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摘要

通过氢化物气相外延(HVPE)方式在蓝宝石衬底上获得了GaN微米碟,其几何形态为规则的正六边形且表面平整,直径约为27 μm,高度为15 μm。光致发光(PL)实验结果表明,微米碟垂直方向和水平方向的光学谐振模式存在差异,其中水平方向支持回音壁模式(WGM)振荡。在室温条件下采用高能脉冲激光照射微米碟,当激励光功率超过7.8 μW时,PL光谱在波长374 nm附近获得多模式激光信号,其中WGM激光占优势,品质因子可达3742。最后采用COMSOL仿真软件对谐振腔进行光场模拟,并分析了其光学模式特性。

PDF全文HTML全文 光学学报 | 2020,40(12):1223001
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基于电磁感应透明原理理论研究了金刚石锡空位色心系统的光学双稳特性。研究表明,通过改变系统的参数,即探测场失谐量、耦合场失谐量和强度、合作参数等,可以显著改变系统的量子相干特性,从而可以有效调控该固态系统的光学双稳的阈值。另外,适当地调节耦合激光场的强度,可以实现光学双稳态和多稳态的相互转化。

PDF全文HTML全文 光学学报 | 2020,40(12):1219001
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针对机械微弯长周期光纤光栅的基模HE11到高阶纤芯矢量模式(TE01、TM01和HE21)的耦合特性,分析了阶跃型和反抛物线型两种少模光纤结构下机械微弯长周期光纤光栅的光栅周期、微弯幅度和耦合系数等参数对矢量模式耦合的影响。研究结果表明,耦合系数是模式耦合过程中的关键,通过施加压力改变光纤的微弯幅度可以有效调谐光栅矢量模式的耦合强度。基于反抛物线型光纤结构的机械微弯长周期光纤光栅可以特定波长激发特定的高阶矢量模式(TE01、TM01和HE21),并且由基模向高阶模式转换的谐振波长可调谐。该机械微弯长周期光纤光栅在矢量模式复用、轨道角动量的产生和复用领域有潜在的应用价值。

PDF全文HTML全文 光学学报 | 2020,40(12):1206003
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模式匹配分析法是计算亚波长光栅衍射效应的一种高效方法。对于亚波长层叠光栅,相邻的不同介质层边界处电磁场切向分量连续,每层中电磁场的各个波导模式对该层中电磁场的贡献与相邻层中电磁场切向分量的贡献相等,相邻层间模式匹配,故可将模式匹配分析法应用于亚波长层叠光栅中。通过具体实例比较了由模式匹配分析法与严格耦合波分析法计算得到的光栅衍射效率和电磁场强度分布,对比结果表明模式匹配分析法在分析亚波长层叠介质光栅方面相较于严格耦合波分析法更为高效,在收敛性以及计算速度方面有着独特的优势,且对于深刻理解层叠光栅对电磁波的衍射效应以及结合优化方法设计新型亚波长光栅、新型超表面方面具有重要意义。

PDF全文HTML全文 光学学报 | 2020,40(12):1205001
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摘要

针对压电快速倾斜镜的反作用力对有效光学元件的复杂动态耦合干扰问题,提出了基于多体系统的刚柔耦合和基于压电耦合理论的反作用力分析方法,对压电倾斜镜的反作用力进行了分析和补偿,并获取了中心柔性铰链的热点应力。理论和实验结果表明:压电耦合求解相比于多体系统的刚柔耦合方法更能准确地反映反作用力特性,实验测得反作用力的补偿比例可以达到90.14%,与数值计算的差异为3.96个百分点。所提的反作用力分析方法和动量补偿结构可为计算和消除倾斜镜的反作用力对光学系统的耦合干扰提供借鉴。

PDF全文HTML全文 中国激光 | 2020,47(06):0601007
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摘要

为解决脉冲信号对导频产生干扰进而导致马赫-曾德尔电光调制器(MZM)工作点无法稳定的问题,提出了一种导频自适应的偏压控制技术。采用数字控制系统生成频率可变的导频,由快速傅里叶变换分析反馈信号的谐波分量,可以将MZM锁定于传输曲线的最低偏置点。通过实时监测偏置电压输出,自主改变导频频率,避免脉冲信号对导频的影响,实现了高消光比的激光脉冲调制。结果表明,激光脉冲的重复频率与导频一次谐波频率接近时,脉冲信号会影响调制器工作点的稳定,该系统可以实现导频频率在0.45~2 kHz范围内的自适应变化,满足不同重复频率的激光脉冲调制需求。脉冲峰值为10 V、占空比为10 %时,调制光脉冲的消光比可达26 dB,相较于脉冲信号对导频产生干扰时,输出脉冲消光比提高了约24 dB。

PDF全文HTML全文 中国激光 | 2020,47(06):0601001
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摘要

以半导体光放大器为非线性元件的双环耦合全光缓存器(DLOB)为基础,实现了速率为2.5 Gb/s双波长数据的并行缓存。不同波长光信号合成后的功率随机波动,导致由半导体光放大器交叉相位调制产生的相位差随机波动。在考虑吸收损耗的情况下,对常用的半导体光放大器增益特性曲线进行了修正并与实测值拟合,得到了更为准确的增益特性曲线。在此基础上进行了理论分析,提出了通过调节控制光功率到最佳点以便减小相位差波动的方法。

PDF全文光学学报 | 2008,28(05):835-839
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摘要

提出一种基于中红外中空波导光纤的呼吸气体CO2测量系统,该系统使用中心波长为2.73 μm的分布式反馈(DFB)激光器结合1 m长的中空波导光纤,采用免标定波长调制光谱技术(CF-WMS)对呼吸气体CO2进行实时测量。采用CF-WMS技术得到的CO2气体浓度与配制所得的标准气体浓度之间的线性度为0.9999,在体积分数为0%~6%的范围内,测量结果与标准气体体积分数值之间的最大绝对误差为0.01%。由CF-WMS 技术反演的CO2体积分数精度为1.01×10 -5,在最佳积分时间26.00 s时,CO2气体的探测极限为1.3×10 -6。基于CF-WMS技术与传统的标定式波长调制技术(WMS)测量CO2气体体积分数的精度和灵敏度,并将两者进行比较,结果发现CF-WMS技术相对于WMS技术,测量精度提高了一倍,CF-WMS技术测量灵敏度为WMS技术测量灵敏度的1.4倍。对呼吸气体CO2实时测量时,采用CF-WMS技术测量的背景CO2体积分数基本稳定在3.8×10 -4左右,呼吸末CO2体积分数稳定在5.7%附近。

PDF全文HTML全文 光学学报 | 2020,40(11):1130001
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摘要

提出一种高光谱成像激光雷达系统的光学结构设计,并对系统的光学辐射定标方法进行研究。利用单色仪对出射光的精细扫描,确定高光谱成像雷达每个探测通道的带宽和中心波长。根据高光谱成像激光雷达方程,在实验室定标过程中,不考虑大气对定标的影响,得到系统每一个通道的定标系数。系统定标过程中合成不确定度为0.87%,扩展不确定度(k=2)为1.73%。最后对超连续谱高重复频率激光器出射的脉冲能量进行监测,使该高光谱激光雷达在机载飞行过程中,依据探测器输出的回波信号强度信息,能够实时得到地物的反射光谱信息,进而实现高精度地形获取和地表超精细分类。

PDF全文HTML全文 光学学报 | 2020,40(11):1128001
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摘要

提出了一种利用石墨烯基光学生物传感器对特异性生物小分子实现高灵敏检测的方法,采用易于修饰的磁性纳米颗粒作为生物探针载体,通过磁场控制实现磁性颗粒在石墨烯表面的吸附,优化了石墨烯表面复杂的改性过程。利用搭建的基于功能化修饰磁性纳米颗粒的石墨烯基光学生物传感器,实现了0.01 ng·mL -1的赭曲毒素A的检测,在0.01~5 ng·mL -1微小浓度范围内具有良好的响应,且表现出较好的特异性。该方法扩展了石墨烯基的光学生物传感器的应用范围,简化了生物分子的传感过程,提高了光学生物传感器的灵敏度。

PDF全文HTML全文 光学学报 | 2020,40(11):1117001
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针对水体小角度范围内后向散射强度测量难的问题,基于沙氏成像原理设计了水体沙氏激光雷达系统。介绍了水体沙氏激光雷达系统的设计、模拟及搭建,并对去离子水、自来水及河水三种水体进行水槽实验。详细介绍了多测量介质条件下的距离校正方法。将后向散射的光束宽度和强度变化情况与分光光度计测量数据进行比较,发现激光光束的宽度及强度变化表征光束衰减情况,同时可表征不同水体的后向散射强弱规律。分光光度计数据与水体沙氏激光雷达数据结果具有较好的一致性。

PDF全文HTML全文 光学学报 | 2020,40(11):1101004
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摘要

太赫兹量子级联激光器(THz-QCL)是用于实现自混合干涉的半导体激光器。利用自混合干涉效应,实验测量了THz-QCL频谱、线宽增强因子以及反馈光耦合系数。搭建了THz-QCL自混合干涉光路,基于THz-QCL驱动电压,获得了具有高信噪比的自混合干涉信号及其随反馈光光程变化的曲线。通过对自混合干涉信号进行解析,准确获得了THz-QCL在不同工作电流和温度下的激射频谱,频谱的分辨率反比于反馈光光程的变化。基于自混合干涉信号,分析得到了THz-QCL的线宽增强因子以及反馈光耦合系数。所实现的自混合干涉测量技术有望发展为物质的太赫兹频谱识别和测量技术。

PDF全文HTML全文 光学学报 | 2020,40(11):1114003
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摘要

加速稳健特征算法在多模核磁共振成像(MRI)肿瘤图像配准中,存在特征点偏少且配准精度低等问题。使用Harris角点检测法对参考图像、浮动图像的特征点进行提取和检测,接着使用圆形64维向量法生成特征描述符并进行欧氏距离匹配,来增强特征点的提取。通过设置配准图像初始化参数,确保粒子在最优值附近搜索,利用互信息作为粒子群优化算法的测度函数,增强目标函数全局最优解,通过引入平均最值,防止算法陷入早熟现象。仿真结果表明,与现有的算法相比,所提优化算法可以使多模MRI图像特征点增多且精度更高。

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摘要

采用数字微镜器件(DMD)无掩模光刻技术,以飞秒激光为光源,结合大面积拼接的方法快速制备了具有较高分辨率和毫米尺寸的大面积微纳结构。提出以单子场投影线扫描的方式进一步改善由于光场能量分布不均匀引起的结构边缘粗糙的问题,极大地降低了线条的边缘粗糙度,有效地控制了结构的精度。本研究以半导体领域常用的正性光刻胶为主要研究对象,实现了面积为7.4 mm 2的1 μm等间距线阵列和面积为38.7 mm 2的10 μm等间距线阵列结构的快速制备。本研究为大面积微纳结构制备提供了一种新方法,所制备结构可应用于气液流动、药物输运及晶体生长等领域。

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摘要

人类社会信息技术的快速发展不仅使得信息传递更加快捷,同时也对信息数据的存储产生了巨大的需求。如何对呈指数化增加的数据进行高速可靠、低能耗、低成本的长期存储已成为信息社会继续发展亟需解决的难题。为此,介绍了以玻璃为存储介质的光存储技术的发展现状,总结了玻璃介质光存储的应用方案,并对以玻璃作为存储介质的光存储技术未来发展趋势进行了展望。

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摘要

荧光显微镜因具有对样品损伤小、可进行特异性标记、适用于活体成像等优点,一直是生物医学研究中的主要手段。但光学系统自身缺陷、生物样品光学性质的不均匀性以及样品与显微镜浸润介质界面折射率的变化等导致了像差的产生,降低了成像的对比度和分辨率。自适应光学(AO)技术通过使用主动光学元件,如可变形镜、空间光调制器等,对畸变的波前(像差)进行校正,消除动态波前误差,恢复衍射受限性能。近年来,众多学者将AO系统与荧光显微镜相结合,以修正由样品不均匀性引起的像差,进而改善成像质量。介绍了AO技术的基本原理,综述了近年来AO技术在荧光显微镜成像中的应用,并对其未来发展趋势进行了展望。

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摘要

随着深度学习的不断发展与广泛运用,基于深度学习的目标检测算法已成为新的主流。为了进一步提高卷积神经网络YOLO v3(You only look once v3)的检测精度,在原算法的网络结构上添加卷积层模块对样本进行目标背景分类,并粗略调整特征图上的锚框大小。该模块输出目标背景概率后,过滤掉背景概率值低于设定阈值的样本,从而解决原算法中存在的正负样本比例失衡的问题。使用调整过的锚框替代原算法中直接由聚类生成固定大小的锚框,该过程为边界框的预测提供更优的初始值。在VOC数据集上的实验结果表明,相较于原算法,改进的YOLO v3具有更高的检测精度。

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摘要

无参考图像质量评价是近年来的研究热点,目前常用的评价算法都是从灰度空间提取特征。为了增加颜色通道信息对图像质量的反馈,分别提取了RGB(Red,Green,Blue )、LAB(Luminosity,A,B)、HSV(Hue,Saturation,Value)颜色空间中各通道下的亮度去均值对比度归一化(MSCN)系数,并用非对称广义高斯分布模型(AGGD)拟合。对拟合得到的MSCN系数统计特征,用梯度提升回归算法训练,得到无参考图像质量评价模型,并将各颜色通道训练模型和灰度空间训练模型的预测分数与主观评分进行比较。结果表明,相比灰度空间,部分颜色通道下的无参考图像质量评价模型的单调性、主客观一致性、稳定性都有一定提升,用RGB_B通道下提取的特征训练的模型性能最好,Pearson相关系数从0.63提升到0.70。

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提出了一种基于多尺度特征融合的细粒度图像分类方法。通过运用特征金字塔结构对不同层次的特征进行尺度变换,再进行信息融合;之后筛选其中包含细节特征最多的前三个区域图,将其与图像的全局特征共同作用以判断图片所属的子类类别。在公开的细粒度数据集CUB-200-2011、Stanford Dogs上进行了实验,得到的分类精度分别为85.7%和83.5%。实验结果表明该方法对于精细化物体分类具有一定的优越性。

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光声层析成像(PAT)作为一种新兴的成像技术,以独特的免标记、高分辨率、高对比度的多尺度成像能力,在生物医学成像中备受关注,正迅速向临床试验转化。得益于超声探测技术和激光技术的快速发展,PAT系统正逐步实现实时、大视场、高分辨率、高穿透深度的组织结构和功能成像。主要综述了环形阵列式PAT系统在生物医学成像中的研究进展及其在预临床和临床实践中面对的问题。

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A plethora of physical-layer techniques aim to enhance the performance of communication systems in several ways. Spectral efficiency and security are on the top of the list of enhancements; however, both are isolated and antagonistic islands of research. Augmented communication (ACom) is introduced in this Letter as the first technique that aims to combine these two enhancements in visible light communications (VLCs). The dividends of the proposed concept are demonstrated via simulations and the performance is experimentally validated. Results show that ACom can simultaneously provide the high spectral efficiency and the resistance to eavesdropping, while introducing minimal signal-to-noise ratio penalties.

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    This publisher’s note corrects the authors’ affiliations in Photon. Res.8, 940 (2020).PRHEIZ2327-912510.1364/PRJ.389553

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      Particle nanotracking (PNT) is highly desirable in lab-on-a-chip systems for flexible and convenient multiparameter measurement. An ultrathin flat lens is the preferred imaging device in such a system, with the advantage of high focusing performance and compactness. However, PNT using ultrathin flat lenses has not been demonstrated so far because PNT requires the clear knowledge of the relationship between the object and image in the imaging system. Such a relationship still remains elusive in ultrathin flat lens-based imaging systems because they operate based on diffraction rather than refraction. In this paper, we experimentally reveal the imaging relationship of a graphene metalens using nanohole arrays with micrometer spacing. The distance relationship between the object and image as well as the magnification ratio is acquired with nanometer accuracy. The measured imaging relationship agrees well with the theoretical prediction and is expected to be applicable to other ultrathin flat lenses based on the diffraction principle. By analyzing the high-resolution images from the graphene metalens using the imaging relationship, 3D trajectories of particles with high position accuracy in PNT have been achieved. The revealed imaging relationship for metalenses is essential in designing different types of integrated optical systems, including digital cameras, microfluidic devices, virtual reality devices, telescopes, and eyeglasses, and thus will find broad applications.

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        Smith–Purcell radiation (SPR) is the electromagnetic wave generated by free electrons passing above a diffraction grating, and it has played an important role in free-electron light sources and particle accelerators. Orbital angular momentum (OAM) is a new degree of freedom that can significantly promote the capacity of information carried by an electro-magnetic beam. In this paper, we propose an integrable method for generating vortex Smith–Purcell radiation (VSPR), namely, SPR carrying OAM, by having free-electron bunches pass on planar holographic gratings. VSPRs generated by different electron energies, with different topological charges of the OAM, radiation angles, and frequencies are demonstrated numerically. It is also found that, for high-order radiation, the topological charge of the OAM wave will be multiplied by the radiation order. This work introduces a new way to generate SPR with OAM and provides a method to achieve an integratable and tunable free-electron OAM wave source at different frequency.

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          摘要

          Self-powered and flexible ultrabroadband photodetectors (PDs) are desirable in a wide range of applications. The current PDs based on photothermoelectric (PTE) effect have realized broadband photodetection. However, most of them express low photoresponse and lack of flexibility. In this work, high-performance, self-powered, and flexible PTE PDs based on laser-scribed reduced graphene oxide (LSG)/CsPbBr3 are developed. The comparison experiment with LSG PD and fundamental electric properties show that the LSG/CsPbBr3 device exhibits enhanced ultrabroadband photodetection performance covering ultraviolet to terahertz range with high photoresponsivity of 100 mA/W for 405 nm and 10 mA/W for 118 μm at zero bias voltage, respectively. A response time of 18 ms and flexible experiment are also acquired at room temperature. Moreover, PTE effect is fully discussed in the LSG/CsPbBr3 device. This work demonstrates that LSG/CsPbBr3 is a promising candidate for construction of high-performance, flexible, and self-powered ultrabroadband PDs at room temperature.

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            摘要

            Nonlinear optical processes in waveguides play important roles in compact integrated photonics, while efficient coupling and manipulations inside the waveguides still remain challenging. In this work, we propose a new scheme for second-harmonic generation as well as beam shaping in lithium niobate slab waveguides with the assistance of well-designed grating metasurfaces at λ=1064 nm. By encoding the amplitude and phase into the holographic gratings, we further demonstrate strong functionalities of nonlinear beam shaping by the metasurface design, including dual focusing and Airy beam generation. Our approach would inspire new designs in the miniaturization and integration of compact multifunctional nonlinear light sources on chip.

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              摘要

              The nitrogen-vacancy (N-V) center in diamond is a widely used platform for quantum information processing and sensing. The electron-spin state of the N-V center could be initialized, read out optically, and manipulated by resonate microwave fields. In this work, we analyze the dependence of electron-spin initialization on widths of laser pulses. We build a numerical model to simulate this process and to verify the simulation results in experiments. Both simulations and experiments reveal that shorter laser pulses are helpful to the electron-spin polarization. We therefore propose to use extremely short laser pulses for electron-spin initialization. In this new scheme, the spin-state contrast could be improved about 10% in experiments by using laser pulses as short as 4 ns in width. Furthermore, we provide a mechanism to explain this effect, which is due to the occupation time in the meta-stable spin-singlet states of the N-V center. Our new scheme is applicable in a broad range of N-V-based applications in the future.

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                摘要

                The evolutions of polarization and orbital angular momentum (OAM) states of light in helically twisted birefringent photonic crystal fibers (TB-PCFs) are analyzed. It is shown that a circular polarization (CP) component (S3 of a Stokes parameter) is periodically excited when usual linearly polarized (LP) modes of PCF are launched. The excitation originates from a geometric phase in TB-PCFs. The S3 excitation is larger for larger linear birefringence for a fixed twisting rate. If the linear birefringence is large enough, a CP filtering behavior can be seen in addition to the S3 excitation. From the analytical consideration of the sign of the geometric phase, the TB-PCF with periodical inversion of twisting is proposed to generate arbitrary polarization state on the Poincaré sphere. Next, an OAM state generation in multimode TB-PCFs is shown for higher-order LP mode input. By observing a far-field interference pattern from TB-PCF mixed with LP01 mode, a vortex associated with the OAM state can be seen. Similar to the single-mode case, by using periodical twisting inversion, efficient OAM generation is possible. These results indicate that by simply launching fiber’s LP mode into TB-PCF, arbitrary polarization and OAM states can be generated, leading to a novel mechanism for the manipulation of the spatial state of light.

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                  摘要

                  We propose a linear mapping relationship between the polarization of the fundamental mode and the cylindrical vector (CV) modes on the first-order Poincaré sphere (FOPS) in fiber. The new method is based on the four-dimensional complex Jones matrices in terms of the linearly polarized mode bases. With our theoretical model, an all-fiber approach to generate arbitrary CV beams on the FOPS is proposed theoretically and verified experimentally. In the experiment, through the combination of a mode converter and a two-segment cascaded few-mode fiber with fixed stresses, it is possible to generate all CV modes on the FOPS by only adjusting the polarization of the fundamental mode. The Stokes parameters of the output light are measured to verify our scheme, which shows good agreement with the theoretical prediction. The method may provide a convenient way to generate CV beams and evolve the polarization states in any path on the FOPS, which is expected to have potential applications in encoding information and quantum computation.

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                    摘要

                    Light has been clinically utilized as a stimulation in medical treatment, such as Low-level laser therapy and photodynamic therapy, which has been more and more widely accepted in public. The penetration depth of the treatment light is important for precision treatment and safety control. The issue of light penetration has been highlighted in biomedical optics field for decades. However, quantitative research is sparse and even there are conflicts of view on the capability of near-infrared light penetration into brain tissue. This study attempts to quantitatively revisit this issue by innovative high-realistic 3D Monte Carlo modeling of stimulated light penetration within high-precision Visible Chinese human head. The properties of light, such as its wavelength, illumination profile and size are concern in this study. We made straightforward and quantitative comparisons among the effects by the light properties (i.e., wavelengths: 660, 810 and 980 nm; beam types: Gaussian and flat beam; beam diameters: 0, 2, 4 and 6 cm) which are in the range of light treatment. The findings include about 3% of light dosage within brain tissue; the combination of Gaussian beam and 810 nm light make the maximum light penetration (> 5 cm), which allows light to cross through gray matter into white mater. This study offered us, the first time as we know, quantitative guide for light stimulation parameter optimization in medical treatment.

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                      摘要

                      Amyloidopathy is one of the most prominent hallmarks of Alzheimer's disease (AD), the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregationprone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid) protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy.

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                        摘要

                        Boron nitride (BN) films for high-frequency surface acoustic wave (SAW) devices are deposited on Ti/Al/Si(111) wafers by radio frequency (RF) magnetron sputtering. The structure of BN films is investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectra, and the surface morphology and piezoelectric properties of BN films are characterized by atomic force microscopy (AFM). The results show that when the flow ratio of nitrogen and argon is 2:18, the cubic BN (c-BN) film is deposited with high purity and c-axis orientation, and when the flow ratio of nitrogen and argon is 4:20, the hexagonal BN (h-BN) film is deposited with high c-axis orientation. Both particles are uniform and compact, and the roughnesses are 1.5 nm and 2.29 nm, respectively. The h-BN films have better piezoelectric response and distribution than the c-BN films.

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                          A high-efficiency capillary-fiber optic probe is developed for measuring the concentration of trace elements. The optimal probe consists of an excitation fiber (incident fiber) and a ring of collection fibers which is made up of 6 fibers. Both simulation and experiment results show that the structure gives the higher coupling efficiency with a reasonable capillary diameter. The coupling efficiency of the probe is determined by the number and arrangement of the fibers, internal diameter and length of the fiber optic sensing probe, and the end reflectivity of the capillary. The concentration of the carbonic anhydrase solution and dezincification reagents also affect the efficiency. A fluorescence efficiency of 2.4% is obtained in zinc detection experiment.Central Universities (No.2010-Ia-020), and the Self-Determined and Innovative Research Funds of WUT (No.2012-Va-104).

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                            The steady and dynamic properties are comparatively investigated for the n-doped and non-doped InGaN LEDs. Thesimulated results show that the n-doped LED exhibits the superior luminescence and modulation performance, whichis mainly attributed to the higher carrier radiative rate of n-doped LED. The results can explain the reportedexperimental results perfectly.

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                              In this paper, a new method for the rapid, economical and convenient detection of cyclic adenosine monophosphate (cAMP) in jujube is proposed and verified. Based on near-infrared (NIR) fiber spectroscopy combined with stoichio-metric analysis, the cAMP content in red jujube can be quickly detected. 68 red jujube samples were used for the NIR spectroscopy data acquisition and the corresponding chemical values were determined. The sample set was adjusted based on the joint XY distance (SPXY) to select the correction sample set. After different preprocessing on the spectra, the partial least squares (PLS) method was used to establish the model, and the smoothed and normalized PLS model result was obtained better. The model's correction correlation coefficient (Rc), correction set mean square error (RMSEC), prediction correlation coefficient (Rp), and prediction and mean square error (RMSEP) are 0.951 5, 25.793 7, 0.910 8 and 28.228 0, respectively. The results show that NIR combined with specific chemometric methods can achieve rapid de-tection of cAMP in red jujube.

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                                摘要

                                Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS) gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful research platform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantum electrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO2 laser system are employed. All the trigger signals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure the temporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to align the electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, the photon-nuclear physics, nuclear astrophysics and some basic QED phenomena.

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                                  摘要

                                  ELI-Beamlines (ELI-BL), one of the three pillars of the Extreme Light Infrastructure endeavour, will be in a unique position to perform research in high-energy-density-physics (HEDP), plasma physics and ultra-high intensity (UHI) (>1022W=cm2) laser-plasma interaction. Recently the need for HED laboratory physics was identified and the P3 (plasma physics platform) installation under construction in ELI-BL will be an answer. The ELI-BL 10 PW laser makes possible fundamental research topics from high-field physics to new extreme states of matter such as radiation-dominated ones, high-pressure quantum ones, warm dense matter (WDM) and ultra-relativistic plasmas. HEDP is of fundamental importance for research in the field of laboratory astrophysics and inertial confinement fusion (ICF). Reaching such extreme states of matter now and in the future will depend on the use of plasma optics for amplifying and focusing laser pulses. This article will present the relevant technological infrastructure being built in ELI-BL for HEDP and UHI, and gives a brief overview of some research under way in the field of UHI, laboratory astrophysics, ICF, WDM, and plasma optics.

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                                    This paper generally compares the essential features between tokamaks and stellarators, based on previous review work individually made by authors on several specific topics, such as theories, bulk plasma transport and edge divertor physics, along with some recent results. It aims at summarizing the main results and conclusions with regard to the advantages and disadvantages in these two types of magnetic fusion devices. The comparison includes basic magnetic configurations, magnetohydrodynamic (MHD) instabilities, operational limits and disruptions, neoclassical and turbulent transport, confinement scaling and isotopic effects, plasma rotation, and edge and divertor physics. Finally, a concept of quasi-symmetric stellarators is briefly referred along with a comparison of future application for fusion reactors.

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                                        摘要

                                        传统光栅的基础研究和应用研究进展一直备受关注。然而,高阶衍射污染使传统光栅获得的光谱纯度受到严重影响。为了抑制高阶衍射贡献,人们提出了许多单级或准单级光栅的设计方案,但它们对高阶衍射的抑制效果不可避免地受到加工精度的限制。提出了一种准周期矩形孔阵列光栅,通过优化矩形孔的概率密度分布函数,获得了比以往设计更大的加工误差宽容度。对这种光栅的衍射特性进行了分析研究。理论计算表明,即使孔径相对误差超过20%,光栅也可以完全抑制二阶、三阶和四阶衍射,五阶衍射效率与一阶衍射效率之比小于0.01%,大大降低了对加工精度的要求。

                                        PDF全文HTML全文 强激光与粒子束 | 2020,32(07):072002-72002
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                                        摘要

                                        基于太赫兹(THz)波的非电离、非侵入性、高穿透性、高分辨率和光谱指纹特征,太赫兹光谱技术在生物医学方面具有巨大潜力。基于太赫兹光谱技术,结合不同分析算法,不同研究小组实现了对生物样品的定性、定量识别。然而,生物样品通常包括水在内的不同成分,导致光谱信噪比较差,最终光谱分析结果误差大。对于此类问题,降噪算法和重构算法是一个有效解决办法。这些算法通过去除光谱数据中的无效信息或提取其中

                                        PDF全文 光学学报 | 2021,41(01):013001
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                                        光学自由曲面因具有强大的像差矫正和优化系统结构的能力,被誉为现代光学系统变革性的元件。但是,由于自由曲面面形过于复杂,给其高精度检测带来了巨大的难度和挑战,限制了其制造水平,这是制约其大规模应用的瓶颈之一。目前,光学自由曲面的检测技术主要是从非球面检测技术的基础上发展而来。本文回顾了近年来光学自由曲面检测方法的发展历程,着重分析了几种典型的检测方法及其特点,并展望了自由曲面检测

                                        PDF全文 光学学报 | 2021,41(01):011201
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                                        空间激光通信技术长期以来都是通信和载荷技术领域的研究热点,具有大带宽、高速率等特点。高轨中继卫星是星间数据传输的骨干节点,随着激光通信技术成熟,激光通信链路已成为国内外高轨中继卫星数据传输的可靠技术手段。本文对国内外高轨卫星激光中继链路最新发展动态及其未来发展规划进行综述,为我国建设空间激光信息网络提供参考。

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                                        摘要

                                        随着科学技术的发展与进步,人们对成像光学系统的要求也越来越高。传统球面以及非球面可供光学设计使用的自由度较少,且结构受限,难以实现越来越高的设计要求。自由曲面打破了旋转对称以及平移对称的几何约束,其面形更为灵活,需要使用更多的参数来进行面形描述,可以为光学设计带来更多的设计自由度,特别适用于校正非旋转对称系统的像差,同时可以减少系统中元件的数量,降低系统的体积与重量,实现传统光

                                        PDF全文 光学学报 | 2021,41(01):010801
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                                        可见光和红外图像是电力巡检机器人检测电力设备健康状态的重要方式,而图像配准可以结合两类图像的优势,为后续的状态监测提供更好的依据。针对因红外图像模糊导致的配准精度下降,本文提出基于显著性梯度的归一化互信息算法。在红外图像视觉显著性检测的基础上,强化显著性区域的边缘梯度,然后将显著性梯度信息和归一化互信息结合作为配准的测度函数。其次,为了提高图像配准算法的收敛性,提出一种适用于图

                                        PDF全文 光学学报 | 2020,40(16):161003
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                                        针对先进驾驶辅助系统对车辆前视景深信息的需求,本文在无监督学习的框架下提出了一种基于单目视觉的场景深度估计方法。为了降低不同尺寸前视目标对景深估计结果的影响,该方法采用金字塔结构对输入图像进行预处理;在训练过程中,将深度估计问题转化为图像重建问题,利用双目图像设计了新的损失函数代替真实深度标签,解决了真实场景深度数据难以获取的问题;将中间多尺度的视差图统一至原输入图像尺寸,改善

                                        PDF全文 光学学报 | 2020,40(17):171501
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                                        摘要

                                        环境温度的变化引起光学系统产生热离焦现象,导致系统像质不稳定。现有无热化方法在深紫外波段内,由于材料的限制,使光学系统的无热化过程和结果变得十分复杂。因此,本文提出了运用拆分系统设计和单层衍射光学元件相结合的方法实现深紫外光学系统的无热化设计。该方法首先通过消热差、消色差方程组求解结果对深紫外光学系统进行拆分再组合简化了无热化设计过程,然后通过在组合系统中加入单层衍射光学元件简

                                        PDF全文 光学学报 | 2020,40(17):172201
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                                        摘要

                                        为了实现空间探测场景中对于探测光学系统灵敏度、探测时效性、孔径和总长等的需求,设计了一种大相对孔径大视场空间光学探测系统,依据探测器指标与目标特性计算并确定了系统设计参数,实现了对12.5等星的探测。系统采用非对称双高斯透镜组光学结构,工作于450nm~850nm波段,视场角2ω=20°,F数为1.05,入瞳口径150毫米。系统中一个透镜前表面采用XY多项式自由曲面进行设计,设计与分析结果表明,该系统弥散斑

                                        PDF全文 光学学报 | 2020,40(17):172202
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                                        卫星本体部件的闪光现象是卫星个体特征的体现,结合卫星运动特性以及镜反材质反射特性,从原理上研究了镜反部件指向确定方法,给出卫星本体反射率与镜反部件面积的确定方法。在此基础上,定量分析了卫星本体部件的闪光现象,提供一种多元模型用于描述卫星光学散射特性,并进行了实测数据验证。研究表明,多元法描述卫星光学散射特性较二元法更为全面,原理适用性更强,能够更具体的反应卫星个体独有的光学散射

                                        PDF全文 光学学报 | 2020,40(17):172901
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                                        数字均值滤波器在高精度测温系统中可以有效降低噪声,提高信噪比,但也会造成信号的失真,引入不确定度,而采集到的温度信号一般为离散时间序列信号,现有的滤波器评价方法很难量化这种信号带来的失真。本文为解决该问题,分析了温度缓变对象的温度变化特性,通过低噪声、高精度测量仪器采集被测物的典型温度信号序列,并由此构建数字均值滤波器的输入序列,从而得到该滤波器在当前输入信号模型下的不确定度,

                                        PDF全文 光学学报 | 2020,40(17):171201
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                                        针对复杂背景下船舶目标图像弱信号检测率低和可见光遥感相机的多光谱数据利用率低的问题,提出了一种面向蓝、绿、红和近红外四波段多光谱遥感图像船舶目标显著性检测算法。该算法利用四波段遥感图像中可见光图像的色彩信息较丰富、近红外图像具有对细节的描述能力较好的特点,首先将可见光蓝、绿、红三通道图像变换到CIELab色彩空间;然后将近红外图像进行非下采样轮廓波变换分解,对得到的高频分量进行非线性

                                        PDF全文 光学学报 | 2020,40(17):172801
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                                        面阵探测器作为多角度偏振成像仪的核心部件,用于实现多角度多光谱偏振辐射信息的光电转换。探测器装机之前需要对其光电性能进行全面的测量,为保证其应用性能,需对探测器进行精密控温,保证其工作在较低且稳定的温度以降低探测器的热噪声和暗电流。针对上述需求研制了一套高精度和高稳定度的科学级裸片探测器制冷系统。提出了一种基于低温循环机和薄膜电加热器相组合的探测器控温方法,减小测试光源及环境温

                                        PDF全文 光学学报 | 2020,40(17):170401
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                                        多普勒激光雷达在大气风场探测方面已经得到了广泛应用。光纤Mach-Zehnder干涉仪作为多普勒激光雷达的新型鉴频系统,具有体积小、轻便、稳定性高的优点。鉴于一般常用的单模光纤Mach-Zehnder干涉仪与望远镜接收系统的多模光纤直接耦合时能量耦合损耗严重,耦合效率低的缺点,提出采用多模光纤Mach-Zehnder干涉仪作为鉴频系统,提高耦合效率,实现能量及探测高度的提升。针对多模光纤Mach-Zehnder干涉仪可能产生

                                        PDF全文 光学学报 | 2020,40(17):170602
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                                        有限远零位补偿检验非球面装调环节多,影响着检验精度,因此提出前后零位补偿结合的无限远检验非球面光学系统,在待检镜球心前后各采用一个补偿透镜,使前后区间具有像差相关性。基于像差理论,对两片补偿透镜光学参数进行推导求解,分析初始参量与规化数据关系,再利用光学软件对计算结果进行缩放与优化,得到不同前零位补偿透镜放大率β2检验四种曲率半径凹抛物面镜的光学设计,给出检验达到的最大口径和相

                                        PDF全文 光学学报 | 2020,40(17):172203
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                                        采用自由曲面透镜作为分束器以生成具有给定能量比的离散光斑阵列。首先根据能量守恒,将入射光分为一系列与阵列光斑对应的子区域。对于每个子区域,采用变量可分离的光线映射法计算子区域与相应光斑之间的映射关系,最后采用最小二乘法构造遵循该映射关系的自由曲面。提供两个设计实例以检验自由曲面分束器的可行性:i)设计生成具有相同能量比例的高斯光斑阵列,ii)设计产生具有预设不均匀能量比例的矩形平顶

                                        PDF全文 光学学报 | 2020,40(17):172204
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                                        摘要 当目标发生旋转和尺度变化等的因素时,会导致跟踪算法出现目标丢失和精度大幅度下降等问题。因此解决目标在运动过程中出现的旋转以及尺度变化成为当前研究的热点。本文提出具有旋转特性的目标跟踪算法,该算法以Hamed等人提出的 BACF(Background-Aware Correlation Filters)为基准,保留BACF算法中的定位,将笛卡尔坐标系下的目标特征转换到极坐标系下,并采用傅里叶-梅林公式来计算目标旋转角度和尺度

                                        PDF全文 光学学报 | 2020,40(17):171502
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                                        传统离轴反射光学天线出瞳距较短,需要中继光学系统将出瞳成像于快反镜附近,这会导致后续光路和结构复杂化,且中继光学系统的后向散射光会对激光通信终端产生严重影响。针对上述缺陷,本文设计了长出瞳距离轴四反光学天线,通过将光学天线出瞳直接设计于快反镜上,省去了中继光学系统。首先,从同轴三反像差理论出发,推导了像差表达式和初始结构方程。然后,基于像差理论和出瞳位置要求,计算了离轴四反光学

                                        PDF全文 光学学报 | 2020,40(18):182201
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                                        太赫兹(THz)技术在诸多领域有着广阔的应用前景。THz探测器作为THz领域的核心器件仍面临着经济、实用和高效探测的挑战。我们设计实现了一种三维多孔石墨烯辅助胆甾相液晶胶囊测量高强度THz波的新型功率探测器。三维多孔石墨烯在0.5 - 1.5 THz范围内具有超过97%的高吸收率,利用温度超灵敏胆甾相液晶胶囊的热色特性,对稳态下太赫兹功率进行了可视化定量研究,THz探测强度高达2.77×〖10〗^2 mW/cm^2,最低探

                                        PDF全文 光学学报 | 2020,40(17):170402
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                                        光学载荷辐射定标结果的地基验证受地-气系统多因素综合影响且伴随着诸多不确定度,导致单场单次验证结果存在差异,且验证结果之间无法进行有效对比和综合分析,难以实现真正意义上的载荷辐射性能验证。本文综合考虑单场单次验证目标特性、大气环境等因素的影响,提出了一种以验证结果不确定度为权重的基于加权平均值综合定权方法,获取更接近真实值的关键比较参考值,实现单场单次验证结果的对比和综合分析。

                                        PDF全文 光学学报 | 2020,40(17):171202
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                                        针对清理空间非合作目标任务中如何获取目标的相对位置和姿态的难题,提出一种双目视觉位姿测量方法。首先,设计了基于双目视觉的位姿测量算法,利用弧支撑线段的方法快速检测目标表面的对接环,通过极线约束和光流法辅助跟踪的方法建立复杂场景下的对接环检测和筛选机制;利用两次遍历法快速标记连通区域,加入面积和曲率约束,提取目标表面特征较突出的规则标志点。利用三维重建后的对接环平面和标志点建立目

                                        PDF全文 光学学报 | 2020,40(17):171203
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