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Effect of anisotropic non-Kolmogorov turbulence on the evolution behavior of Gaussian Schell-model vortex beams
摘要： The effect of anisotropic non-Kolmogorov turbulence on the evolution behavior of average intensity and coherent vortices for Gaussian Schell-model (GSM) vortex beams is investigated. Based on the extended Huygens–Fresnel principle and power spectrum of the anisotropic non-Kolmogorov turbulence, the analytical expressions for the cross-spectral density and average intensity of GSM vortex beams propagating through anisotropic non-Kolmogorov turbulence are obtained. The evolution behavior of intensity and coherent vortices for GSM vortex beams in anisotropic non-Kolmogorov turbulence has been discussed in detail by numerical simulation. The results shown that the evolution behavior of coherent vortices and intensity profile depends on the effective anisotropic factor, generalized exponent factor and structure constant of anisotropic non-Kolmogorov turbulence, as well as the beam parameters, such as beam waist, wave length and correlation length.
关键词： Gaussian Schell-model vortex beams,Anisotropic non-Kolmogorov turbulence,Evolution behavior of coherent vortices
更新于2025-09-23 15:23:52
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Even-odd effect in higher-order holographic production of electron vortex beams with nontrivial radial structures
摘要： Structured electron beams carrying orbital angular momentum are currently of considerable interest, both from a fundamental point of view and for application in electron microscopy and spectroscopy. Until recently, most studies have focused on the azimuthal structure of electron vortex beams with well-defined orbital angular momentum. To unambiguously define real electron-beam states and realize them in the laboratory, the radial structure must also be specified. Here we use a specific set of orthonormal modes of electron (vortex) beams to describe both the radial and azimuthal structures of arbitrary electron wavefronts. The specific beam states are based on truncated Bessel beams localized within the lens aperture plane of an electron microscope. We show that their Fourier transform set of beams can be realized at the focal planes of the probe-forming lens using a binary computer-generated electron hologram. Using astigmatic transformation optics, we demonstrate that the azimuthal indices of the diffracted beams scale with the order of the diffraction through phase amplification. However, their radial indices remain the same as those of the encoding beams for all the odd diffraction orders or are reduced to the zeroth order for the even-order diffracted beams. This simple even-odd rule can also be explained in terms of the phase amplification of the radial profiles. We envisage that the orthonormal cylindrical basis set of states could lead to new possibilities in phase contrast electron microscopy and spectroscopy using structured electron beams.
关键词： truncated Bessel beams,astigmatic transformation,computer-generated hologram,electron vortex beams,orbital angular momentum,phase amplification
更新于2025-09-23 15:22:29
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Electromagnetic sinc Schell-model vortex beams
摘要： We introduce a new class of electromagnetic Schell-model source in which the cross-spectral density matrix possesses a sinc correlation function and a separable phase. The far-field radiation properties for the electromagnetic sinc Schell-model vortex beams generated by such source are investigated. It is shown that the far-field distributions of all statistical characteristics of such a beam possess vortex structure, depending on the topological charge and the correlation length of the source field.
关键词： electromagnetic vortex beams,polarization,Coherence
更新于2025-09-23 15:22:29
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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || Photoinduced Liquid Crystal Domain Engineering for Optical Field Control
摘要： Liquid crystals (LCs) have attracted considerable attention due to their pronounced high optical anisotropy/transparency over a wide electromagnetic spectrum, high sensibility to various external field stimuli (such as electric/magnetic field, light irradiation, and heat) and strong capability for matter and electromagnetic field interactions. Thanks to their large birefringence and reconfigurable director (i.e. local optical axis) orientation, LCs have become one of the most attractive candidates for making optical devices requiring versatile functionalities. Particularly, liquid crystal display (LCD) holds a dominant position in the flat panel display market nowadays. Essentially, they are composed of a huge number of separate light intensity modulators in the visible range. In addition to amplitude, LCs can freely manipulate other spatial degrees of light, such as polarization and phase. Through specifical designing of the director distribution of LC domains, one could arbitrarily manipulate the optical field. Optical field control is a key requirement for optics and photonics. Structured light, also known as shaped light or tailored light, is a light beam that has customized intensity, polarization, and phase. Recently, specific beams including vortex beams, vector beams (VBs), and Airy beams have been studied intensively due to their fantastic properties and diverse applications in optical trapping, laser processing, high‐resolution imaging, etc. Generally, these beams can be directly generated from Gaussian beams by spatially manipulating the amplitude or phase of light. Such manipulations could be accomplished by lens or plates with specific curvature radius, photoresist masks, or metasurfaces with delicately designed structures. However, their optical characteristics are static once the respective device is fabricated, which severely restricts corresponding applications. Thanks to the electro‐optical tunability of LCs, structured LC domains make these devices dynamic and more efficient.
关键词： vector beams,Airy beams,photoalignment,vortex beams,optical field control,structured light,Liquid crystals
更新于2025-09-23 15:21:01
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Noncanonical perfect vortex beams enabled via nonuniformly varying phase gradient
摘要： A method is proposed for generating noncanonical perfect vortex beams (PVBs) based on a theory deduced from the definition of topological charge. Varying the phase gradient of the light field in the region of the decomposed integral provides arbitrary control over the nonuniform phase distribution in the transverse plane. To correct the distorted beam shape, the traditional “perfect” method of controlling the global amplitude distribution is modified and used to adjust the local beam diameter and produce what are known as noncanonical scalar PVBs. Moreover, noncanonical vector PVBs with tunable azimuthal polarization can be obtained by combining two orthogonal circularly polarized scalar PVBs. The results of experiments and numerical simulations show that the structure of the inhomogeneous phase and polarization can be tuned arbitrarily.
关键词： scalar PVBs,noncanonical perfect vortex beams,vector PVBs,topological charge,phase gradient
更新于2025-09-23 15:21:01
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A V-Folded Digital Laser for On-Demand Vortex Beams by Astigmatic Transformation of Hermitea??Gaussian Modes <sup>*</sup>
摘要： A V-folded digital laser using a spatial light modulator (SLM) for intra-cavity loss shaping is exploited to generate Hermite–Gaussian modes with on-demand mode order. With a ??/2 astigmatic mode converter, vortex beams carrying on-demand orbital angular momentum (OAM) with a tunable range from ?11(cid:126) to 12(cid:126) are obtained. The mode order of the HG mode, hence the OAM of the vortex beam, is digitally switched by changing the phase pattern imposed on the SLM without requiring any mechanic alignment of the cavity. This work has great potential applications in various OAM-tunable vortex beams.
关键词： spatial light modulator,vortex beams,orbital angular momentum,Hermite–Gaussian modes,digital laser
更新于2025-09-23 15:19:57
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Detection of optical vortices using cyclic, rotational and reversal shearing interferometers
摘要： In this paper, the determination of the topological charge of the vortex beams by means of shearing interferometry was achieved, for both common and non-common path shearing interferometers, using simple yet effective optical elements. The recording and analysis of interference patterns from different setups was accomplished using: cyclic, rotational and reversal shearing interferometers. The use of cyclic and rotational shearing interferometers resulted in interference patterns with two oppositely oriented forks for both setups. However, with the reversal shearing interferometer, a single forked pattern was obtained and a mathematical approximation was deduced.
关键词： Topological charge,Vortex beams,Shearing interferometry
更新于2025-09-19 17:15:36
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Probability distribution of the orbital angular momentum mode of the ultrashort Laguerre-Gaussian pulsed beam propagation in oceanic turbulence
摘要： By introducing the orbital angular momentum (OAM) eigenfunctions of the pulsed beam and two-frequency mutual coherence function in oceanic turbulence, we establish the received probability distribution of OAM modes of the ultrashort Laguerre-Gaussian pulsed beam propagating through oceanic turbulence. Our results show that the higher rate of dissipation of kinetic energy per unit mass of fluid, larger inner scale, smaller ratio of temperature and salinity contributions to the refractive index spectrum, or lower dissipation rate of the mean-squared temperature will cause the smaller pulse duration by its full-width half-maximum. The pulse duration has a weak dependence on the OAM quantum number. In addition, the smaller OAM quantum number and the larger transmission distance cause the smaller pulse delay. Our results will be useful for vortex pulsed beam in the optical ocean communication and remote sensing.
关键词： Pulse,Vortex beams,Oceanic turbulence,Orbital angular momentum,Optical communication
更新于2025-09-19 17:15:36
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Multichannel Spatially Nonhomogeneous Focused Vector Vortex Beams for Quantum Experiments
摘要： The utilization of vector vortex beams (VVBs) in quantum experiments has recently become a topic of tremendous interest. However, achieving a focused, high-resolution, transmission-type, multichannel, and nonhomogeneously polarized VVB array remains a great challenge. Here, by introducing a degree of freedom on a high-order Poincaré sphere in the form of latitude-polarization control and locally tailoring the phase and transverse polarization distributions at the subwavelength scale, a single transmission-type dielectric metalens design for producing a multichannel, spatially nonhomogeneous, focused VVB array is demonstrated. Three special kinds of lattices (triangle, square, and rhombus) are demonstrated, yielding independently controllable orbital angular momentum states and polarization states of a tightly focused field in each channel. Furthermore, by using only the proposed metalens and a polarizer, a mode-demultiplexing system is realized with a mode crosstalk as low as ?34.8 dB for all four channels. The results offer a robust technological foundation for exploiting spatial degrees of freedom of structured light in the miniaturization and integration of quantum photonics devices.
关键词： mode crosstalk,metalens,mode-demultiplexing system,vector vortex beams,latitude polarization
更新于2025-09-19 17:15:36
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Gap-Surface Plasmon Metasurfaces for Broadband Circular-to-Linear Polarization Conversion and Vector Vortex Beam Generation
摘要： The ability to control and manipulate the polarization state of light is of crucial importance in many modern optical applications ranging from quantum technologies to biomedical sciences. Here, an ultrathin quarter-wave plate (QWP) with a gap-surface plasmon metasurface is designed, fabricated, and experimentally demonstrated, allowing for broadband and efficient conversion between circular and linear polarizations with ≈85% average reflectance across a 200 nm wide bandwidth in the near-infrared range (750–950 nm). Based on the QWP design, a general method is further derived to generate vector vortex beams (VVBs) that possess spatially varied distributions of the polarization vector and carry specified orbital angular momentums by using space-variant QWP unit cells. The fabricated metasurface exhibits highly efficient VVB generation over a wavelength range from 750 to 950 nm, with average efficiencies of ≈72% and ≈68% for the right circularly polarized and left circularly polarized incident light, respectively. The developed approach allows compact, cost-effective, and high-performance polarization converters to be realized, paving the way for the ultimate miniaturization of optical devices with arbitrary control of light fields.
关键词： broadband,gap-surface plasmon metasurfaces,circular-to-linear conversion,vector vortex beams
更新于2025-09-19 17:15:36