1 哈尔滨工业大学物理学院，黑龙江 哈尔滨 150001
2 天津工业大学物理科学与技术学院，天津 300387
为克服扫描计算成像系统测量和计算速度慢的缺点，综述一些快速计算成像技术，从测量和计算方面论述提高速度的方法。在基于光场调制的计算光学成像法中，介绍轴向扫描、横向扫描、多波长扫描、散射介质、多距离等调制方式。针对快速定量相位成像技术，介绍定量相位成像方法、基于Kramers-Kronig关系的快速定量相位成像方法、基于对角扩展采样的计算成像方法、基于对称照明的单帧计算成像方法。针对自动聚焦技术，介绍自动聚焦技术分类、核心算法、基于Tanimoto系数和多相梯度绝对值的自动聚焦方法、基于特征区域提取和细分搜索的快速自动聚焦方法。
计算光学成像 调制成像 定量相位成像 自动聚焦 激光与光电子学进展
2024, 61(2): 0211007
Author Affiliations
Abstract
1 Department of Physics, Harbin Institute of Technology, Harbin 150001, China
2 Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Beijing Advanced Innovation Center for Imaging Theory and Technology, Department of Physics, Capital Normal University, Beijing 100048, China
Polarization is a basic characteristic of electromagnetic waves that conveys much optical information owing to its many states. The polarization state is manipulated and controlled for optical information security, optical encryption, and optical communication. Metasurface devices provide a new way to manipulate wave-fronts of light. A single ultrathin metasurface device can generate and modulate several differently polarized light fields, and thus carries optical information in several different channels. Terahertz (THz) waves have become widely used as carrier waves for wireless communication. Compact and functional metasurface devices are in high demand for THz elements and systems. This paper proposes a tri-layer metallic THz metasurface for multi-channel polarization generation and phase modulation with a high efficiency of approximately 80%. An azimuthally polarized THz vectorial beam generator is realized and characterized for use as a THz polarization analyzer. The incident polarization angle can be observed graphically with high accuracy. Moreover, a vectorial hologram with eight channels for different linear polarization states is demonstrated experimentally. The information in different holograms can be hidden by choosing the polarization channel for detection. This work contributes to achieving multi-functional metasurface in the THz band and can benefit THz communication and optical information security.
terahertz device polarization state hologram high-efficiency device Opto-Electronic Advances
2023, 6(2): 220012
Author Affiliations
Abstract
1 Department of Physics, Harbin Institute of Technology, Harbin 150001, China
2 Department of Physics, College of Science, Yanbian University, Yanji 133002, China
3 e-mail: szhang@ybu.edu.cn
Previous works for achieving mechanical squeezing focused mainly on the sole squeezing manipulation method. Here we study how to construct strong steady-state mechanical squeezing via the joint effect between Duffing nonlinearity and parametric pump driving. We find that the 3 dB limit of strong mechanical squeezing can be easily overcome from the joint effect of two different below 3 dB squeezing components induced by Duffing nonlinearity and parametric pump driving, respectively, without the need of any extra technologies, such as quantum measurement or quantum feedback. Especially, we first demonstrate that, in the ideal mechanical bath, the joint squeezing effect just is the superposition of the two respective independent squeezing components. The mechanical squeezing constructed by the joint effect is fairly robust against the mechanical thermal noise. Moreover, different from previous mechanical squeezing detection schemes, which need to introduce an additional ancillary cavity mode, the joint mechanical squeezing effect in the present scheme can be directly measured by homodyning the output field of the cavity with an appropriate phase. The joint idea opens up a new approach to construct strong mechanical squeezing and can be generalized to realize other strong macroscopic quantum effects.
Photonics Research
2019, 7(11): 11001229
Author Affiliations
Abstract
1 School of Computer and Information, Hefei University of Technology, Hefei 230009, China
2 Department of Optoelectronics Science, Harbin Institute of Technology at Weihai, Weihai 264209, China
3 3Department of Physics, Harbin Institute of Technology, Harbin 150001, China
4 Department of Physics, Harbin Institute of Technology, Harbin 150001, China
In this paper, an ultrathin metalens has been proposed based on a holographic metasurface that consists of elongated apertures in 40 nm gold film, which exhibit intriguing properties such as on- and off-axis focusing and also can concentrate light into multiple, discrete spots for circularly polarized incident lights. First, the spatial transmission phase distributions of the designed metalens with arbitrary focusing can be obtained by computergenerated holography. Then, the discrete phase distributions can be continuously encoded by subwavelength nanoapertures with spatially varying orientations in gold film. The simulation results show that our designed metalens can work efficiently for different types of focusing. Finally, our metasurface shows superior broadband characteristics between 670 and 810 nm, and the corresponding focal lengths of the designed lenses also can be efficiently modulated with the incident lights at different wavelengths.
Metamaterials Metamaterials Optical devices Optical devices Phase modulation Phase modulation Optical resonators Optical resonators Photonics Research
2015, 3(5): 05000252
1 中国工程物理研究院激光聚变研究中心, 四川 绵阳 621900
2 哈尔滨工业大学物理系, 黑龙江 哈尔滨 150001
利用金属表面等离激元（SPP）对光波的束缚和局域增强作用，设计了一种基于金属-电介质-金属波导布拉格光栅的全光开关。根据波导的电介质材料及其结构对有效折射率的调制作用，确定了开关各结构组成部分的材料和尺寸。通过引入金属波导滤波结构对抽运光和信号光进行了有效地分离，防止了抽运光对信号光及后续光路的干扰。使用时域有限差分算法（FDTD）对开关性能进行仿真，结果表明：新设计的全光开关在抽运光的光强为50 MW/cm2 时其消光比达到7.32 dB，开关响应时间小于2 ps，结构的横向尺寸约为400 nm。
集成光学 全光开关 时域有限差分方法 金属波导 布拉格光栅
1 北京空间机电研究所, 北京 100091
2 天津津航技术物理研究所, 天津 300000
3 哈尔滨工业大学自动化测试与控制系, 黑龙江 哈尔滨 150001
4 哈尔滨工业大学物理系, 黑龙江 哈尔滨 150001
提出了在一定的条件下，周期函数经过线性正则变换，结果仍然是周期函数，即利用线性正则变换可以产生泰伯效应，并从理论上给出了证明，得出了产生泰伯效应的条件。推导了特殊形式的线性正则变换（菲涅耳衍射、分数傅里叶变换和Gyrator变换）产生泰伯效应的条件，通过数值模拟验证了Gyrator变换的自成像条件，证明了该理论的正确性，从而将泰伯效应推广到了线性正则变换域。
信号处理 线性正则变换 泰伯效应 自成像条件
Author Affiliations
Abstract
The virtual source for generation of rotational symmetric Lorentz-Gaussian (RLG) wave whose propagating dynamics present the rotational symmetry is identified. Closed-form expressions, including integral and differential representations, are derived for this kind of Lorentz-Gaussian (LG) wave, thereby yielding paraxial approximation of the RLG beam in the appropriate regime. From the spectral representation of this wave, the first three order corrections of nonparaxial approximations are determined for a corresponding paraxial RLG beam. Moreover, the relationship between the RLG beam and the Hermite-Gaussian beam is revealed.
260.2110 Electromagnetic optics 260.1960 Diffraction theory 350.5500 Propagation 010.3310 Laser beam transmission Chinese Optics Letters
2012, 10(6): 062601
1 哈尔滨工业大学物理系, 黑龙江 哈尔滨 150001
2 哈尔滨工业大学自动化测量与控制工程系, 黑龙江 哈尔滨 150001
将分数傅里叶变换引入到双重非线性相关方法中，通过对参考图像和目标图像分数傅里叶变换谱的双重非线性操作实现非线性分数相关。该方法利用非线性参数以及分数阶控制目标的形状和纹理的权重，从而实现目标相关识别的调控。该非线性分数相关系统由一个光电混合装置实现，数值仿真表明，这种光学图像识别系统的优点在于对目标的形状失真和纹理改变的分辨能力是可调节的，并且可改善相关峰的性能，具有很强的抗噪声能力。
图像处理 分数双重非线性相关 分数傅里叶变换 可调节的分辨能力
Author Affiliations
Abstract
1 Department of Physics, Harbin Institute of Technology, Harbin 150001, China
2 Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan
By means of concurrence, we investigate the dynamics of entanglement between two initially separate atoms in succession passing through a cavity and their interaction with a Fock state field. We then analyze the effects of the atomic coherence, photon number, and atomic motion on the time evolution of atom-atom entanglement. The results show that there can be entanglement between two separate atoms, and that the threshold time for the creation of the entanglement is controllable by the photon number, atomic motion, and field-mode structure.
Concurrence 纠缠 纠缠突然产生 数态 020.0020 Atomic and molecular physics 270.0270 Quantum optics Chinese Optics Letters
2010, 8(12): 1191
Author Affiliations
Abstract
Department of Physics, Harbin Institute of Technology, Harbin 150001, China
We investigate the dynamics of strongly localized solitons trapped in remote troughs of radially periodic lattices with Kerr-type self-focusing nonlinearity. The rotary motion of solitons is found to be more stable for larger nonlinear wavenumbers, lower rotating velocity, and shorter radius of the trapping troughs. When the lattice is shrunk or expanded upon propagation, the solitons can be trapped in the original trough and move outward or inward, with their rotating linear velocity inversely proportional to the radius of the trapping troughs.
孤子 光学格子 190.0190 Nonlinear optics 190.4420 Nonlinear optics, transverse effects in 190.6135 Spatial solitons Chinese Optics Letters
2010, 8(8): 791
