液晶波前校正器校正水平方向上的大气湍流

利用液晶波前校正器和哈特曼波前传感器组成的自适应光学系统对水平方向500 m的大气湍流进行校正.首先测定了液晶波前校正器(LCWFC)的位相调制特性,测定结果表明其可以实现一个波长的调制量,同时利用Garoma校正实现了位相和灰度之间的线性调制关系.然后将该系统与孔径220 mm的望远镜进行对接.液晶自适应校正后,波面均方根误差降低到0.06λ,实现了0.68"的系统衍射极限分辨.实验结果表明:液晶波前校正器可以很好地校正水平方向500 m的大气湍流扰动.     

中科院长春光机所液晶光学研究团队

正中科院长春光机所液晶光学研究团队由1999年中科院"百人计划"引进的人才宣丽研究员组建。目前有固定人员13人,其中:研究员4人,副研究员5人,助理研究员1人,工程师1人,研究实习员2人,在读研究生25人。研究方向以基于液晶波前校正器的自适应光学(AO)成像为主,应用于大口径望远镜和人眼视网膜检查设备。"十一五"期间,先后完成国家自然基金重点项目"可见-近红外宽波段快速液晶自适应系统的研究"、863"十一五"规划重点项目液晶自适应波面校正系统,攻克了液晶波前校正器响应速度慢、偏振能     

中科院长春光机所液晶光学研究团队

正中科院长春光机所液晶光学研究团队由1999年中科院"百人计划"引进的人才宣丽研究员组建。目前有固定人员13人,其中:研究员4人,副研究员5人,助理研究员1人,工程师1人,研究实习员2人,在读研究生25人。研究方向以基于液晶波前校正器的自适应光学(AO)成像为主,应用于大口径望远镜和人眼视网膜检查设备。"十一五"期间,先后完成国家自然基金重点项目"可见-近红外宽波段快速液晶自适应系统的研究"、863"十一五"规划重点项目液晶自适应波面校正系统,攻克了液晶波前校正器响应速度慢、偏振能     

中科院长春光机所液晶光学研究团队

正中科院长春光机所液晶光学研究团队由1999年中科院"百人计划"引进的人才宣丽研究员组建。目前有固定人员13人,其中:研究员4人,副研究员5人,助理研究员1人,工程师1人,研究实习员2人,在读研究生25人。研究方向以基于液晶波前校正器的自适应光学(AO)成像为主,应用于大口径望远镜和人眼视网膜检查设备。"十一五"期间,先后完成国家自然基金重点项目"可见-近红外宽波段快速液晶自适应系统的研究"、863"十一五"规划重点项目液晶自适应波面校正系统,攻克了液晶波前校正器响应速度慢、偏振能     

中科院长春光机所液晶光学研究团队

<正>中科院长春光机所液晶光学研究团队由1999年中科院"百人计划"引进的人才宣丽研究员组建。目前有固定人员13人,其中:研究员4人,副研究员5人,助理研究员1人,工程师1人,研究实习员2人,在读研究生25人。研究方向以基于液晶波前校正器的自适应光学(AO)成像为主,应用于大口径望远镜和人眼视网膜检查设备。"十一五"期间,先后完成国家自然基金重点项目"可见-近红外宽波段快速液晶自适应系统的研究"、863"十一五"规划重点项目液晶自适应波面校正系统,攻克了液晶波前校正器响应速度慢、偏振能     

中科院长春光机所液晶光学研究团队

<正>中科院长春光机所液晶光学研究团队由1999年中科院"百人计划"引进的人才宣丽研究员组建。目前有固定人员13人,其中:研究员4人,副研究员5人,助理研究员1人,工程师1人,研究实习员2人,在读研究生25人。研究方向以基于液晶波前校正器的自适应光学(AO)成像为主,应用于大口径望远镜和人眼视网膜检查设备。"十一五"期间,先后完成国家自然基金重点项目"可见-近红外宽波段快速液晶自适应系统的研究"、863"十一五"规划重点项目液晶自适应波面校正系统,攻克了液晶波前校正器响应速度慢、偏振能     

液晶波前校正器位相调制非线性及闭环校正研究

研究了液晶波前校正器位相调制曲线非线性的校正以及液晶自适应闭环对畸变波前的校正.利用液晶显示器领域通用的Gamma校正技术实现对液晶波前校正器非线性的校正.首先,通过施加线性的LUT曲线以获得512个LUT值对应的位相调制量.然后通过对一个波长位相调制量的线性化分割,找到能够获得线性位相调制的LUT函数曲线.最后将该优化曲线写入液晶波前校正器的驱动电路板中,再次驱动液晶波前校正器并利用ZY-GO干涉仪测量位相调制和灰度级的关系,得到了线性的位相调制.利用线性的液晶波前校正器结合哈特曼波前探测器和波前控制器进行了自适应闭环校正研究.校正前,PV和RMS的平均值分别为2.5牒.48耄痪栈纷允视πＵ琍V和RMS的平均值分别下降为和.分辨率板的一级像也由模糊变得清晰.实验结果说明,经过线性化的液晶波前校正器可以获得高校正精度.     

望远镜的紧凑型闭环液晶自适应光学系统设计

在利用地基大口径光学望远镜进行天文观测时,液晶自适应光学成像技术已经被应用于校正大气湍流所引起的波前像差。应用Zemax软件和尽量少的光学元件,设计出了与1200mm望远镜匹配的紧凑型闭环液晶自适应光学系统。针对本套闭环自适应光学系统自身的特殊要求,制定了具体的公差原则,并应用Zemax软件进行了公差分析,结果表明,本套闭环液晶自适应光学系统具备较宽松的公差条件,可以实现较容易的加工和装调。对该紧凑型闭环液晶自适应光学系统与1200mm望远镜对接匹配后的性能进行了相应的评价:自适应光学系统与1200mm望远镜对接匹配后的组合焦距为19.13m,F数为17.92,P-V值为0.122λ,RMS值为0.031λ,MTF曲线接近衍射极限,光学传递函数的模在33lp/mm时可以达到0.5,而成像CCD的极限分辨率为31lp/mm,充分地利用了CCD相机的分辨资源。     

开环液晶自适应光学系统:研究进展和结果

对于自适应光学系统,液晶波前校正器是一个非常有前景的波前校正器件。传统的向列相液晶波前校正器的主要缺点是偏振依赖和工作波段窄。采用了基于偏振分束器的开环光路设计和优化的能量分割方法来分别解决上述问题。结果显示,开环光路非常适合于液晶波前校正器,且新颖的能量分割方法显著提高了液晶自适应光学系统的探测能力。     

液晶波前校正器动态位相响应特性研究

为了对畸变波前进行精确校正,研究了液晶波前校正器在不同灰度级之间的动态位相响应特性,准确确定其响应时间。首先给出液晶波前校正器的响应时间和位相变化的检测方案。然后检测了液晶波前校正器在0和255灰度级之间的上升和下降时间,分别为7ms和11ms。在保证校正精度的条件下,对该位相曲线采取λ/10的误差截断,使上升和下降时间分别减少到4ms和6.8ms。最后,研究了各灰度级依次上升到255和从255再以次回落到各灰度级的动态响应时间。结果表明,各灰度级的上升时间在2～5.2ms之间变化,下降时间在3.66～8.74ms之间变化,且无论是上升还是下降,150和255灰度级之间转换速度最快,在255灰度级邻近的灰度响应速度最慢,且响应时间长于0和255灰度之间的响应时间。因此,在波前校正中,须以255灰度邻近的灰度级中最长的响应时间作为液晶波前校正器的响应时间,以确保波前校正精度。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.