Typical suspended one-dimensional waveguides, tapered optical fibers (TOFs), combine sub-wavelength optical confinement with mechanical flexibility, enabling applications in optomechanics, quantum optics, atomic physics and sensing. However, the intrinsic mechanical modes (IMMs) of TOF, including flexural, longitudinal, and torsional modes, remain underexplored. Through analytical formulations and simulations, we comprehensively and explicitly explore the classification of various mechanical modes of a TOF. The characteristics of various TOF IMMs are investigated in detail, including frequencies, displacements, and vibration patterns. Novel degenerate IMMs are confirmed, and these modes result from dynamic coupling between the modes in the tapered and waist regions. It is also revealed that the IMMs are strongly geometry-dependent. The frequencies scale with the length and diameter of the waist, whereas linear tapers exhibit stronger energy localization than exponential tapers. The elaborate design and engineering of TOFs allow for precise mechanical resonance tuning and seamless integration with nanophotonic systems, positioning them as a versatile platform for quantum precision metrology and advanced optomechanical technologies.

Half-Heusler alloys have emerged as promising candidates for novel spintronic applications due to their exceptional properties including the high Curie temperature (TC) above room temperature and large anomalous Hall conductivity (AHC). In this work, we systematically study the magnetic and electronic properties of PtMnBi in α-, β-, and γ-phase using first-principles calculations and Monte Carlo simulations. The three phases are found to be ferromagnetic metals. In particular, the α-phase PtMnBi shows a high TC up to 802 K and a relatively large Gilbert damping of 0.085. Additionally, the γ-phase PtMnBi possesses a non-negligible AHC, reaching 203 Ω−1·cm−1 at the Fermi level. To evaluate its potential in nanoscale devices, we further investigate the α-phase PtMnBi thin films. The Gilbert dampings of α-phase PtMnBi thin films varies with film thickness and we attribute this variation to the distinct band structures at the high-symmetry point Γ, which arise from differences in film thickness. Moreover, the 1-layer (1L) α-phase thin film retains robust ferromagnetism (TC = 688 K) and shows enhanced Gilbert damping (0.14) and AHC (1116 Ω−1·cm−1) compared to the bulk. Intriguingly, under a 2% in-plane biaxial compressive strain, the Gilbert damping of 1L α-phase PtMnBi thin film increases to 0.17 and the AHC reaches 2386 Ω−1·cm−1. The coexistence of giant Gilbert damping and large AHC makes α-phase PtMnBi a compelling platform for practical spintronic applications, and highlights the potential of half-Heusler alloys in spintronic device design.

Lacunar spinel GaV4S8 is a crucial material for spintronic applications due to its emergent rare Néel-type skyrmions and unique orbitally-driven ferroelectric polarization. Nevertheless, persistent debates surround its magnetic properties and ground state, espcially in single crystals. In this study, we systematically investigate the anisotropic magnetism and phase diagrams of single-crystal GaV4S8 by combining magnetic entropy analysis and universality scaling laws. The critical exponents for single-crystal GaV4S8 are determined to be β=0.434(5), γ=1.768(3), and δ=5.025(1) at critical temperature TC=12.9(1) K. These exponents cannot be classified into any conventional universality class, indicating the coexistence of multiple magnetic interactions within this material. Utilizing universality scaling, we construct phase diagrams of single-crystal GaV4S8 for three distinct field orientations: H//[111], H//[110], and H//[100]. For H//[111] corresponding to the easy magnetic axis, the spin dimensionality analysis indicates a short-range interaction that follows J(r)∼r−5.21(4). Moreover, the phase diagrams reveal various magnetic phases, particularly a ground state of a possible cluster spin-glass in all directions. These findings elucidate the intricate magnetic interactions in single-crystal GaV4S8, which are crucial for understanding the formation of diverse non-collinear spin-ordered phases and potential applications in this system.

We present a novel approach to control light diffraction through a single subwavelength aperture (i.e., metallic slit) by designing and exploring a resonant metagrating with compound lattice containing two metaatoms. Such resonant metagrating supports two orthogonal local eigenmodes of opposite symmetry, and a lateral offset between inner metaatoms is introduced to break the lattice symmetry to reduce the orthogonality of the two local eigenmodes. We show that the lateral offset offers additional freedom for controlling aperture diffraction, producing both extraordinarily enhanced and extremely suppressed transmissions. The mechanism is that the resonant metagrating serves as a unidirectional nanocoupler that can efficiently convert the incident light into a surface plasmon wave, whose energy direction depends on the lateral offset. Our findings provide a platform for advanced nanophotonics, including high-efficiency optical sensors and enhanced nonlinear optical devices.

Surface trapping and Auger recombination typically suppress the emission of quantum dots (QDs). Understanding how these two processes affect the emission properties of QDs is critical to optimizing their photoluminescence (PL) performance. However, isolating their respective contributions can be challenging. In this study, we investigate the respective effects of surface trapping and Auger recombination on QD emission using single QD spectroscopy. The effects of surface trapping and Auger recombination on QD emission can be distinguished by analyzing the real-time changes in the radiative and non-radiative rates of the PL trajectories of single QDs. This is because Auger recombination can alter both the radiative and non-radiative rates, while surface trapping changes only the non-radiative rate. We find that when the PL trajectory of a single QD is in a gray state due to surface trapping, it can still exhibit Auger blinking induced by charging. Surface trapping introduces non-radiative recombination pathways not only for neutral exciton states but also for trion states. This further confirms that surface trapping and Auger recombination in QDs are completely independent non-radiative pathways. The ability to distinguish the respective effects of Auger recombination and surface trapping provides valuable insights into QD emission mechanisms.

Metasurfaces operating under oblique incidence conditions have attracted considerable interest in modern photonic engineering, owing to their capability to enhance angular coverage for next-generation devices including wide-field detectors, multi-angle communication arrays, and advanced radar architectures. However, conventional metasurfaces frequently suffer from limitations in preserving functional stability at high incidence angles, where performance deterioration typically stems from reduced coupling efficiency and phase mismatch. This work proposes flexible terahertz metasurfaces with an ultra-large incident angle, addressing the limitations of conventional metasurfaces that suffer from severe performance degradation under high angles and lack mechanical adaptability. The proposed metasurfaces are designed through the synergistic integration of spoof localized surface plasmons (S-LSPs) and electromagnetically induced transparency (EIT). Experimental results demonstrate that the metasurfaces exhibit polarization-insensitive behavior while maintaining stable transmission spectra under oblique incidence up to 80°. Furthermore, bending tests confirm that the transmission spectrum of the metasurfaces remains stable even under significant mechanical deformation (with a maximum central angle of 111.7°). The proposed flexible metasurfaces provide a novel design paradigm for oblique-incident metasurfaces, holding great potential for emerging applications in conformal terahertz systems and adaptive wearable photonics.

Non-Hermitian systems have been extensively studied for their unique topological properties and dynamic behaviors. In this paper, we investigate the phenomenon of edge bursts in population dynamics with rock−paper−scissors interactions, focusing on the interplay between non-Hermitian effects and biomass dissipation dynamics. We demonstrate that edge bursts occur when the energy bands form two distinct closed loops that do not intersect the real axis. Our findings reveal that the presence of non-dissipated sites is crucial for the formation of edge bursts, as they act as reservoirs, sustaining solitons near the boundaries and facilitating biomass transport to the edges. This study provides new insights into the behavior of non-Hermitian systems with open boundaries and asymmetric interactions, contributing to a broader understanding of complex phenomena in such systems.

We theoretically study the photon blockade (PB) effect in a double-cavity optomechanical system with the two-photon driving. By analytical calculations and numerical simulations, the physical mechanisms of conventional photon blockade (CPB) and unconventional photon blockade (UPB) are discussed in detail. And then we obtain the optimal parameter conditions for PB. In our work, there exist both the CPB induced by strong nonlinear interaction and the UPB caused by quantum interference. In particular, we find that CPB and UPB can occur simultaneously under the same parameters. In addition, we also prove that the appropriate values of nonreciprocal coupling and two-photon driving are favorable to the improvement of PB. Our proposal provides an idea for simultaneously realizing CPB and UPB in the optomechanical system and offers a route for constructing high-quality single-photon sources.