We propose a scheme for realizing nonreciprocal bipartite and tripartite entanglement in a hybrid cavity optomagnonic system. The system consists of a tunable Fabry-Perot (FP) cavity and a microwave cavity, an yttrium iron garnet slab (YIG1) and a rotating yttrium iron garnet sphere (YIG2). The magnon modes in both YIG1 and YIG2 are strongly coupled to the microwave cavity mode, and the magnon mode in YIG1 also has a three-mode resonant interaction with the optical modes in the FP cavity. The Barnett effect causes a frequency shift of the magnon mode in YIG2. By reversing the external bias magnetic field of YIG2 to control the sign of the Barnett frequency shift, one can not only switch the entanglement partner of the optical mode between the magnon and microwave modes, but also achieve perfect on-off control of bipartite optical-microwave entanglement and tripartite optical-magnon-microwave entanglement. The study presents a flexible control scheme to realize nonreciprocal bipartite and tripartite entanglement in quantum nodes that integrate diverse physical systems such as optics, magnons, and microwaves, and may have potential applications in entanglement-based quantum networks.
We investigate the differential-reflectance signature of a Fano-type plasmonic response in a reflective plasmonic grating structure. A double-layer Au diffraction grating—designed to operate in contact with ethanol under 780-nm illumination from the analyte side—is fabricated on a sapphire substrate using electron-beam lithography and vacuum deposition. Rigorous coupled-wave analysis reveals an asymmetric reflectance peak with steep angular variation, while numerical differentiation of the reflectance spectrum produces a sharp differential reflectance dip. Reflectance mapping combined with Rayleigh anomaly and propagating surface plasmon dispersion relations, along with quantitative near-field analysis, indicates that the observed response is consistent with a Fano-type plasmonic response involving localized and propagating plasmonic components. Angular reflectance measurements reproduce both the asymmetric reflectance peak and differential reflectance dip, in good agreement with the simulations. The potential sensing performance is evaluated from the simulated refractive-index sensitivity and experimentally obtained linewidth. These results demonstrate that differential reflectance provides a useful readout of a Fano-type plasmonic response in reflective plasmonic grating sensors, particularly for low-refractive-index liquids.
The structural parameters and spectral performance of the pulse compression gratings are directly related to the design and output quality of high-power laser systems. In this paper, for the gold-coated gratings applicable to the 850–970 nm wavelength range, the effects of variations in groove density, incident angle, and out-of-plane angle on their diffraction efficiency and bandwidth were calculated and analyzed. Subsequently, the variation laws of diffraction efficiency and bandwidth of the 1200 lines/mm gold-coated grating with structural parameters were simulated and analyzed, with a focus on the diffraction efficiency variation at the 850 nm short wavelength, which is more sensitive to structural parameters. For the 1200 lines/mm grating, the simulated average diffraction efficiency over the 850–970 nm wavelength range under the out-of-plane Littrow geometry (α = αL, γ = 10°) is almost equal to that under the in-plane geometry (α = αL + 12°, γ = 0°), with a difference of only 0.04
Naturally occurring phyllosilicates such as talc and kaolinite-type minerals represent intrinsic layered two-dimensional insulators with highly anisotropic electronic and optical properties. In this work, we perform a comparative first-principles study of talc and kaolinite, along with its structural polymorphs dickite and nacrite, using density functional theory within the PBE-GGA framework. Structural relaxations, electronic band structures, and frequency-dependent dielectric functions were calculated to further analyze the effect of interlayer bonding on optical response. Talc, stabilized by van der Waals interlayer interactions, exhibits pronounced optical anisotropy with sharper ultraviolet absorption features, whereas kaolinite-type minerals, characterized by interlayer hydrogen bonding, display enhanced dielectric polarization along the direction normal to the layered planes and broader absorption spectra. The results demonstrate a direct link between interlayer coupling and optical anisotropy in layered phyllosilicates, highlighting their potential as natural wide-gap dielectric materials for photonic and optoelectronic applications.
This paper investigates the nonlinear propagation dynamics of finite Airy-Gaussian (AiG) laser beams in a uniform dense collisionless plasma using the Wentzel-Kramers-Brillouin (WKB) and paraxial ray approximations. Instead of treating the coupled beam width parameter differential equations (BWPDEs) solely as evolution equations, the beam propagation is analysed within an equivalent classical dynamical framework. The beam width evolution is reformulated as a two-dimensional dynamical system governed by propagational quasi-Hamiltonian functional and an effective pseudo-potential. An energy-like propagational quasi-Hamiltonian functional is derived characterizes the nonlinear beam dynamics. The evolution of the system is further interpreted through kinetic energy-like and effective pseudo-potential terms. The analysis reveals that, the quasi-Hamiltonian functional governs the self-trapping, oscillatory self-focusing and defocusing behavior of the beam. Different propagation regimes are identified according to the evolution of the quasi-Hamiltonian functional; near-zero values correspond to self-trapping, bounded oscillations indicate stable propagation and divergent behaviour signifies beam defocusing. The condition for self-trapping, self-focusing, defocusing and beam stability are further examined through a Hessian matrix analysis. The proposed framework provides deeper physical insights into the nonlinear dynamics of finite AiG beams and extends the conventional beam width parameter approach by revealing the underlying dynamical structure of beam propagation in plasma.
