华南理工大学物理与光电学院，广东 广州 510641
反手性拓扑光子态是具有抗背向散射及免疫缺陷特性的新型波导态，其在拓扑光子晶体的两个平行边界沿相同方向单向传输，在拓扑激光、集成光路、量子信息等领域展示出应用潜力。本文聚焦反手性拓扑光子态研究进展，从Dirac模型出发，推演经典Haldane模型、反手性Haldane模型以及异质Haldane模型，并展示不同拓扑态的传输行为。讨论手性边界态、反手性边界态以及单向体态在光子晶体中的实现，重点介绍基于反手性拓扑光子态的紧凑单向波导、拓扑环形腔、拓扑分束器等拓扑光学器件。最后针对反手性拓扑光子态研究面临的关键问题、未来发展趋势进行分析和展望。
反手性拓扑光子态 单向传输 拓扑光子晶体 拓扑器件 激光与光电子学进展
2024, 61(15): 1500001
1 国网宁夏电力有限公司 宁东供电公司，宁夏 银川 750411
2 云智慧(北京)科技有限公司，北京 100094
摘要：为解决区域变电站五防系统可信协同操作难度大的问题，提出了一种基于区块链的区域变电站智能五防控制方法。首先，通过虚拟专网建立区域变电站之间的通信信道，实现各变电站之间的安全通信；然后，采用区块链技术建立区域变电站之间各设备的五防可信认证机制，实现区域变电站的可信协同五防操作；最后，在某省区域变电站仿真环境应用该方法进行区域变电站智能五防控制。仿真结果表明：所提方法的操作指令正确执行率为99.92%，能实现区域变电站各设备之间的可信认证操作，提升区域变电站五防管理水平。
区域变电站 智能五防系统 区块链 可信认证 安全通信 regional substation, intelligent five-prevention s
1 太原理工大学 光电工程学院，山西 太原 030024
2 西安电子科技大学 光电工程学院，陕西 西安 710071
偏振成像技术作为一种新型的光学成像技术，可以实现抑制背景噪声、提高探测距离、获取目标细节特征和识别伪装目标等功能。由于成像空间维度的不同，偏振二维成像和偏振三维成像在不同领域中具有良好的应用前景。文中从偏振光的表示与传播方式入手，先后对偏振成像系统、偏振二维成像技术、偏振三维成像技术和基于超表面偏振器件的偏振探测及成像的研究展开综述。首先，根据偏振成像系统结构的不同，偏振成像系统可分为分时型、分振幅型、分孔径型和分焦平面型四种，并对以上偏振成像系统分别进行详细介绍和比较分析。其次，阐述了基于图像增强技术的偏振二维成像。图像增强技术分为偏振差分算法和图像融合两种。对于偏振三维成像，根据所处理反射光成分的不同，分为基于镜面反射光和漫反射光的偏振三维成像。综述了三维形貌重建过程中天顶角和方位角多值性问题的解决办法。为了高效准确地获取偏振信息，基于超表面结构的偏振器件成为当前研究的热点。进一步介绍了基于超表面偏振器件的偏振探测及成像技术。最后，总结全文并对偏振成像技术的发展前景进行展望。
光学成像 偏振二维成像 偏振三维成像 超表面结构 optical imaging 2D polarization imaging 3D polarization imaging metasurface 红外与激光工程
2023, 52(9): 20220808
Author Affiliations
Abstract
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The Purcell effect is commonly used to increase the spontaneous emission rate by modifying the local environment of a light emitter. Here, we propose a silicon dielectric cuboid nanoantenna for simultaneously enhancing electric dipole (ED), magnetic dipole (MD) and electric quadrupole (EQ) emission. We study the scattering cross section, polarization charge distribution, and electromagnetic field distribution for electromagnetic plane wave illuminating the silicon dielectric cuboid nanoantenna, from which we have identified simultaneous existence of ED, MD and EQ resonance modes in this nanoantenna. We have calculated the Purcell factor of ED, MD and EQ emitters with different moment orientations as a function of radiation wavelength by placing these point radiation source within the nanoantenna, respectively. We find that the resonances wavelengths of the Purcell factor spectrum are matching with the resonance modes in the nanoantenna. Moreover, the maximum Purcell factor of these ED, MD and EQ emitters is 18, 150 and 118 respectively, occurring at the resonance wavelength of 475, 750, and 562 nm, respectively, all within the visible range. The polarization charge distribution features allow us to clarify the excitation and radiation of these resonance modes as the physical origin of large Purcell factor simultaneously occurring in this silicon cuboid nanoantenna. Our theoretical results might help to deeply explore and design the dielectric nanoantenna as an ideal candidate to enhance ED, MD and EQ emission simultaneously with very small loss in the visible range, which is superior than the more popular scheme of plasmonic nanoantenna.
dielectric nanostructure spontaneous emission resonance Purcell effect Opto-Electronic Advances
2022, 5(2): 210024
1 北京应用物理与计算数学研究所，北京 100094
2 北京大学 应用物理与技术研究中心 高能量密度物理数值模拟教育部重点实验室工学院，北京 100871
3 中国工程物理研究院 激光聚变研究中心，四川 绵阳 621900
4 中国工程物理研究院 上海激光等离子体研究所，上海 201800
5 中国矿业大学（北京），北京 100083
6 中国海洋大学 数学科学学院，山东 青岛 266100
7 安徽大学 物理与材料科学学院，合肥 230039
激光聚变有望一劳永逸地解决人类的能源问题，因而受到国际社会的普遍重视，一直是国际研究的前沿热点。目前实现激光惯性约束聚变所面临的最大科学障碍（属于内禀困难）是对内爆过程中高能量密度流体力学不稳定性引起的非线性流动的有效控制，对其研究涵盖高能量密度物理、等离子体物理、流体力学、计算科学、强冲击物理和高压原子物理等多个学科，同时还要具备大规模多物理多尺度多介质流动的数值模拟能力和高功率大型激光装置等研究条件。作为新兴研究课题，高能量密度非线性流动问题充满了各种新奇的现象亟待探索。此外，流体力学不稳定性及其引起的湍流混合，还是天体物理现象（如星系碰撞与合并、恒星演化、原始恒星的形成以及超新星爆炸）中的重要过程，涉及天体物理的一些核心研究内容。本文首先综述了高能量密度非线性流动研究的现状和进展，梳理了其中的挑战和机遇。然后介绍了传统中心点火激光聚变内爆过程发生的主要流体力学不稳定性，在大量分解和综合物理研究基础上，凝练出了目前制约美国国家点火装置（NIF）内爆性能的主要流体不稳定性问题。接下来，总结了国外激光聚变流体不稳定性实验物理的研究概况。最后，展示了内爆物理团队近些年在激光聚变内爆流体不稳定性基础性问题方面的主要研究进展。该团队一直从事激光聚变内爆非线性流动研究与控制，以及聚变靶物理研究与设计，注重理论探索和实验研究相结合，近年来在内爆重要流体力学不稳定性问题的解析理论、数值模拟和激光装置实验设计与数据分析等方面取得了一系列重要成果，有力地推动了该研究方向在国内的发展。
激光聚变 惯性约束聚变 流体力学不稳定性 高能量密度物理 非线性流动 辐射流体力学 内爆物理 laser fusion inertial confinement fusion hydrodynamic instability high-energy-density physics nonlinear flow radiation hydrodynamics implosion physics 强激光与粒子束
2021, 33(1): 012001
Author Affiliations
Abstract
1 Institute of Laser and Intelligent Manufacturing Technology, South-Central University for Nationalities, Wuhan 430074, China
2 China Ship Development and Design Center, Wuhan 430064, China
3 School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510640, China.
Known as laser trapping, optical tweezers, with nanometer accuracy and pico-newton precision, plays a pivotal role in single bio-molecule measurements and controllable motions of micro-machines. In order to advance the flourishing applications for those achievements, it is necessary to make clear the three-dimensional dynamic process of micro-particles stepping into an optical field. In this paper, we utilize the ray optics method to calculate the optical force and optical torque of a micro-sphere in optical tweezers. With the influence of viscosity force and torque taken into account, we numerically solve and analyze the dynamic process of a dielectric micro-sphere in optical tweezers on the basis of Newton mechanical equations under various conditions of initial positions and velocity vectors of the particle. The particle trajectory over time can demonstrate whether the particle can be successfully trapped into the optical tweezers center and reveal the subtle details of this trapping process. Even in a simple pair of optical tweezers, the dielectric micro-sphere exhibits abundant phases of mechanical motions including acceleration, deceleration, and turning. These studies will be of great help to understand the particle-laser trap interaction in various situations and promote exciting possibilities for exploring novel ways to control the mechanical dynamics of microscale particles.Known as laser trapping, optical tweezers, with nanometer accuracy and pico-newton precision, plays a pivotal role in single bio-molecule measurements and controllable motions of micro-machines. In order to advance the flourishing applications for those achievements, it is necessary to make clear the three-dimensional dynamic process of micro-particles stepping into an optical field. In this paper, we utilize the ray optics method to calculate the optical force and optical torque of a micro-sphere in optical tweezers. With the influence of viscosity force and torque taken into account, we numerically solve and analyze the dynamic process of a dielectric micro-sphere in optical tweezers on the basis of Newton mechanical equations under various conditions of initial positions and velocity vectors of the particle. The particle trajectory over time can demonstrate whether the particle can be successfully trapped into the optical tweezers center and reveal the subtle details of this trapping process. Even in a simple pair of optical tweezers, the dielectric micro-sphere exhibits abundant phases of mechanical motions including acceleration, deceleration, and turning. These studies will be of great help to understand the particle-laser trap interaction in various situations and promote exciting possibilities for exploring novel ways to control the mechanical dynamics of microscale particles.
optical tweezers 3D dynamic motion ray optics method Newton mechanical equations Opto-Electronic Advances
2021, 4(1): 200015
1 华南理工大学物理与光电学院, 广东 广州 510641
2 广东晶启激光科技有限公司, 广东 东莞 523808
光子晶体是由介电材料周期排列构成的人工微结构,在集成光电子学、微纳光子学等领域具有广阔的应用前景。本文对多光束全息干涉法制作复式光子晶体进行了理论和数值研究,根据多光束干涉原理给出了一种复式光子晶体的光束配置,并编写了MATLAB仿真程序,仿真结果与理论预测符合得很好。在此基础上,研究了单束、两束、三束以及四束光的不同偏振组合对复式光子晶体元胞的影响规律。研究结果表明,光束偏振组合对元胞的影响十分显著,在不同的偏振组合条件下可以获得双水滴状、双圆形等各种元胞形状;当所有光束同为线偏振时,复式光子晶体具有最佳的对比度。此外,本文还探讨了入射光初相位的变化对复式光子晶体元胞的影响。研究结果对于设计具有各种元胞形状的复式光子晶体具有指导意义,并可用于物理实验教学。
材料 光子晶体 全息干涉法 复式微结构 数值仿真 偏振组合 对比度 光学学报
2021, 41(11): 1116002
1 华南理工大学物理与光电学院, 广东 广州 510641
2 广东晶启激光科技有限公司, 广东 东莞 523808
拓扑光子态是具有单向传输特性的新型波导态,展示出抗背向散射、障碍物及缺陷免疫等独特而神奇的物理性质。拓扑光子态因其独特性在拓扑激光器、量子信息、混合集成光路、非线性光学等领域具有广泛的潜在应用。磁光光子晶体为实现拓扑光子态、探索拓扑光子态新物性提供了重要平台。本文聚焦磁光光子晶体中拓扑光子态的研究进展,首先回顾有序、无序晶格中的拓扑光子态,揭示拓扑光子态的微观物理图像。接着讨论时间和空间反演对称性双破缺体系中的拓扑光子态,简述反手性拓扑光子态的产生。然后介绍宽带拓扑光子态及拓扑慢光态研究,展示新颖的拓扑光学现象及器件设计。最后针对磁光光子晶体中拓扑光子态研究面临的关键问题、未来发展趋势进行分析和展望。
光学器件 磁光光子晶体 拓扑光子态 微观物理图像 器件设计
Author Affiliations
Abstract
1 School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510641, China
2 Guangdong Full-Spectra Laser Technology Co., Ltd., Dongguan 523808, China
3 Dongguan Sanhang Innovation Research Institute, Dongguan 523808, China
We use the nonlinear coupled-mode theory to theoretically investigate second-harmonic generation (SHG) in subwavelength x-cut and z-cut lithium niobate (LN) thin-film waveguides and derive the analytical formula to calculate SHG efficiency in x-cut and z-cut LN thin-film waveguides explicitly. Under the scheme of optimal modal phase matching (MPM), two types of LN thin films can achieve highly efficient frequency doubling of a 1064 nm laser with a comparable conversion efficiency due to very consistent modal field distribution of the fundamental wave and second-harmonic wave with efficient overlap between them. Such a robust MPM for high-efficiency SHG in both the subwavelength x-cut and z-cut LN thin-film waveguides is further confirmed in a broad wavelength range, which might facilitate design and application of micro–nano nonlinear optical devices based on the subwavelength LN thin film.
lithium niobate thin film modal phase matching nonlinear coupled-mode theory second-harmonic generation Chinese Optics Letters
2021, 19(7): 071902
