太阳能槽式聚光反射镜自动跟踪装置

在分析太阳运行规律的基础上,提出一种太阳跟踪的新方案。描述了槽式聚光反射镜自动跟踪装置的机械结构及跟踪控制的原理、方法,给出具体应用实例。槽式聚光装置的应用前景十分广泛,可用于太阳能制冷、供暖、海水淡化等各种生产、生活领域。

拉曼光反射镜隔振平台设计及性能测试

为提高原子干涉重力仪拉曼光相位稳定性,降低拉曼光反射镜振动噪声对原子干涉仪测量精度的影响,设计并研制了一种适用于小型化原子干涉重力仪拉曼光反射镜隔振平台。通过COMSOL Multiphysics有限元分析和激光干涉仪测试验证了其隔振性能。根据原子干涉重力仪对噪声控制的要求,对隔振平台在60~200 Hz内的减振效果进行仿真,将仿真结果作为试验的指导,用扫描式激光干涉仪配合标准振动台,对装载到隔振平台上的拉曼光反射镜的振动进行了测试,结果符合仿真结论。

多层膜软X光反射镜

复旦大学物理系激光研究室从1984年开始软X光反射镜的研制工作。六年来,进行了超薄多层膜的膜厚监控的方法研究、单层超薄金属膜的特性研究、Ni-C和Mo-Si多层膜软X光反射镜的制备与测试以及用PVD与LB技术相结合制备软X光反射镜。本文详细介绍了这些工作。

高反射率、低温度敏感性的片上光反射镜

反射镜作为光子集成电路的基本元件,被应用于量子通信、智能电网、航空航天等多种领域。高反射率、低温度敏感性的片上光反射镜可以大大简化光子集成电路系统,提高光子集成电路的可靠性和稳定性。因此,提出了一种基于绝缘体上硅的高反射率、低温度敏感性片上光反射镜方案。该方案采用Sagnac环结构,可在3.41 nm波长范围内实现超高反射率(反射率大于90%),在32.85 nm波长范围内实现高反射率(反射率大于80%)。通过片上微型热电极对该反射镜进行加热,结果表明,当微型热电极的功率从0 mW逐渐升高至6 mW时,在1566.5~1568.58 nm波长范围内反射镜的波长漂移量小于0.045 nm,反射率变化小于0.19 dB。该反射镜具有尺寸小、质量轻、制造简单、反射率高、损耗小、温度不敏感等优势,可广泛应用于激光器、微波光子滤波器、光传输网等通信和信号处理领域。

X光多层膜反射镜的损伤与破坏实验研究

产生 Ｘ 光激光的等离子体环境对 Ｘ 光多层膜反射镜造成损伤与破坏。通过模拟实验，给出国产 Ｍｏ／ Ｓｉ多层膜反射镜的破坏阈值大约是 ０１０ Ｊ／ｃｍ ２，在这个辐照剂量下，多层膜表面均方粗糙度明显增加，反射率几乎降至为零。提出了防止多层膜反射镜破坏的一些想法。

一种基于波分复用的光控波束合成网络

提出了一种基于波分复用光控波束合成网络,其核心是采用了由波分复用器、可调衰减器和光反射镜构成的光延时模块,通过光反射镜的光程调节获得通道之间的延时。根据该方案制作了18 GHz工作频率下,波束指向为0°和-45°的两个16通道光延时模块。测试结果表明,模块的相位精度达到了±15°,幅度一致性优于±0.1 dB,仿真方向图显示了较高的波束指向精度。

C/SiC复合材料空间光机结构的研究进展与展望

C/SiC具有轻质、高模、低热膨胀系数等优异的性能,可作为新一代高精度空间光机结构件材料。概述了空间光机结构件材料发展的趋势,对比了RB、CVI、PIP工艺的C/SiC复合材料性能,综述了近年来国内外C/SiC复合材料在空间光机结构中的研究进展及应用情况,指出低成本、短周期、结构和工艺设计以及应用基础研究将是C/SiC复合材料未来发展的重点方向。

物面分波前反射镜位移调制参考光双曝光全息

研究物面分波前反射镜运动调制参考光双曝光全息测量物体位移方向的理论与方法。在两次曝光全息图的记录过程中,置于物面的分波前反射镜作微位移,则该反射镜反射的参考光被反射镜运动所调制,由此记录的双曝光全息干涉图不仅含有物体位移数值的信息,而且还含有位移方向的信息。通过理论分析,建立了当观察点移动时这类双曝光干涉图上干涉条纹的移动方向与物体位移方向及分波前反射镜位移方向之间的相互关系和基本规律,导出了相关公式,并确立了测量物体位移方向的方法,给出了实验结果。

对基于拼接干涉术的同步辐射镜测量技术的研究

随着同步辐射光源和自由电子激光器相关技术的发展和光束质量的提升,对用于转递和聚焦光束能量的X光反射镜的指标要求也逐渐提高。为避免引入额外的波前误差,反射镜面形高度误差均方根值的要求已逼近至亚纳米量级。如此苛刻的面形要求对X光反射镜的测量工作带来了极大的困难和挑战。除了在各国同步辐射光源得到广泛使用的长程轮廓仪等基于角度测量的轮廓扫描仪器之外,基于激光干涉仪的拼接干涉技术也发展为测量同步辐射镜的一种有效手段。文中主要介绍了近期笔者等为测量X光反射镜而开发的拼接干涉平台。利用这一测量平台,研究了在不同的拼接参数下的多种拼接模式。着重讲述了其中纯软件拼接模式的基本原理和实际测量。用实测结果与不同测量仪器和不同研究机构的结果进行比对,验证了拼接干涉测量用于检测同步辐射镜的有效性,并展示了此拼接平台的测量表现。根据所得的测量数据看来,使用纯软件拼接模式来测量X光平面反射镜时,测量重复性的均方差值可以达到0.1 nm左右;而测量X光双曲柱面镜时(曲率半径的变化范围为50~130 m),测量重复性的均方差值为0.2~0.3 nm。此结果基本满足平面和接近平面(曲率半径大于50 m)的同步辐射镜常规检测和为确定性加工提供面形反馈的需要。

杨氏弹性模量测定中一种引发误差的分析

杨氏弹性模量的测定是大学工科物理实验课的基础实验之一。通过光杠杆反射镜面、竖尺偏调产生误差的分析 ,引起对实验条件满足的程度及其对结果影响等实验方法和思想的讨论。

Optimization for Top DBR’s Reflectivity in RCE Photodectector

The monolithic integration of vertical-cavity surface-emitting lasers (VCSEL) with photodetectors is very important in the application of free-space optical interconnects.Theoretical and experimental results on the resonant-cavity-enhanced (RCE) photodetector with VCSEL Structure are presented.The compatible requirement in input mirror reflectivity between the VCSEL and the RCE detector is achieved by precisely etching the top mirror.In this way,the RCE detector with relatively high quantum efficiency and necessary optical bandwidth has been obtained.[KH8/9D]

Effects of quasi-periodicity on defect modes of photonic crystals

In this letter,the effects of Bragg-mirror quasi-periodicity on the shifts and quality factor in defect modes of photonic crystals are studied by using the transfer matrix method.Furthermore the influence of the quasi-periodicity on electric field enhancement effect inside the defect layer is studied,which is similar to that on the quality factor.

CHARACTER OF RETROREFLECTOR’S LIGHT FIELD’S ENERGY DISTRIBUTION AND ITS MEASURING TECHNOLOGY

The formation of the retroreflected light field is introduced in the paper and the components of the retroreflected light field are analyzed.Furthermore,a deep analysis of the factors affecting energy distribution of the retroreflected light,such as design deviation,angle of incidence,was made.The simulation of the retroreflected light field was done.Recommendation is made in detail on both the energy distribution of the retroreflected light field at different working distances and the energy distribution of the retroreflected light field at a short distance when the diverging light comes.At last,two kinds of measuring instrument for the retroreflector are introduced,one is the long tunnel measuring instrument,the other is the minitype measuring instrument based on the character of the retroreflector when the diverging light comes.

Design of fiber-optic collector for spectrometer based on curved mirror

To enlarge the detection range of traditional fiber-optic spectrometer,two rotating parabolic mirrors were first used in the design of fiber-optic collector for spectrometer,which can extend the detection range of spectrometer from centimeter-scale to50m,as a super-low altitude remote sensing detector under passive lighting conditions.According to the performance requirements of fiber-spectrometer for optical collector,this study deduced the calculation formulae of design size of parabolic optical collector applied to different sensitivity spectrometers,different detection targets,different detection ranges and different weathers.Based on the calculation results,the model of fiber-optic collector with a diameter of16mm and a height of7.8mm was designed by ZEMAX.And then,TracePro,a light simulation software,was applied to ray tracing.The simulation results of optical radiation magnification agrees well with theoretical value,and the relative error is less than0.78%.This optical collector can effectively extend the detection range of spectrometer and expand its application fields and scopes.Compared with traditional refractive optical collector,it has several advantages of compact structure,low weight and low cost.

Improvement of visible light-induced photocatalytic performance by Cr-doped SrTiO_3-carbon nitride intercalation compound (CNIC) composite

Novel organic-inorganic composite photocatalyst offers new opportunities in the practical applications of photocatalysis. Novel visible light-induced Cr-doped Sr Ti O3–carbon nitride intercalation compound(CNIC) composite photocatalysts were synthesized. The composite photocatalyst was characterized by X-ray diffraction(XRD), field-emission scanning electron microscopy(FESEM), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy, and BET surface area analyzer. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. For maximizing the photodegradation activity of the composite photocatalysts, the optimal CNIC content was determined. The improved photocatalytic activity of the as-prepared Cr-doped Sr Ti O3–CNIC composite photocatalyst may be attributed to the enhancement of photo-generated electron–hole separations at the interface.

Ultra-precision machining of reflector array for laser diode beam shaping

Ultra-precision machining is an effective approach to achieve high dimension accuracy and surface finish required in optical and laser components. An extensive study using a two-axis diamond turning machine is conducted to machine the reflector arrays used for laser diode beam shaping. To position the workpiece precisely, theoretical analysis is made so that the dimensional accuracy can be achieved. Investigations into machining burr reduction are carried out. With the process developed, reflectors with optical surface finish of 8 nm in Ra and minimized burr size of less than 0.5 μm have been achieved.

Laser Cleaning of Mirror Surface for Optical Diagnostic Systems of the International Thermonuclear Experimental Reactor

The development of cleaning optics and deposition-mitigating techniques is a key factor in the construction and operation of optical diagnostics in ITER. The cleaning of optical surface by pulsed radiation from a fiber laser is an effective method that can recover optical properties of the mirror surface. The possibility of cleaning metallic mirrors from films with complex composition by pulsed radiation from a fiber laser has been experimentally researched. It has been shown that the high initial reflection characteristics of optical elements can be recovered by choosing regimes of radiation effect on the deposited surface. Efficient cleaning is ensured by radiation with the power density of less than 107 W/cm2. At this relatively low power density, pollutions are removed in a solid phase and the thermal effect on the mirror is insignificant. Preliminary experiments of the metal mirrors cleaning by fiber laser radiation have demonstrated the possibility of hardware implementation techniques.

Study on optical compound films

Using the compound materials and double e-gun evaporation,the compound optical films have been successfully deposited on K9 glass substrate.The refractive index of optical compund films deposited in diffeent parameters have been measured and theoretical formula for calculation refractive index of compound films have been derived.It is shown that the experimental curve for the variation of refractive index with wavelength in 0.4￣1.4 μm region and the theoretical one agree very well.Using these films,the laser reflecting mirror has been successfully coated.

Three-dimensional tracking of GLUT4 vesicles in TIRF microscopy

TIRF microscopy has provided a means to view mobile granules within 100 nm in size in two dimensions.However quantitative analysis of the position and motion of those granules requires an appropriate tracking method.In this paper,we present a new tracking algorithm combined with the unique features of TIRF.Firstly a fluorescence correction procedure was processed to solve the problem of fluorescence bleaching over time.Mobile granules were then segmented from a time-lapse image stack by an adaptive background subtraction method.Kalman filter was introduced to estimate and track the granules that allowed reducing searching range and hence greater reliability in tracking process.After the tracked granules were located in x-y plane,the z-position was indirectly inferred from the changes in their intensities.In the experiments the algorithm was applied in tracking GLUT4 vesicles in living adipose cells.The results indicate that the algorithm has achieved robust estimation and tracking of the vesicles in three dimensions.

Evaluation of cable tension sensors of FAST reflector from the perspective of EMI

The active reflector of FAST （ five-hundred-meter aperture spherical radio telescope） is suppor- ted by a ring beam and a cable-net structure, in which nodes are actively controlled to form series of real-time paraboloids. To ensure the security and stability of the supporting structure, tension must be monitored for some typical cables. Considering the stringent requirements in accuracy and long- term stability, magnetic flux sensor, vibrating wire strain gauge and fiber bragg grating strain gauge are screened for the cable tension monitoring of the supporting cable-net. Specifically, receivers of radio telescopes have strict restriction on electro magnetic interference （EMI） or radio frequency in- terference （RFI）. These three types of sensors are evaluated from the view of EMIfRFI. Firstly, these fundamentals are theoretically analyzed. Secondly, typical sensor signals are collected in the time and analyzed in the frequency domain, which shows the characteristic in the frequency domain. Finally, typical sensors are tested in an anechoic chamber to get the EMI levels. Theoretical analysis shows that Fiber Bragg Grating strain gauge itself will not lead to EMI/RFI. According to GJB151 A, frequency domain analysis and test results show that for the vibrating wire strain gauge and magnetic flux sensor themselves, testable EMIfRF1 levels are typically below the background noise of the ane- choic chamber. FAST finally choses these three sensors as the monitoring sensors of its cable ten- sion. The proposed study is also a reference to the monitoring equipment selection of other radio tele- scopes and large structures.