光束经过三棱镜的偏向角分析

首先对偏向角的公式进行了推导,重点讨论了在有出射光线的情况下,三棱镜的规格参数、棱镜顶角和折射率对入射角和折射角的影响;然后,建立了偏向角与入射角、棱镜顶角及折射率之间的关系,并阐述了关系曲线的物理意义;最后对最小偏向角进行了研究.     

三棱镜的全反射特性研究

1 引言 文献[1]讨论了三棱镜偏向角与入射角的关系,用最小偏向角法来测量玻璃的折射率,称为三棱镜的折射特性.在实验中,如果入射光线的入射角小于"最小入射角"时,偏向角不存在,即没有出射光线,而出射光线实际上在第二个折射面上产生了全反射,称为三棱镜的全反射特性.     

最小偏向角法测三棱镜折射率的相图探究

三棱镜折射率的测量是大学物理实验的重要组成部分,对培养学生的基本实验技能、加深对经典光学理论的理解具有重要作用。本文依据几何光学原理探究了最小偏向角法中在有出射光时最小偏向角与三棱镜顶角、折射率所对应的函数关系,建立了有出射光时入射角、折射率、顶角间以及最小偏向角时折射率、顶角、最小偏向角间的相图,阐明了两相图的物理意义。该研究拓展了三棱镜折射率实验的研究思路。     

三棱镜偏向角与入射角关系的研究

根据三棱镜偏向角与入射角的关系,讨论了最小偏向角和最小入射角,为实验中掌握出射光线的移动规律,准确判断最小偏向角的位置提供了理论依据.     

模拟实验研究最小偏向角的规律

用分光计测量三棱镜折射率是一个间接测量实验,通过测量三棱镜的顶角和最小偏向角来计算获得折射率．本文通过编译程序模拟实验,描绘出偏向角随入射角、折射率变化的规律,进一步研究了最小偏向角与折射率间的对应关系．     

三棱镜偏向角与棱镜顶角的关系

从几何光学理论系统地讨论了棱镜偏向角与顶角的关系,并由Matlab绘出棱镜顶角A与棱镜最小入射角、材料折射率n的关系曲线.结果表明,在测量三棱镜折射率及使用棱镜光谱仪时,对棱镜的顶角是有一定要求的.     

恒偏向高分辨率变束棱镜光谱仪

现有的各种棱镜光谱仪器中,色散分光棱镜都采用等腰或等边棱镜(简称三棱镜),棱镜顶角一般为58-63°.这种棱镜都工作于最小偏向角状态,这时光线的出射角等于入射角,棱镜内的光线平行于底边,而出射光束宽度显然等于入射光束宽度,即两侧光束是对称的.当旋转棱镜时,满足上述条件波长的单色光即被分离出来.这就是单色仪的工作原理.对于摄谱仪器,只有一个波长工作于最小偏向角,其他则近似工作于最小偏向角,但其出射光束宽度仍等于成近似等于入射光束宽度.我们把这种等束工作的棱镜称作“等束棱镜”.至今,所有棱镜光谱仪器中的分光棱镜,均是这种棱…     

最小偏向角法和任意偏向角法准确度的初步比较

最小偏向角法和任意偏向角法准确度的初步比较蒋宁越朱鹤年（清华大学北京１０００８４）（收稿日期：１９９６０３２０）１由入射角和偏向角求折射率的公式测顶角为Ａ的三棱镜材料的折射率ｎ，传统方法是用最小偏向角法．近年来，有多篇论文讨论了用任意偏向角法测...     

基于计算机拟合的三棱镜色散率测量

利用分光计对三棱镜顶角和汞光灯、钠光灯的不同波长光线的最小偏向角进行测量,并且计算不同波长光线的折射率,再利用计算机编程拟合实验曲线,得到关于三棱镜的色散曲线,最后求导得到色散率函数。     

小入射角条件下气动光学成像偏移

针对超声速飞行器在大气中飞行时由于气动光学效应产生的成像偏移,推导了光线偏折角和流场折射率梯度之间的关系,给出了小入射角情况下,离散折射率场光线偏折角的一种计算方法;利用不同流场的计算流体力学数据计算出对应的折射率场;使用光线追迹法得到光线通过不同流场后的偏折角和传播路径上的折射率梯度分布。仿真结果表明,新的偏折角计算方法所得结果在入射角小于30°时与Runge-Kutta和Snell光线追迹法具有很好的一致性;同一高度下小入射角时,光线的偏折角并不随着飞行速度的增加而增加,而是基本保持稳定;光线通过流场的偏折是正负折射率梯度区域共同作用的结果,负的折射率梯度区域可以减少光线偏折,起到部分"校正"作用。     

五角棱镜制造角差及抖动对其转向角的影响

从五角棱镜的原理和特性出发,分析了在理想条件下五角棱镜的转向角不受入射角的影响,详细讨论由于五角棱镜加工角差和相对入射光束抖动对其转向角的影响,给出了相应的精确表达式。其中对于入射光在垂直于入射面抖动的情况,由于不能简单从二维几何光学关系分析,而采用了矢量分析方法,得出:当角差δβ=δθ时,入射角抖动对转向角偏差的影响可以忽略,而转向角偏差与制造角差几乎成线性关系。为五角棱镜用于计量测试误差分析提供了理论依据。结论对五角棱镜的制造也有很大理论指导的意义。     

Geometric formula for prism deflection

While studying neutron deflections produced by a magnetic prism, we have stumbled upon a simple ‘geometric’ formula. For a prism of refractive indexn close to unity, the deflection simply equals the product of the refractive powern − 1 and the base-to-height ratio of the prism, regardless of the apex angle. The base and height of the prism are measured respectively along and perpendicular to the direction of beam propagation within the prism. The geometric formula greatly simplifies the optimisation of prism parameters to suit any specific experiment.     

基于正解过程的Risley棱镜光束指向控制精度分析

为了获得Risley棱镜系统光束指向控制精度指标设计及性能提升的依据,对系统光束指向控制精度随轴系角度测量精度的非线性变化规律进行了研究。首先,以一级近轴近似矢量合成模型为基础,采用正解方法根据双棱镜方位推导了出射光束指向的解析表达式;然后,结合单自由度轴系伺服控制经验,通过泰勒级数展开的方式推导出了光束指向控制精度与轴系角度测量精度之间的非线性解析表达式,并由此获得了界定限判据;最后,分别对小偏向角系统和大偏向角系统进行了仿真分析,获得了光束指向控制精度在全视场区域内的变化情况。结果表明,本文研究所得的非线性解析式描述了影响系统光束指向控制精度诸多因素之间的相互关系,能够为Risley棱镜光束指向系统的设计及整体性能的优化提供依据。     

任意偏向角法测三棱镜折射率

利用任意偏向角法测三棱镜折射率,操作简单且精度较高.     

Optical refractometry based on Fresnel diffraction from a phase wedge

A method that utilizes the Fresnel diffraction of light from the phase step formed by a transparent wedge is introduced for measuring the refractive indices of transparent solids, liquids, and solutions. It is shown that, as a transparent wedge of small apex angle is illuminated perpendicular to its surface by a monochromatic parallel beam of light, the Fresnel fringes, caused by abrupt change in refractive index at the wedge lateral boundary, are formed on a screen held perpendicular to the beam propagation direction. The visibility of the fringes varies periodically between zero and 1 in the direction normal to the wedge apex. For a known or measured apex angle, the wedge refractive index is obtained by measuring the period length by a CCD. To measure the refractive index of a transparent liquid or solution, the wedge is installed in a transparent rectangle cell containing the sample. Then, the cell is illuminated perpendicularly and the visibility period is measured. By using modest optics, one can measure the refractive index at a relative uncertainty level of 10(-5). There is no limitation on the refractive index range. The method can be applied easily with no mechanical manipulation. The measuring apparatus can be very compact with low mechanical and optical noises.     

Optimized design of parallel beam-splitting prism

A large lateral shearing distance of parallel beam-splitting prism is often needed in laser modulation and polarization interference. In this letter, we present an optimized design of parallel beam-splitting prism and list some different cases in detail. The optimized design widens the use range of parallel beam-splitting prism. At the wavelength of 632.8 nm, the law that the enlargement ratio changes with the refractive index and the apex angle is verified.     

光热偏转光谱法的研究

为了建立棱镜型光热偏转光谱法的理论框架,采用棱镜的光色散特性研究了激励光源对待测样品表面周期性照射情况下的探测光偏转角与光热信号之间的解析关系。得到了棱镜型样品表面周期性变化的偏转角表达式。实现结果表明,该方法比传统型光谱法具有理论模型简单、实验容易实现、分辨率高、灵敏度高等优点。     

Simultaneous determination of the X-ray refractive index and the attenuation length from a single digitally registered radiograph of rectangular prisms

Prisms deflect and disperse X-rays due to refraction very similar to visible light. As X-rays are always attenuated while traversing material, the intensity distribution in the transmitted beam carries information about the prism transmission function. This study will show that sufficient information is contained in a single digitally registered radiograph from a rectangular prism, for deriving both the refractive index of the material and its attenuation length. The measured data can be prepared such that neither intensity fluctuations nor false light content in the incident beam will introduce systematic errors into the result. The strategy is thus very adapted, when single shot pictures are taken at X-ray sources with limited shot reproducibility. This technique is favourably be used at very grazing angles of incidence of the order of the critical angle for the prism material, when the beam deflection becomes significant. In such a geometry dimensional parameters, like sample thickness, do not affect the data analysis, which is particularly insensitive to even significant errors in the tip angle.