohedral to tetragonal. At a sintering temperature of 1 100 8C and Li2CO3 content of 0.4 wt.%, the best physical properties of the ceramics, such as density (q), 5.9 g cm–3; electromechanical coupling factors (kp), 0.32; (kt), 0.29; remanent polarization (Pr), 12.0 lC cm–2; dielectric constant (er), 1 191; and highest dielectric constant (emax), 5 800, were obtained.
关键词： Lead-free ceramics,Electromechanical coupling factor,BNKT,Sintering temperature,Dielectric constant
更新于2025-09-23 15:23:52
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Magnetostrictive effect in micro-dotted FeCo film coated surface acoustic wave devices
摘要： The magnetostrictive effect in micro-dotted FeCo film coated surface acoustic wave (SAW) devices was demonstrated by solving coupling equations using the specific coupling of modes parameters extracted by FEM analysis. Dotted-pattern on FeCo thin-film proposed in this work contributes well to suppression in hysteresis effect by fully releasing the internal coericivity of the magnetistrictive FeCo thin-film. The theoretical demonstration was confirmed well by characterizing the constructed SAW magnetic devices with FeCo dots depositing along the SAW propagation path. Significantly improvements on suppression of hysteresis phenomenon were observed by characterizing the prepared FeCo dots coated SAW magnetic devices, higher magneto-sensitivity of 21.17 kHz mT?1, and lower hysteresis error of 0.82% were achieved successfully.
关键词： magnetostrictive effect,coupling of modes,hysteresis,micro-dotted FeCo film,SAW magnetic device
更新于2025-09-23 15:23:52
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Engineering bilinear mode coupling in circuit QED: Theory and experiment
摘要： Photonic states of high-Q superconducting microwave cavities controlled by superconducting transmon ancillas provide a platform for encoding and manipulating quantum information. A key challenge in scaling up the platform towards practical quantum computation is the requirement to communicate on demand the quantum information stored in the cavities. It has been recently demonstrated that a tunable bilinear interaction between two cavity modes can be realized by coupling the modes to a bichromatically driven superconducting transmon ancilla, which allows swapping and interfering the multiphoton states stored in the cavity modes [Gao et al., Phys. Rev. X 8, 021073 (2018)]. Here we explore both theoretically and experimentally the regime of relatively strong drives on the ancilla needed to achieve fast SWAP gates but which can also lead to undesired nonperturbative effects that lower the SWAP fidelity. We develop a theoretical formalism based on linear response theory that allows one to calculate the rate of ancilla-induced interaction, decay, and frequency shift of the cavity modes in terms of a susceptibility matrix. We go beyond the usual perturbative treatment of the drives by using Floquet theory, and find that the interference of the two drives can strongly alter the system dynamics even in the regime where the standard rotating wave approximation applies. The drive-induced ac Stark shift on the ancilla depends nontrivially on the drive and ancilla parameters which in turn modify the strength of the engineered interaction. We identify two major sources of infidelity due to ancilla decoherence. (i) Ancilla dissipation and dephasing lead to incoherent hopping among Floquet states which occurs even when the ancilla is at zero temperature; this hopping results in a sudden change of the SWAP rate, thereby decohering the SWAP operation. (ii) The cavity modes inherit finite decay from the relatively lossy ancilla through the inverse Purcell effect; the effect becomes particularly strong when the ac Stark shift pushes certain ancilla transition frequencies to the vicinity of the cavity mode frequencies. The theoretical predictions agree quantitatively with the experimental results, paving the way for using the developed theory for optimizing future experiments and architecture designs.
关键词： decoherence,transmon ancilla,superconducting cavities,ac Stark shift,quantum information,circuit QED,inverse Purcell effect,bilinear mode coupling,SWAP gates,Floquet theory
更新于2025-09-23 15:23:52
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General condition for realizing a collinear spin-orbit effective magnetic field in two-dimensional electron systems and its application to zinc-blende and wurtzite quantum wells
摘要： In this paper, we have studied two-dimensional (2D) electron systems described by the effective Hamiltonians containing spin-orbit coupling (SOC) terms up to an arbitrary odd order in wave vector k. The general condition for realizing a SOC-induced effective magnetic field (SOF) in such systems, formulated only in terms of the SOC parameters, is derived. When this condition is satisfied, the projection of the electron spin on the direction of the collinear SOF is a conserved quantity. The complete set of the k-linear and k-cubic Dresselhaus SOC contributions to the effective 2D Hamiltonian of an arbitrarily oriented zinc-blende quantum well is computed by a proper averaging of the corresponding tight-binding bulk SOC Hamiltonian. We investigate possibilities for realization of the collinear SOF in zinc-blende quantum wells of different orientation and obtain some interesting findings, which supplement the results of earlier works. Application of the developed formalism to wurtzite semiconductor 2D systems shows that the collinear SOF can be also realized in a wide class of such quantum wells.
关键词： effective magnetic field,spin-orbit coupling,quantum wells,wurtzite,zinc-blende
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Mutual Coupling Reduction Using I-Shaped Microstrip Line and X-Shaped Slot
摘要： A novel decoupling structure composed of an I-shaped microstrip line and an X-shaped slot etched from the ground plane is proposed and applied to decouple the conventional antenna array at 5.25GHz, whose typical edge-to-edge distance is 10mm (0.175λ0). Results indicate that the structure has superior decoupling capability, achieving a maximum 34.2dB reduction of mutual coupling. With wider impedance bandwidth, high isolation and improved gain, the structure is potential in the application of multi-element array and communication system.
关键词： slot,microstrip line,mutual coupling,antenna array
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Novel Frequency Reconfigurable Coupling Microstrip Patch Antenna
摘要： In this paper, a novel frequency reconfigurable coupling microstrip patch antenna is presented. A coplanar waveguide (CPW) feed line integrated on the ground plane is adopted in the structure to provide TM21 mode. Four PIN diodes are mounted on the patch gap to achieve frequency reconfiguration. By controlling the on-off state of PIN diodes electronically, resonant frequency points (5.75, 5.84, and 6.06 GHz) can be adjusted. What's more, a wide tunable range is achieved by loading more parasitic patch.
关键词： coplanar waveguide feed,coupling,Patch antenna,frequency reconfigurable
更新于2025-09-23 15:22:29
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Effective light polarization insensitive and omnidirectional properties of Si nanowire arrays developed on different crystallographic planes
摘要： In this paper, fabrication of vertical Si nanowire arrays (SiNWAs) by a facile metal assisted electroless etching approach on different crystallographic planes of Si has been reported. A very low specular reflectance (Rspec) of 0.04% and 0.03% has been achieved in the whole visible range for SiNWAs grown on Si(100) and Si(111) oriented substrates, respectively. High broadband enhancement has been detected for vertical SiNWAs due to multiple scattering paths inside the nanowire arrays. On the other hand, inclined nanowires showed a fascinating behavior at the longer wavelength regime, where light gets the longer path to reflect back-forth and ease to reflect back outward at normal incidence. Moreover, for [100] SiNWAs, transverse electric (TE) field component demonstrates the strong polarization insensitive properties at the expense of transverse magnetic (TM) field component with a minimum reflectance of < 2% up to 1200 nm. The [100] SiNWAs demonstrates extra-ordinary omnidirectional properties at θB ≥ 58o. Theoretical validation of COMSOL with an effective medium approach reveal the effective dipole coupling and the presence of strong absorption modes for vertical SiNWs at a typical wavelength regime. The highly bound states of the particle tunneling through classical forbidden region shows a strong enhancement in light absorption effect.
关键词： nanocavities,Si nanowires,light coupling effect,omnidirectional,polarization
更新于2025-09-23 15:22:29