The discovery of topological acoustics has revolutionized fundamental concepts sound propagation, giving rise to strikingly unconventional acoustic edge modes immune scattering. Because the spinless nature sound, "spinlike" degree freedom crucial states in systems is commonly realized with circulating background flow or preset coupled resonator ring waveguides, which drastically increases engineering complexity. Here we realize pseudospin multipolar a simple flow-free symmetry-broken...

Abstract Ultrasonic imaging is crucial in the fields of biomedical engineering for its deep penetration capabilities and non-ionizing nature. However, traditional techniques heavily rely on impedance differences within objects, resulting poor contrast when acoustically transparent targets. Here, we propose a compact spatial differentiator underwater isotropic edge-enhanced imaging, which enhances without need agents or external physical fields. This design incorporates an amplitude...

We propose a coded acoustic metasurface (CAM) to generate Airy-like beams (ALBs) in air. A space-folding structure is designed act as the bit “1” unit of CAM, and an air with same size used “0”. Finite-element simulations demonstrate that ALBs generated by this simple CAM have excellent self-accelerating, self-healing, non-diffracting features. It found works well large frequency range 6–9 kHz, therefore, generates broadband ALB. Furthermore, two symmetrical CAMs are employed compose lens...

Multiplexing technology with increased information capacity plays a crucial role in the realm of acoustic communication. Different quantities sound waves, including time, frequency, amplitude, phase, and orbital angular momentum (OAM), have been independently introduced as physical multiplexing approach to allow for enhanced communication densities. An metasurface is decorated carbon nanotube patches, which when electrically pumped set rotate, functions hybrid mode-frequency-division...

Early research into acoustic metamaterials has shown the possibility of achieving subwavelength near-field imaging. However, a major restriction is that imaging objects must be placed in close vicinity devices. Here, we present an approach for subsurface far below diffraction limit. An metalens made holey-structured used to magnify evanescent waves, which can rebuild image at central plane. Without changing physical structure metalens, our proposed located certain distances from input...

The plasmon coupling in a three-layered Au/SiO2/Ag nanoshell has been investigated by means of Mie scattering theory. dipole–dipole and dipole–quadrupole Fano resonances have observed the extinction spectra nanoshells. With increase thickness middle layer, resonance shows blue shift magnitude this profile enhances while red reduces. outer shell, minimum its decreases both energy increase. All behaviors discussed with hybridization model. In addition, is found to show strong near-field...

An acoustic metasurface (AM) composed of space-coiling subunits is proposed to generate Airy-like beams (ALBs) by manipulating the transmitted phase. The self-accelerating, self-healing, and non-diffracting features ALBs are demonstrated using finite element simulations. We further employ two symmetrical AMs realize ALBs, resulting in highly efficient focusing. At working frequency, focal intensity can reach roughly 20 times that incident wave. It found focusing circumvent obstacles...

We demonstrate that higher-order topological insulators with C4 symmetry can be realized in two-dimensional elastic phononic crystals. Both one-dimensional edge states and zero-dimensional corner are visualized transform each other by tuning the crystalline a hierarchical structure. The systematic band structure calculations indicate wave energy structures localized remarkable robustness, which is very promising for new generations of integrated solid-state circuits great versatility. In...

The extinction spectra of a three-layered metal nanoshell, which consists particle with dielectric core, middle Ag (Au) layer, and an outer Au (Ag) shell, have been investigated by means the Mie theory. With decrease in shell thickness or layer thickness, wavelengths localized surface plasmon resonance (LSPR) for SiO2–Ag–Au (SiO2–Au–Ag) nanoshells show distinct redshifts full widths at half maximum (FWHMs) dipole peaks first then increase. We further influence embedding medium on LSPRs...

The far- and near-field properties of Au/Ag alloy nanoshell have been investigated by using Mie theory. With increasing Au content in shell, the dipole peak shows a redshift from that Ag to nanoshell. It is found effect variation shell thickness on for nanoshells plays dominant role leads significant modulation. We further near-infrared excitation at smaller wavelength can induce stronger with suitable geometry.

Artificial structure plates engraved with discrete Archimedean spiral slits have been well designed to achieve fractional acoustic vortices (FAVs). The phase and pressure field distributions of FAVs are investigated theoretically demonstrated numerically. It is found that the singularities relating integer parts topological charge (TC) result in dark spots upper half profile a low-intensity stripe lower profile, respectively. dynamic progress FAV also discussed detail as TC increases from 1...

An annulus acoustic metasurface (AAM) composed of composite labyrinthine structure (CLS) subunits has been well designed to generate fractional vortices (FAVs) in air. The FAVs with different topological charges (TCs) are realized by modulating the transmitted phase shifts through CLS subunits. evolution pressure field and distributions FAV is investigated numerically using finite element method demonstrated theoretically. As TC increases from 1 2, central singularity first splits into two...

Focused acoustic vortex (FAV) beams can steadily trap particles in three-dimensions. Previous FAV emitters are mainly based on the active device arrays. Here, we design a passive artificial structure engraved with two sets of discrete Archimedean spiral slits to generate water. The intensity and phase distributions FAVs investigated theoretically demonstrated using finite element method. constructive interference between transmitted vortices through inner outer parts achieves FAV. It is...

A dual-frequency optoelectronic oscillator (OEO) for high sensitivity pressure sensing is proposed and experimentally demonstrated. The oscillation frequency of the OEO determined by a dual-passband microwave photonic filter in loop, which implemented using phase shifted fiber Bragg gratings (PSFBGs) written side-hole to perform phase-modulation intensity-modulation conversion. When PSFBGs are experiencing pressure, wavelength difference between two notches slightly changed, leads large...

Plasmon–exciton–plasmon (PEP) couplings in Ag–J-aggregates–Ag (AJA) nanostructures are investigated using the finite element method. By adjusting geometry and incident angle, strong among localized surface plasmon resonances (LSPRs), exciton resonances, polaritons (SPPs) were achieved AJA nanostructure, resulting three new hybridized plexcimon modes. We carefully analyzed SPP–exciton–LSPR coupling behaviors nanostructure based on classic oscillator models obtained weighting efficiencies of...

Self-accelerating acoustic beams (SABs) are capable of transporting particles directionally and transmitting signals energy along curved paths. However, the majority prior SABs have only been able to deflect within a two-dimensional plane, with lateral acceleration impacted by operating frequency transverse plane size sound source. Here, we committed using designed artificial structure plates achieve self-accelerating three-dimensional (3D) helical trajectories, also known as radial beams....

Dynamic acoustic beam manipulation via tunable metasurfaces (AMs) has attracted significant attention. However, most current AMs are primarily designed for airborne sound, feature complex structural components, and serve a singular purpose. This study proposes coding Moiré metasurface (CMM) consisting of two cascaded (ACMs) to dynamically manipulate ultrasonic beams in water. The CMM merges the characteristics can achieve different manipulations by rotating ACM changing sequence. is...

Abstract Radially self-accelerating acoustic beams (RSABs) with rotating field distributions enable three-dimensional manipulation of particles. Nevertheless, the generation desired RSABs is always a challenge. In this study, we derive general form for field. We investigate correlation between intensity and phase distribution RSAB in-depth via theoretical calculations. Artificial structure plates carved Archimedean spiral slits are designed to produce two-component (TRSABs). It found that...