Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
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Integrated Simulation of Opto-Mechanical System
No full text建立了光机一体化仿真方法,从而实现对光学系统的性能评估.利用Ansys有限元软件进行热-结构仿真,将得到的数据文件进行刚体位移分离时采用新的评价函数,通过设置位移参量和随机值验证计算精度达到0.3%.运用Householder算法做Zernike拟合,将拟合系数作为与ZEMAX进行通信的数据接口,并采用动态数据交换技术实现Matlab与Zemax的数据交换.在此基础上给出一个角度检测物镜仿真的实例,得到了光学畸变随温度变化的曲线,说明为达到1的测量精度,需保证工作温度范围为14~26℃.国家自然科学基金青年科学基金An integrated simulation method is established,and the performance assessment of optical systems is obtained,accordingly.New assessment functions are used for rigid-body displacement separation,which is conducted by deformation data from the Ansys thermal simulation.The computational accuracy of 0.3%is tested through setting displacement parameter and random value.Householder algorithm is adopted for Zernike fitting, and the Zernike coefficients are used as the interface for data exchange with Zemax,which is achieved by dynamic data exchange technology.The simulation of an objective lens is taken as an example,and a distortion-thermal curve is presented.The result indicates that in order to guarantee measuring accuracy of 1,the working temperature should be in the range from 14℃to 26℃
Nondestructive Analysis of Blue and White Porcelain Excavated from Nan ao No. 1 Shipwreck
No full text为揭示早期青花瓷器的综合信息并探索青花瓷分类和产地识别的科学分析方法,将X射线荧光(XRF)光谱分析技术与光学相干层析(OCT)成像相结合,对南澳一号沉船出水的不同产地明代青花瓷瓷片釉面断层结构特征、胎釉及青花钴料的化学成分特征进行了分析。结果表明,产自景德镇和漳州的明代青花瓷在上述特征方面差异明显,具有鲜明的产地特征。同时,根据白釉断层结构和瓷胎、青花成分的明显差异将漳州青花瓷分为可能出自当地不同窑口的两类。此外,利用OCT技术对景德镇青花瓷的青花图案进行了三维扫描,证实了采用OCT技术研究青花纹饰纹理国家973计划; 国家自然科学基金To reveal comprehensive information and explore scientific methods for classification and provenance recognition of ancient Chinese blue and white porcelains, X-ray fluorescence (XRF) spectroscopy combined with optical coherence tomography (OCT) is used to study the glaze cross-section structure of blue and white porcelains excavated from the Nan'ao No. 1 shipwreck in the Ming dynasty of China. The characteristics of glaze cross-section structures and chemical compositions of glaze, body and cobalt pigment are obtained. The experimental results show that the blue and white porcelain samples originated from Jingdezhen and Zhangzhou are different in terms of glaze cross-section structure and chemical composition of glaze, body and cobalt pigment. According to the obvious difference of white glaze cross-section structures and chemical compositions of body and blue pigment, the blue and white porcelain samples originated from Zhangzhou can be divided into two types made by different kilns. In addition, the blue decorative pattern of blue and white porcelain samples originated from Jingdezhen is studied by three-dimensional scanning function of OCT, which indicates that the combination of OCT and XRF is validated as an effective method to study the classification, provenance and access to comprehensive information of ancient Chinese blue and white porcelains
Effect of SiO2 on the Stark splitting enlargement of Yb3+ in phosphate glass
No full text基于传统磷酸盐玻璃组分, 通过引入SiO_2获得了改性的PS系列玻璃, 并研究了Yb~(3+)在PS系列玻璃中下能级Stark分裂及其光谱性质. 通过对该系列玻璃的吸收光谱、荧光光谱以及拉曼光谱的表征与分析确定了荧光光谱中最大波长处峰的属性. 结果表明: SiO_2的引入显著增大了Yb~(3+)下能级Stark分裂, 20 mol% SiO_2可将Stark分裂值从670 cm~(-1)提高到771 cm~(-1). 同时, 改进的磷酸盐玻璃光谱性能没有出现预期的降低现象, 反而得到了一定的改善. 实验证National Natural Science Foundation of China [61177083]Up to now, high-energy large-scale Yb3+ laser has still faced to the fact that no proper gain media are available, though researchers made a more than ten year effort for it. Yb: fluorophosphate glass is the only material used in a laser system, reaching an output of more than 10 TW. As is well known, the thermal blocking of Yb3+ laser is a bottleneck in laser operation, which is closely related to the Stark splitting of Yb3+ in a gain medium. Conventional Yb: phosphate glass has the advantages in Yb3+ concentration, lifetime and cross section over silicate glass, however, its small Stark splitting is the main drawback that induces difficulties in realizing laser output at room temperature. Yb:phosphate glass will be a good gain medium for high power Yb3+ laser if the Stark splitting is improved. This study focuses on the enlargement of the Yb3+ Stark splitting in phosphate glass by introducing SiO2, thereby achieving a large Stark splitting property compared with the phosphate glass. The glass 60P(2)O(5)-7.5Al(2)O(3)-15K(2)O-17.5BaO-1Yb(2)O(3) is used as the base glass, and the modified glass denoted as PS is obtained by doping a certain amount of SiO2. Such a glass is prepared by the conventional melting-quenching method. Lorentz fitting is performed to the absorption and fluorescence spectra for determining the Stark splitting scheme. Raman spectrum is used for the auxiliary judgment of the attributions of the different spectroscopic bands. Then the results are confirmed by the barycenter law of Yb3+ ion. Investigations show that the addition of SiO2 can enlarge the Stark splitting obviously from the original 670 to 771 cm(-1) in PS3. Scalar crystal field parameter N-J and asymmetry degree around Yb3+ are also increased due to SiO2 incorporation. Meanwhile, spectroscopic properties of PS series glasses, such as fluorescence effective line width (Delta lambda(eff)) and fluorescence lifetime (tau(f)), are moderately enhanced. The glass transition temperature is improved greatly, which is very valuable for high power Yb3+ laser. These results suggest that the introduction of a second network former is an effective way to enlarge the Stark splitting of Yb3+ in phosphate glass. Next, our investigation will focus on preparing the high-homogeneity SiO2 modified phosphate glasses and the corresponding laser experiments
All fiber tunable- or dual-wavelength Yb-doped fiber laser covering from dissipative soliton to dissipative soliton resonance
No full textNational High Technology Research and Development Program of China [2014AA041901]; NSAF Foundation of National Natural Science Foundation of China [U1330134]; project of Shandong Province Higher Educational Science and Technology Program [J13LJ06]; NationIn this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization rotation technique operating under dissipative soliton (DS) or dissipative soliton resonance (DSR) conditions is proposed. Furthermore, using a combination of a bandpass filter and a Loyt filter, tunable single-wavelength or dual-wavelength operation under two different conditions is realized, respectively. The tunable single-wavelength DS laser has a 5 nm tuning range from 1029 to 1034 nm with a pulse width of 110 ps. The tunable single-wavelength DSR operation laser has a range of 4 nm. In-depth research on the mechanism of the conversion between DS and DSR is carried out. Particularly, under dual-wavelength DSR operation, the obtained step-like pulses consist of two rectangular pulses with different energies. This work could help give a deeper insight into normal dispersion pulses
High Precision Time and Frequency Transfer on 275 km Beijing-Shanghai Fiber Backbone
No full text为实现准国土范围内高精度授时和守时,利用光纤传递铯钟、氢钟等高精度原子钟的时频信号,在实际光纤链路上验证其长距离传递性能。采用波分复用和双向双波长的传输方法,介绍了在275km京沪干线上实现高精度时频传递的相关工作。针对长距离光纤链路的特点,探讨了链路损耗与散射、色散与频率噪声、补偿系统动态范围和反馈带宽等对时频传递性能的影响。实验获得了频率信号的秒稳定度达5*10-14和天稳定度达7*10-18的传递性能,同时,千秒尺度下的时间方差可达2.4ps。国家自然科学基金To achieve high precision timing and punctuality in quasi national territory,time and frequency signal of high precision atomic clocks,such as cesium clock or hydrogen maser,is transferred by using fiber to examine the transfer performance of long distance on actual fiber link.By adopting the methods of wavelength division multiplexing and dual wavelength bi-directional transmitting,the related work of achieving high precision time and frequency signal is introduced on 275 km Beijing-Shanghai backbone.Based on the characteristics of long distance fiber link,the impact of loss and scattering of link,dispersion and frequency noise,feedback loop bandwidth and dynamic range of compensating system on time and frequency transfer performance is discussed.Results show that the frequency stabilities are up to 5*10-14 in one second averaging time and 7*10-14 in one day averaging time,and time synchronization stabilities are up to 2.4ps in one thousand second averaging time
Influence analysis and calibration of laser pointing for airborne Doppler lidar
No full text通过分析机载多普勒激光雷达测量模式特征,考虑飞机姿态测量精度的影响,仿真分析了径向速度误差,以及多视线反演水平风场的反演精度,按照文中仿真系统的输入参数,不考虑雷达系统频率检测误差,风速测量误差小于0.3 m/s。该结果为机载多普勒激光雷达平台设计和测量模式的选择提供了参考。在此基础上,提出了一种基于地面散射信号测量的激光指向定标方法,并通过激光雷达实测数据进行验证,指向定标精度优于0.2°。某高分项目; 国家自然科学基金项目; 山东省自然科学基金项目; 鲁东大学校基金项目The radial velocity deviation and the horizontal wind accuracy from multi view retrieval are simulated and analysed with considering the characteistics of lidar measurement mode and the influence from the accuracy of flight attitude. The resluts show the wind measurement accuracy is less than 0.3 m/s under the input values in paper and disregarding the frequency discrimination error from lidar system. This is useful for the platform design of airborne lidar and the determation of wind measurement mode. Beside these,a new method based on ground return measurement for laser pointing calibration is proposed, and the calibration accuracy is better than 0.2° through the analysis of measurement data of airborne doppler lidar
Research on the Signal-to-Noise Ratio in Sliding Spotlight Mode Down-Looking Synthetic Aperture Imaging Ladar
No full text用15m的平行光管模拟远场条件对直视合成孔径激光成像雷达(SAIL)的滑动聚束模式进行了研究。基于单点目标回波收集方程,分析了滑动聚束的信噪比特性,理论和实验证实滑动聚束模式可以通过延长有效采集时间长度的方式提高信噪比。国家自然科学基金Under far field simulated conditions by using collimator with 15 mfocal length,we present a sliding spotlight mode of the down-looking synthetic aperture imaging ladar(SAIL).Based a single point target echo collection equation,the signal-to-noise ratio in sliding spotlight mode is analysed.Theory and experiment confirm that the sliding spotlight mode can improve signal-to-noise ratio when we can extend the effective acquisition time length
基于BOTDR光纤传感技术的光缆应变测量研究
No full text光缆线路应变监测对于通信系统的安全运行及预警等具有重要的意义。利用光缆内单模光纤中的自发布里渊散射,其频移和外界应变变化呈线性关系,构建布里渊光时域反射传感系统(BOTDR)。对长57m光缆施加拉力,利用BOTDR传感技术,对光缆所承受的拉力进行测量。随着拉力增加,光缆内布里渊频移增加,所测得光纤应变增加,多次测量具有重复性。BOTDR测量结果略小于光缆拉力试验机的测量结果,其误差为1.6%,这是由应力传递引起的。实验结果表明,BOTDR传感技术能够准确的、分布式的实现光缆沿线应变监测,可为通信光缆的机械国家自然科学基金(31201377);; 郑州轻工业学院博士启动资金(2013BSJJ012、2014BSJJ086
高速伪随机码调制激光测距雷达电子学系统设计
No full text针对采用光子计数的高速伪随机码激光测距,开发了基于高性能FPGA的电子学系统。该系统将伪随机码调制信号发送、码元数据接收、累加运算、互相关运算、距离信息提取及网络通信等功能集成在单个Altera公司的Stratix IV系列FPGA芯片中。系统中采用10阶M序列伪随机码,伪随机码发送和接收速率为1 GHz,周期为10 k Hz。接收的码元经过10次累加和阈值比较后,利用1 024个并行的同或逻辑实现互相关运算。互相关运算和距离信息提取的重复频率为1 k Hz。理想条件下的测试结果表明,系统达到了设计要求。中国科学院支撑技术项目(61501010304
Flat Gauss illumination for the step-and-scan lithographic system
No full textInternational Science & Technology Cooperation Programs of China [2011DFR10010, 2012DFG51590]; Science and Technology Commission of Shanghai Municipality [14YF1406300]; National Science and Technology Major Project of China [2011ZX02402]To meet the uniform dose exposure in optical lithography, it is desirable to get uniform illumination in the scanning direction on wafer for the step-and-scan lithographic system. We present a flat Gauss illumination for the step-and-scan lithographic system in this paper. Through flat Gauss illumination in scanning direction, pulse quantization effect could be reduced effectively. Correspondingly, the uniformity of the reticle and wafer is improved. Compared with the trapezoid illumination, flat Gauss illumination could keep the slit edge fixed, and pulse quantization effect will not be enhanced. Moreover flat Gauss illumination could be obtained directly without defocusing and blocking, which results in high energy efficiency and high throughput of the lithography. A design strategy for flat Gauss illumination is also proposed which offers high uniformity illumination, fixed slope and integral energy of flat Gauss illumination in different coherence factors. The strategy describes a light uniform device which contains first microlens array, second microlens array, one-dimensional Gauss diffuser and a Fourier lens. The device produces flat Gauss illumination directly at the scanning slit. The design and simulation results show that the uniformity of flat Gauss illumination in two directions satisfy the requirements of lithographic illumination system and the slope. In addition, slit edge of flat Gauss illumination does not change. (C) 2016 Published by Elsevier B.V