Author Affiliations
Abstract
1 Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
2 School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
We propose a new type of dispersion-flattened waveguide without a slot-assisted structure that can obtain an ultra-flat group velocity dispersion profile with five or six zero-dispersion wavelengths in the mid-infrared region. The dispersion profile becomes less sensitive to the waveguide dimensions due to the absence of the slot-assisted structure, making waveguide fabrication more friendly. The dispersion profile varies between and ps/(nm · km) over a 2665 nm bandwidth from 2885 nm to 5550 nm with a flatness of nm2 · km/ps. Two different combinations of materials are demonstrated for dispersion flattening of the proposed waveguide structures. We also provide design guidance for the proposed waveguide structures with other combinations of materials.
integrated optical devices waveguides dispersion Chinese Optics Letters
2023, 21(10): 101302
Author Affiliations
Abstract
1 Hefei Innovation Research Institute, School of Microelectronics, Beihang University, Hefei 230013, China
2 Fert Beijing Institute, BDBC, Beihang University, Beijing 100191, China
3 Advanced Photonics Center, Southeast University, Nanjing 210096, China
4 Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
All-optical magnetization switching with features of low-power consumption and high writing speed is a promising road map to satisfy the demand for volume data storage. To promote denser and faster magnetic recording technologies, herein, all-optical helicity-dependent switching (AO-HDS) in multi-layer magnetic recording is proposed based on the chromatic aberration of an optical lens (Thorlabs’s N-BK7 plano-convex uncoated lens). The power of the incident beams and the thickness of the multi-layer magnetic recording film are designed carefully. Besides, the uniformity of this multi-layer magnetic recording is optimized. At last, a prototype system of information multiplexing based on this multi-layer magnetic recording technology is constructed as well. Flexible and controllable magnetization reversals in different layers are also demonstrated by tuning the wavelength and helicity of working beams. We believe that such a prototype system can pave the way for increasing the storage density in an effective and low-cost mode.
all-optical magnetization switching multi-level magnetic recording focal shift chromatic aberration Chinese Optics Letters
2020, 18(10): 102501
Author Affiliations
Abstract
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
In this Letter, an effective method using a mode selective coupler (MSC), which is composed of a three-core fiber is presented to generate optical vortices (OVs). The conversions of OVs with different topological charges, 0→±1 and 0→±3, are simulated in detail. We also prove that a higher-order topological charge can be obtained simply by changing the parameters of the fiber to increase the number of modes in the fiber. The polarization of OVs can be controlled as well.
060.2310 Fiber optics 060.5060 Phase modulation 230.2285 Fiber devices and optical amplifiers 050.4865 Optical vortices Chinese Optics Letters
2017, 15(3): 030008
中国科学技术大学光学与光学工程系, 安徽 合肥 230026
为了消除多级像和零级光的干扰,提出了一种单透镜结构的系统,获得了单一无扰的再现像。 使用Gerchberg-Saxton(GS)算法获得菲涅尔全息图,预先叠加倾斜平面波相位至菲涅尔全息图上,使再 现像移至中央位置。用成像透镜将空间光调制器(SLM)后方的虚像成像至前方,同时在成像透镜后方放置 空间滤波器,滤去多级像和零级光。调整透镜与SLM的位置可方便调整再现像的大小和位置, 缩短了光学系统的长度。利用虚像的方法为基于液晶SLM的计算全息显示提供了新的思路。
全息 空间光调制器 GS算法 纯相位全息图 holography spatial light modulator Gerchberg-Saxton algorithm phase-only hologram
中国科学技术大学光学与光学工程系, 安徽 合肥 230026
轴对称矢量光束包含径向偏振和角向偏振,具有独特的强度和偏振分布,在表面等离子体激发、 激光光镊和高分辨成像等领域有重要应用。光纤中的二阶本征模式TM01 和TE01 分别具有径向偏振 和角向偏振性质,可用于产生轴对称偏振光束。介绍了基于少模光纤光栅(FMFBG)的全光纤轴对称偏振光束的产生方法。
波导与纤维光学 轴对称偏振光束 少模光纤光栅 光纤模式 waveguide and fiber optics cylindrical vector beam few-mode fiber Bragg grating modes in fiber
1 中国科学技术大学光学与光学工程系， 安徽 合肥 230026
2 重庆卓美华视光电有限公司， 重庆 401520
人眼是三维显示的第一接受器官，在深度视觉、空间/时间分辨、颜色/亮度响应等过程有其独特作用。针对三维显示中的立体图像质量、观看舒适度和临场感特性，对自由立体显示器中立体视疲劳、表面形变、大视场角显示质量和色带效应进行研究，从柱透镜的脉冲响应函数出发进行分析，并提出解决方法，在此基础上将多视点自由立体显示用于澄江古生物群科普宣传。同时讨论了集成成像中单元图像处理、立体深度和显示分辨率的问题，以及全息显示技术中的人眼视觉特性。
视觉光学 三维显示 自由立体显示器 人眼视觉特性 集成成像 全息显示
中国科学技术大学光学与光学工程系,安徽 合肥 230026
将信号模场和增益离子横向分布函数引入功率传输方程,采用多环法计算少模 光纤放大器中信号及ASE的传输放大。 研究增益离子分布对模式竞争和信噪比(SNR)的影响。对照模型改进前后结果,给出两种模型各自适用范围。结果表明, 信号填充因子是表征不同模式在竞争中强弱地位的有效指标。增益离子集中掺杂有利于基模的放大和高阶模的抑制; 集中均匀掺杂60%～70%较利于基模选择；随着掺杂范围趋于集中, ASE显著降低,信噪比逐渐提高。
激光技术 模式竞争 分环法 放大的自发辐射 功率填充因子 laser techniques mode competition multilayer method amplified spontaneous emission filling factor
Author Affiliations
Abstract
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
A nanosecond square pulse fiber laser based on the nonlinear amplifying loop mirror (NALM) is numerically analyzed by the nonlinear Schr¨odinger equation. The fiber cavity with a NALM has a tendency to provide pulse shaping effect with nonlinearity increasing in the NALM, and the nanosecond square pulse is generated by the pulse shaping effect. The numerical results show that the stable square pulse can be obtained when the parameters of the NALM are chosen appropriately. The generated square pulses have flat top and no internal structure.
光纤激光器 纳秒方波脉冲 非线性放大环镜 脉冲整形 140.3538 Lasers, pulsed 060.2320 Fiber optics amplifiers and oscillators 060.3510 Lasers, fiber 140.4050 Mode-locked lasers Chinese Optics Letters
2011, 9(9): 091405
中国科学技术大学光学与光学工程系,安徽省光电子科学与技术重点实验室, 安徽 合肥 230026
从光纤广义非线性薛定谔方程出发,定义了用于衡量脉冲形变大小的脉冲形变因子, 定量地分析了在传输过程中脉冲形变因子、临界长度、临界功率及初始啁啾之间的关系。结果表明:在传输过程中,当 入射脉冲的峰值功率一定时,正啁啾脉冲的形变比负啁啾脉冲和无啁啾脉冲的形变小；当脉冲的初始啁啾 一定时,脉冲传输的临界长度随着传输功率的增加而降低,且随着功率的增大,不同初始啁啾脉冲的临界长 度趋于一致；在传输距离一定时,临界功率与初始啁啾呈线性变化,且啁啾的漂移对正啁啾脉冲的临界功率 影响较大。
非线性光学 脉冲形变因子 脉冲展宽因子 啁啾高斯脉冲 nonlinear optics factor of distortion broadening factor chirped Gauss pulse
1 中国科学技术大学 光学与光学工程系，安徽 合肥 230026
2 中国科学技术大学 近代力学系，安徽 合肥 230026
建立了以线阵CCD作为探测组件的激光衍射粒径测量系统用于颗粒群直径分布的测量。在数值计算的基础上，分析了传统Chin-Shifrin积分变换粒径分布反演算法存在的两个问题：小粒径反演结果的发散和多假峰现象，并结合理论分析给出了这两种现象的物理图像。提出了修正积分变换公式以解决小粒径反演结果发散的问题并针对Chin-Shifrin变换的具体应用，通过对比散射光强角分布特征，研究了Fraunhofer衍射对Mie散射近似的有效角度范围。计算结果显示，最大近似角度是随着粒径参数上升单调下降的，但积分变换的精度是不断提高的。最后，应用改进的Chin-Shifrin反演算法处理了实验测量数据，结果表明，改进的反演算法的精度较高，适合工业领域的应用。
Fraunhofer衍射 Mie散射 反演算法 粒径分布 线阵CCD Fraunhofer diffraction Mie scattering inversion algorithm particle size distribution linear CCD
