共查询到20条相似文献,搜索用时 406 毫秒
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菱体型相位延迟器是高度消色差的λ/4相位延迟器.由于材料折射率色散的影响,在可见光范围内,仍存在2°的延迟偏差.为满足精确应用和测量的需求,从相位延迟的全反射相变理论出发,阐述了斜入射相位延迟原理,以菲涅耳菱体为例,分析了菱体型相位延迟器相位延迟随其入射角变化的规律性,结果表明:当光线非严格准直时,光的入射角对相位延迟量有明显的影响,延迟量不但对入射角变化敏感,而且还与入射光线的入射方位密切相关,呈不对称形式.当入射光的波长改变时,只需改变菱体延迟器的方位,让光线在菱体的前端面上斜入射,适当选取入射角,就可以补偿相位延迟的色散偏差,使同一菱体达到对不同波长都满足λ/4相位延迟.当角度调整精度Δi=±0.01°时,引入的延迟偏差不超过±0.009°,这一精度是其它石英波片或云母波片所不能比的. 相似文献
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为了实现对波片快轴方位角和延迟量参数快速、高精度测试,提出了一种基于双弹光级联差频调制的波片参数测量方案。选用两个工作频率不相同的弹光调制器级联,构成偏振分析测量装置。波片的两个参数被加载到偏振分析装置的调制信号中,采用数字锁相技术同时提取调制信号的基频项和差频项,然后完成波片全部参数求解。按照原理分析,搭建了实验系统,并完成了系统初始偏移值定标,完成了632.8 nm的1/4波片,532 nm的1/4波片和1/2波片实验测量。实验结果表明,本文方案的快轴方位角测量最大偏差为0.2°,角度测量标准偏差为0.02°;波片的相位延迟量标准偏差优于5.64×10-4 rad,单点数据测量时间仅为200 ms。考虑到波片材料的双折射色散,根据检测激光波长下测量的相位延迟量,进一步计算出应用波长的波片延迟量。测量值与理论值最大偏差不超过1.17 nm,延迟精度优于λ/300。本文方案实现了高速、高精度和高灵敏的波片参数测量,可为波片加工测试和实验定标提供有效手段。 相似文献
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四区域法消除偏振棱镜缺陷对波片相位延迟测量的影响 总被引:1,自引:0,他引:1
在起偏器-待测波片-检偏器系统基础卜提出一种四区域测量波片相位延迟量的方法.调整待测波片和检偏器的方位角,获得相应的四组光强值,通过线性运算得到待测波片的相位延迟量,完全消除了起偏器和检偏器不完全消光带来的误差.由于测量系统中不存在标准波片或其他相位调制元件,允许测量波长仅受偏振棱镜和探测器的限制,因此四区域法可适用于很大波长范围内的波片测量.以λ/4波片为例,理论分析了测量系统利用四区域测量法后的仪器误差为σφ≤士3.49065×10-3rad(约0.2°),精度比原算法提高约1个数量级.实验验证了四区域法能有效提高系统精度. 相似文献
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利用自发四波混频测量光子晶体光纤色散 总被引:4,自引:1,他引:3
使用脉宽为1.6ps的脉冲光抽运0.6m长的光子晶体光纤,测量由光纤中自发四波混频过程所产生光子对的频谱,并利用所获得的相位匹配数据确定了待测光纤的色散。当抽运光的中心波长以1nm的步长,在1037~1047nm的范围内变化时,通过可调谐滤波器和单光子探测器测量光子晶体光纤产生的信号和闲频光子对的频谱,从而获得11组四波混频相位匹配数据。然后使用阶跃有效折射率模型对所获得的相位匹配数据进行拟合,得出待测光子晶体光纤的纤芯半径和包层空气比的有效值分别为0.949μm和29.52%,并在此基础上计算了光纤的色散及全频谱范围内的四波混频相位匹配曲线。实验结果显示,曲线预测值与实测值之间误差小于0.1%。 相似文献
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讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系,指出引力场强g并不是与r的平方成反比,这是由于银河系的大小和形状不能忽略造成的.强调了万有引力定律的适用条件. 相似文献
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SJ Rose 《Contemporary Physics》2013,54(2):109-121
In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required. 相似文献
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论Gibbs方程的热力学本性及热力学函数的物理意义 总被引:8,自引:2,他引:6
对Gibbs方程的热力学本性作了再认识,论述了热力学函数U、H、A、G的物理意义,尝试从一般的运动和势能的关系上理解热力学. 相似文献
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Design and analysis of the tunnel connecting the beamcorridor and the spectrum hall of the CSNS 总被引:1,自引:0,他引:1
There is a tunnel connecting the beamcorridor and the target station in the spectrum hall in the CSNS project. The length of the tunnel is about 20 m. The shielding design of the tunnel is very significant for the persons working in the spectrum hall because the tunnel is not covered by soil for shielding. In order to reduce the dose rate at the exit of the cable ducts, we use the ISIS construction, which is designed with four turnings, as a reference for the tunnel design. The thickness of the shielding is obtained by a simulation with the Monte Carlo Code FLUKA. The result is compared with the data obtained with Moyer Mode and the reliability of the simulation is proved. This paper provides the basis for the design of the tunnel. 相似文献
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Using the property of the simplest invariant built from the covariant derivatives of the curvature tensor to change sign on the Schwarzschild horizon, and the relativistic quadratic geodesic deviation equation to express the invariant in terms of locally measurable quantities, viz., separation, relative velocity and acceleration of test particles, a scheme is presented which can, in principle, be used by an imaginary observer to detect by local measurements the passage through the event horizon in the Schwarzschild spacetime. 相似文献
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We have just entered a period during which we expect considerable progress toward understanding CP violation. Here we review
what we have learnt so far, and what is to be expected in the near future. To do this we cover the foundation of CP violation
at a level which can be understood by physicists who are not working in this field. 相似文献
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It is generally believed that the laws of thermodynamics govern superconductivity as an equilibrium state of matter, and hence that the normal-superconductor transition in a magnetic field is reversible under ideal conditions. Because eddy currents are generated during the transition as the magnetic flux changes, the transition has to proceed infinitely slowly to generate no entropy. Experiments showed that to a high degree of accuracy no entropy was generated in these transitions. However, in this paper we point out that for the length of times over which these experiments extended, a much higher degree of irreversibility due to decay of eddy currents should have been detected than was actually observed. We also point out that within the conventional theory of superconductivity no explanation exists for why no Joule heat is generated in the superconductor to normal transition when the supercurrent stops. In addition we point out that within the conventional theory of superconductivity no mechanism exists for the transfer of momentum between the supercurrent and the body as a whole, which is necessary to ensure that the transition in the presence of a magnetic field respects momentum conservation. We propose a solution to all these questions based on the alternative theory of hole superconductivity. The theory proposes that in the normal-superconductor transition there is a flow and backflow of charge in direction perpendicular to the phase boundary when the phase boundary moves. We show that this flow and backflow explains the absence of Joule heat generated by Faraday eddy currents, the absence of Joule heat generated in the process of the supercurrent stopping, and the reversible transfer of momentum between the supercurrent and the body, provided the current carriers in the normal state are holes. 相似文献
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Design and analysis of the tunnel connecting the beamcorridor and the spectrum hall of the CSNS 下载免费PDF全文
There is a tunnel connecting the beamcorridor and the target station in the spectrum hall in the CSNS project.The length of the tunnel is about 20 m.The shielding design of the tunnel is very significant for the persons working in the spectrum hall because the tunnel is not covered ed soil for shielding.In order to reduce the dose rate at the exit of the cable ducts,we use the ISIS construction,which is designed with four turnings,as a reference for the tunnel design.The thickness of the shielding is obtained by a simulationwith the Monte Carlo Code FLUKA.The result is compared with the data obtained with Moyer Mode and the reliability of the simulation is proved.This paper provides the basis for the design of the tunnel. 相似文献
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We reanalize the recently proposed proof by Jensen and Stein-Schabes [1] of the No Hair Theorem for inhomogeneous spacetimes, putting a special emphasis on the asymptotic behaviour of the shear and curvature. We conclude that the theorem only holds locally and estimate the minimum size a region should be in order for it to inflate. We discuss in some detail the assumptions used in the theorem. In the last section we speculate about the possible measure of the set of spacetimes that would undergo inflation. 相似文献