Author Affiliations
Abstract
1 Shandong Provincial Engineering and Technical Center of Light Manipulations & Shandong Provincial Key Laboratory of Optics and Photonic Device, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
2 School of Physical Science and Technology, Soochow University, Suzhou 215006, China
We investigated the Talbot effect in an anti-parity-time (PT) symmetric synthetic photonic lattice composed of two coupled fiber loops. We calculated the band structures and found that with an increase in the gain-loss parameter, the band transitions from a real spectrum to a complex spectrum. We study the influence of phase in the Hermitian operator on the Talbot effect, and the Talbot effect disappears when the period of the input field is N > 8. Further study shows that the variation of Talbot distance can also be modulated by non-Hermitian coefficients of gain and loss. This work may find significant applications in pulse repetition-rate multiplication, temporal invisibility, and tunable intensity amplifiers.
Talbot effect synthetic dimensions anti-PT symmetry photonic lattices Chinese Optics Letters
2024, 22(3): 031901
1 山东交通学院 理学院, 山东 济南 250357
2 南京航空航天大学 物理学院, 江苏 南京 211106
基于分数Talbot效应,利用纯位相光栅设计了一种二维棋盘格状阵列照明器。利用菲涅尔衍射理论分析了平面光波照射下纯位相光栅衍射光场,得到位相调制为(0,π/2)的二阶纯位相光栅可以实现压缩比为2的棋盘格状阵列照明。利用二元光学器件制作技术,在光学玻璃基底上制作了位相光栅。在扩束激光光束照射下,在分数Talbot距离处获得了效率为83.2%的棋盘格状明暗相间光斑阵列。实验结果很好地验证了理论分析结论。研究结果对于光互连、光通信、光电混合处理领域中阵列微光束生成和应用都具有较高的理论和实用价值。
衍射 光栅 Talbot效应 Talbot阵列照明器 diffraction grating Talbot effect Talbot array illuminator
华南理工大学物理与光电学院，广东 广州 510641
基于单轴晶体光束传输理论，从理论上推导了二维正交周期结构光场沿垂直单轴晶体光轴方向传播产生泰伯效应的公式。给出了泰伯效应的产生条件和常规泰伯距离的表达式，常规泰伯距离的大小决定于单轴晶体寻常光的折射率no与非寻常光折射率ne之比和二维周期结构的x方向周期px和y方向周期py之比。模拟了二维正弦光栅和二维项链光栅的光场在单轴晶体中因各向异性衍射产生的泰伯效应。两种情况都能在更短的约化泰伯距离处产生与原光栅相同的泰伯像，在半约化泰伯距离产生与原光栅互补的像；在1/4约化泰伯距离和3/4约化泰伯距离产生的泰伯子像强度分布的周期为原光栅的1/2，相位变化的周期与原光栅相同，但是在空间上有半个周期的移动。本研究将泰伯效应拓展到各向异性介质中的传播动力学，加深了人们对周期性光场的传输理论的理解。
从理论和实验两方面研究了球面波入射二维光栅的泰伯效应。首先，分析球面波入射光栅后，菲涅耳衍射区光场的复振幅分布；其次，讨论了泰伯像及分数泰伯像的成像条件，得出成像位置及成像周期由光源至光栅的距离、光栅至观察面的距离共同决定，并且球面波入射光栅的泰伯距离等于其周期放大率与平面波入射光栅泰伯距离的乘积。实验结果与理论结果相符合，在特定位置处可观察到清晰的泰伯像及分数泰伯像。改变光源平面与光栅的距离，泰伯像按特定规律发生变化。由于光栅周期小于两倍孔径边长、球面波自身发散特性，分数泰伯像中出现像元交叠现象，按交叠程度可将交叠图像分为两种分数泰伯像，即点状离散分布及棋盘分布。本文研究可促进泰伯效应在光学测量及阵列照明等方面的应用。
衍射 二维光栅 泰伯效应 菲涅耳衍射 球面波 像元交叠 激光与光电子学进展
2021, 58(11): 1105002
Author Affiliations
Abstract
1 Laboratory of Infrared Materials and Devices, Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China
2 Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
3 Laser Physics Center, Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
4 Science Program, Texas A&M University at Qatar, Doha 23874, Qatar
The nonlinear Talbot effect is a near-field nonlinear diffraction phenomenon in which the self-imaging of periodic objects is formed by the second harmonics of the incident laser beam. We demonstrate the first, to the best of our knowledge, example of nonlinear Talbot self-healing, i.e., the capability of creating defect-free images from faulty nonlinear optical structures. In particular, we employ the tightly focused femtosecond infrared optical pulses to fabricate nonlinear photonic crystals and show that the defects in the form of the missing points of two-dimensional square and hexagonal periodic structures are restored in the second harmonic images at the first nonlinear Talbot plane. The observed nonlinear Talbot self-healing opens up new possibilities for defect-tolerant optical lithography and printing.
nonlinear Talbot effect nonlinear photonic crystal periodically poled LiNbO3 second harmonic generation self-healing Chinese Optics Letters
2021, 19(6): 060011
暨南大学光子技术研究院, 广东省光纤传感与通信技术重点实验室, 广东 广州 510632
轨道角动量 (OAM)光束具有螺旋形相位分布, 在信息光学、光捕获、光学操控等领域都有着重要的应用。本文设计了一种可以生成聚焦 OAM光束的平面型光学器件。该器件利用迂回相位的编码方式, 在平板上加载了根据分数 Talbot效应计算得到的特定相位分布。使用时域有限差分 (FDTD)分别对具有正方形和六边形周期性结构的光学器件进行仿真模拟。结果表明, 平面波经过此器件可以转化为阵列型聚焦 OAM光束。该器件加工方便, 容易拼接或复制, 集成度高, 可以用来生成高质量大面积阵列型 OAM光束。
分数 Talbot效应 轨道角动量 周期性结构 迂回相位 fractional Talbot effect orbital angular momentum periodic structure detour phase
Author Affiliations
Abstract
School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
A type of scalable self-imaging capable of variable magnification or minification of periodic objects is demonstrated in the focal plane of a lens illuminated by a point source. The theory and the experimental results show that the self-imaging phenomenon can also be realized in the focal plane of a lens regardless of whether the distances satisfy the lens formula or not. The particular property of this scalable self-imaging effect is that the images in the focal plane can be controlled with different scaling factors only when the distances between the point source and the periodic object satisfy a certain condition. This discovery should open a new field of diffraction imaging and new application opportunities in precision measurement.
Talbot effect periodic object diffraction theory lens Chinese Optics Letters
2020, 18(3): 030501
1 西南技术物理研究所, 成都 610041
2 陆军装备部航空军事代表局驻成都地区军事代表室, 成都 610036
为了满足100m~3km特长焦距参量的测试校准需求, 采用Talbot-Moiré条纹技术法, 设计了一套长焦测焦仪。针对影响仪器测量不确定度的系统参量, 分别设计了校准方法, 并对仪器测量不确定度评定结果进行了实验比对验证。结果表明, 校准后仪器测量不确定度评定为6.4%; 校准后的长焦测焦仪测量结果与刀口仪测量结果满足测量不确定度比对公式; 对比结果最大为0.64, 小于1; 长焦测焦仪测量不确定度评定合理。该研究验证了长焦测焦仪系统参量校准方法的可行性。
测量与计量 长焦距测量 Talbot效应 Moiré条纹 测量不确定度 measurement and metrology long focal length measurement Talbot effect Moiré fringe measurement uncertainty
南京理工大学 电子工程与光电技术学院, 江苏 南京 210094
随着中长焦距光学元件在光学遥感、高功率激光器和天文望远镜等系统中的广泛应用, 对这类光学元件焦距的高精度测量提出要求。在双光栅干涉焦距测量技术的基础上, 提出了一种新的改进算法。该算法通过Moiré条纹倾斜角度与待测元件焦距之间的函数关系得到焦距计算公式, 并利用入射平面波时Moiré条纹的理想状态优化了该计算公式, 解决了Moiré条纹倾角基准线的确定问题, 提高了Moiré条纹角度求解精度。采用2块周期为20 μm的朗奇光栅搭建了长焦距测量装置。实验测得的透镜焦距为36.690 m, 测量重复精度达0.382‰。
物理光学 焦距测量 双朗奇光栅 泰伯效应 physical optics focal length measurement double Ronchi grating Talbot effect
1 中国科学院国家天文台南京天文光学技术研究所, 江苏 南京 210042
2 中国科学院天文光学技术重点实验室, 江苏 南京 210042
3 中国科学院大学, 北京 100049
提出了一种基于Ronchi光栅Talbot效应的相位恢复方法。将CCD相机置于Ronchi光栅的Talbot距离处,记录Ronchi光栅的自成像强度分布。通过随机并行梯度下降(SPGD)算法优化Zernike多项式系数,恢复入射相位。数值模拟实验结果表明,所提出的方法能够快速实现高精度的相位恢复,具有收敛速度快、精度高、抗噪声等优点。
光栅 光计算 相位恢复 随机并行梯度下降(SPGD)算法 Ronchi光栅 Talbot效应 Zernike多项式
