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Settled fast measurement of topological charge by direct extraction of plane wave from vortex beam

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Chinese Physics B 2021年第10期30卷 306-317页

作者： Xiao-Bo Yang Jin Hu School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China Institute of Information Engineering Chinese Academy of SciencesBeijing 100195China China Beijing Key Laboratory of Fractional Signals and Systems Beijing 100081China

A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different *** the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster *** features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.

关键词： vortex beam topological charge settled measurement

Properties of off-axis hollow Gaussian–Schell model vortex beam propagating in turbulent atmosphere

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Chinese Physics B 2020年第6期29卷 230-236页

作者： Yan-Song Song Ke-Yan Dong Shuai Chang Yan Dong Lei Zhang National and Local Joint Engineering Research Center of Space Optoelectronics Technology Changchun University of Science and TechnologyChangchun 130022China

The analytical expression of off-axis hollow Gaussian–Schell model vortex beam(HGSMVB)generated by anisotropic Gaussian–Schell model source is first *** evolution properties of off-axis HGSMVB propagating in turbulent atmosphere are *** results show that the off-axis HGSMVB with smaller coherence length or propagating in stronger turbulent atmosphere will evolve from dark hollow beam into Gaussian-like beam with a larger beam spot *** beams with different values of integer order N or the position for hollow and vortex factor R will have almost the same Gaussian-like spot distribution at the longer propagation distance.

关键词： vortex beam off-axis beam Gaussian-Schell model sources laser propagation intensity

High-efficiency nonlocal reflection-type vortex beam generation based on bound states in the continuum

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National Science Review 2023年第5期10卷 201-207页

作者： Tongyu Li Jiajun Wang Wenjie Zhang Xinhao Wang Wenzhe Liu Lei Shi Jian Zi State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures (Ministry of Education) and Department of PhysicsFudan University Department of Physics The Hong Kong University of Science and Technology

Momentum-space polarization vortices centered at symmetry-protected bound states in the continuum of a periodic structure,*** crystal slab,provide a novel nonlocal approach to generate vortex *** approach enjoys a great convenience of no precise alignment requirements,although the generation efficiency of the nonlocal generators requires further optimization before the practical *** this work,we propose a temporal-coupled-mode-theory-based guideline for high-efficiency nonlocal reflection-type vortex generator *** conversion efficiency of the vortex beam is found to be limited by the ratio of the radiative loss to the intrinsic absorption in practical *** increase this ratio through mode selection and structure design,the photonic crystal slabs are theoretically designed and experimentally characterized,showing a maximum on-resonance conversion efficiency of up to 86%.Combining high efficiency with simple fabrication and no re quirement for precise alignment,reflection-type photonic crystal slabs could offer a new and competitive way to generate vortex beams flexibly.

关键词： photonic crystal slab vortex beam bound states in the continuum

Frequency-doubled vortex beam emitter based on nonlinear Cherenkov radiation

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Chinese Optics Letters 2020年第7期18卷 82-86页

作者： Chen Lin Yan Chen Xiaoyang Li Lei Yang Rui Ni Gang Zhao Yong Zhang Xiaopeng Hu Shining Zhu National Laboratory of Solid State Microstructures College of Engineering and Applied Sciencesand School of PhysicsNanjing UniversityNanjing 210093China

In this work, we propose a new scheme to generate frequency-doubled vortex beams from a radially poled Li Nb O3 micro-ring resonator based on nonlinear Cherenkov radiation. The near-infrared fundamental wave is resonant in the micro-ring, while the second harmonic is emitted from the resonator along the Cherenkov phase-matching direction. The topological charge of the emitted second-harmonic vortex beam is determined by both the azimuthal order of the whispering galley modes and the number of nonlinear grating elements. The field distribution and the conversion efficiency of the emitted vortex beam are investigated.

关键词： vortex beam nonlinear Cherenkov radiation micro-ring resonator second harmonic generation lithium niobate

Highly twisted M-line of a vortex beam due to the coupling of ultrahigh-order modes

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Chinese Optics Letters 2021年第7期19卷 38-42页

作者： Cheng Yin Xuefen Kan Kun Guo Tao Wang Jiangming Xu Qingbang Han Jian Wu Zhuangqi Cao College of Internet of Things Engineering Hohai UniversityChangzhou 2130022China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Department of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China

In modern optics, particular interest is devoted to the phase singularities that yield complicated and twisted phase structures by photons carrying optical angular *** this paper, the traditional M-line method is applied to a vortex beam(VB) by a symmetric metal cladding waveguide chip, which can host numerous oscillating guided modes via free space *** ultrahigh-order modes(UOMs) result in high angular resolution due to the high finesse of the resonant *** show that the reflected pattern of a VB can be divided into a series of inner and outer rings, whilst both of them are highly distorted by the M-lines due to the UOMs’ *** the distribution of the energy flux into account, a simple ray-optics-based model is proposed to simulate the reflected pattern by calculating the local incident angle over the cross section of the *** theoretical simulations fit well with the experimental results, and the proposed scheme may enable new applications in imaging and sensing of complicated phase structures.

关键词： vortex beam M-line method planar waveguide

Micro-spot-welding of copper sheets with an IR vortex beam

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Chinese Optics Letters 2022年第4期20卷 44-48页

作者： Chenyang Wang Feng Wang Yingxiong Qin Fangwei Wang Xiao Yuan School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Engineering Jiangsu UniversityZhenjiang 212013China Lingyun Photoelectronic System Co.Ltd.Wuhan 430205China School of Optoelectronic Science and Engineering Soochow UniversitySuzhou 215006China

Copper welding with an infrared(IR)Gaussian laser beam usually shows obvious instability,spatters,and worse surface morphology due to the Gaussian distribution,temperature-dependent IR absorption,and high thermal conductivity in *** this paper,the IR quasi-continuous-wave Gaussian beam was converted into a vortex ring beam with a phase-plate and then applied to the micro-spot-welding of copper *** welding with the vortex beam demonstrated a significantly improved welding performance,smoother surface morphology,and higher welding ***,no spatters appeared in the welding process.

关键词： Gaussian beam vortex beam micro-spot-welding copper sheets IR fiber laser

Tunable Optical Rotation with an M-Type Atomic System Using vortex beam

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Journal of Applied Mathematics and Physics 2022年第4期10卷 1089-1097页

作者： Zhenzhu Li Department of Physics University of Shanghai for Science and Technology Shanghai China

We consider the optical rotation of the polarization of a linearly polarized probe field passing through an M-type atomic system by using the interaction between two vortex control fields and optical transitions. We investigate theoretically to generate the spatially dependent structured light with the atoms acting as a spatially varying circular birefringent medium. We show that the polarization and intensity distributions of the vector beam spatially vary by changing the orbital angular momentum (OAM) of the vortex control field.

关键词： Optical Rotation vortex beam Structured Light

Arbitrary topological charge vortex beams from carbon dots random lasers

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Rare Metals 2024年第8期43卷 3844-3853页

作者： Xiang-Dong Wang Xiao-Bo Mi Jiu-Ru He Feng-Ying Ma Jun-Qiao Wang Li Song Yong-Qiang Zhang Si-Yu Lu Yong-Sheng Hu School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Reliability and Intelligence of Electrical Equipment and Tianjin Key Laboratory of Electronic Materials and Devices School of Electronics and Information EngineeringHebei University of TechnologyTianjin 300401China Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou450001China

vortex beams have attracted great attention due to their promising applications in the fields of high-capacity optical communication,optical micromanipulation,and quantum information ***,we demonstrate vortex beams with flexible control of the topological charge and modes in a carbon dots random laser for the first *** beams with different types,including the Laguerre-Gaussian(LG),Bessel-Gaussian(BG),LG-superposition,and polarized vortex beams with topological charges up to 50,have been successfully ***,vortex beams can be well realized in carbon dots random lasers with different emission wavelengths covering from 465 to 612 *** work would not only enrich the types of vortex laser,especially for solution-processable lasers,but also provide a new route to realizing multicolor and wavelength-tunable vortex lasers.

关键词： Carbon dots Random lasers vortex beam Topological charge Spatial light modulator

Spin splitting of vortex beams on the surface of natural biaxial hyperbolic materials

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Chinese Physics B 2023年第12期32卷 372-381页

作者：梁红宋浩元李宇博于迪付淑芳 Department of Physics Harbin UniversityHarbin 150086China Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025China

We investigated the spin splitting of vortex beam on the surface of biaxial natural hyperbolic materials(NHMs)rotated by an angle with respect to the incident plane. An obvious asymmetry of spatial shifts produced by the left-handed circularly(LCP) component and right-handed circularly polarized(RCP) component is exhibited. We derived the analytical expression for in-and out-of-plane spatial shifts for each spin component of the vortex beam. The orientation angle of the optical axis plays a key role in the spin splitting between the two spin components, which can be reflected in the simple expressions for spatial shifts without the rotation angle. Based on an α-MoO_(3) biaxial NHM, the spatial shifts of the two spin components with the topological charge were investigated. As the topological charge increases, the spatial shifts also increase;in addition, a tiny spatial shift close to zero can be obtained if we control the incident frequency or the polarization of the reflected beams. It can also be concluded that the maximum of the spin splitting results from the LCP component at p-incidence and the RCP component at s-incidence in the RB-Ⅱ hyperbolic frequency band. The effect of the incident angle and the thickness of the α-MoO_(3) film on spin splitting is also considered. These results can be used for manipulating infrared radiation and optical detection.

关键词： spin splitting hyperbolic material vortex beam orbital angular momentum