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1.
激光位移传感器的光学系统设计   总被引:1,自引:0,他引:1  
莫仁芸  朱万彬  钟俊  陈璇 《中国光学》2010,3(5):513-517
针对目前国内自主研制的激光位移传感器精度低,测量范围小等问题,提出了一种采用光学设计软件预先仿真整个激光位移传感器光学系统的方法。在分析系统各部分的光学特性的基础上,结合具体要求设计了一个激光位移传感器的光学系统,其工作范围为(50±10)mm。采用系统分割的方法,将整个光学系统分为两部分进行设计,第一部分是激光束的整形透镜,要求在有效的工作范围内得到小而均匀的出射光斑,设计结果表明,在测量范围内,光斑大小能够控制在10-1mm量级;另一部分是被测面散射光接收的成像物镜,该系统的特点是物面和像面相对于光轴都有一定的角度,实验结果表明其成像满足Scbeimpflug条件。  相似文献   

2.
平行光束或者激光束在光轴方向上照射焦平面成像系统时会产生猫眼效应,焦平面探测器安装的正交性与离焦量直接影响猫眼回波的光学特性,进而影响基于猫眼效应的探测系统的性能。针对猫眼效应中离焦量与后向反射光束发散角之间关系,利用物理光学进行分析,建立理论模型,对焦距为0.18 m的焦平面探测成像系统进行数值计算得到:在离焦量为0.16 mm时,发散角最小(0.019 mrad)。搭建实验系统,测试离焦量与猫眼回波发散角,测得离焦量在0.15 mm附近存在最小的发散角为0.025 mrad,与计算结果0.019 mrad基本吻合。研究表明:1) 负离焦对发散角的影响大于正离焦;2) 猫眼回波发散角基本上随着离焦量绝对值的增加而变大,但是变化曲线并不关于零离焦量点对称,而是在某个正离焦处存在一个最小发散角。  相似文献   

3.
The Faraday rotation of the plane of polarisation of a probe beam by azimuthal magnetic fields in the presence of beam deflection caused by refractive index gradients is discussed for a plasma carrying an axial current. A method for calculation of the magnetic field profile from experimental data is described. Bθ can be found by Abel inversion if the electron density is known and if deflected rays can be collected by an optical system and focussed onto a detector. Typical Faraday rotations calculated for the Bennett pinch assuming small beam deflection are found to be proportional to the plasma current and to the angle of deflection. If the probe beam wavelength is chosen to satisfy the approximate relation N0λ2 ≈ 3.5 × 1013 m-1, where N0 is the electron density on the axis, measurement of Bθ with beam deflections less than 2 × 10-2 radians should be possible in cases where small rotations can be detected in the mid-to-far infra-red part of the spectrum.  相似文献   

4.
同时实现多角度非垂轴面均匀照明的衍射光学器件   总被引:2,自引:1,他引:1  
本文利用长焦深器件设计思路,提出了通过设计衍射光学器件相位分布使得在三个垂轴面上满足均匀照明要求来间接实现非垂轴面均匀照明的设计方法,并完成了同时实现多种角度非垂轴面均匀照明的衍射光学器件设计.基于爬山法和模拟退火法相结合的混合算法,设计了器件的相位分布,在30°、45°、55°非垂轴面上光斑不均匀性分别为5.91%、4.00%、3.38%.该方法可推广至二维情形,实现任意曲面均匀照明的要求.  相似文献   

5.
无像差的光学相机的成像模型可由其共轭节面模型等效表示。针孔模型本身忽略了偏离该等效模型的误差,也无法表示平板玻璃的平移误差、光轴的安装误差以及实际相机光学系统的像差,这四个因素都会引起图像畸变。基于此利用共轭节面的性质建立了一种图像畸变几何模型,并与广泛采用的像差模型进行了对比,从理论上解释了像差模型各个系数的物理意义。对某实际针孔相机进行仿真分析,该几何模型给出的相对径向畸变、角度误差在设计参数的范围以内,并且可以模拟图像的非对称畸变。该几何模型需要辨识包含主面相关参数、光轴倾斜角和平板玻璃的轴向球差在内的4个参数,辨识参数较少,理论上可以作为一种新的图像畸变校正方法。  相似文献   

6.
Poon AW  Chang RK  Lock JA 《Optics letters》1998,23(14):1105-1107
Spiral morphology-dependent resonances have been observed in a tilted optical fiber. The polarization-preserving and the cross-polarized elastic-scattering spectra for plane-wave illumination show that the wavelengths of the resonances are blueshifted quadratically as the fiber tilt angle increases. When a focused Gaussian beam illuminates the fiber at its edge, the resonances are blueshifted and broadened as the detector is offset from the scattering plane with the maximum scattering intensity. The blueshift with focused beam illumination is also a consequence of the spiral resonances.  相似文献   

7.
Possibilities of standard multiangle monochromatic ellipsometry in the determination of parameters of a uniform biaxially anisotropic layer are studied for the case of an arbitrary orientation of the two principal axes in the plane of incidence of the light beam and perpendicularity of the third axis to the plane of incidence. Using numerical simulation, it has been found that the measurement accuracy that is necessary in the determination of all the three principal components of the dielectric permittivity tensor ε and tilt angle of the axes using only angular dependences of ellipsometric parameters must be no worse than 0.0001°, which is far beyond the accuracy limits provided by present-day ellipsometers. If the tilt angle is known, standard multiangle monochromatic ellipsometry provides the determination of thickness and all three principal components of the dielectric permittivity tensor. This method allows one to determine the layer thickness and tensor component for the axis perpendicular to the plane of incidence, as well as the average value of components for the axes lying in the plane of incidence without involving the data about the tilt angle of the axes. This is demonstrated by an example of experimental data for biaxially anisotropic SiO x films obtained by oblique deposition of silicon monoxide SiO evaporated in vacuum.  相似文献   

8.
The coherent reflectivity of a dense, relativistic, ultra-thin electron layer is derived analytically for an obliquely incident probe beam. Results are obtained by two-fold Lorentz transformation. For the analytical treatment, a plane uniform electron layer is considered. All electrons move with uniform velocity under an angle to the normal direction of the plane; such electron motion corresponds to laser acceleration by direct action of the laser fields, as it is described in a companion paper [Eur. Phys. J. D 55, 433 (2009)]. Electron density is chosen high enough to ensure that many electrons reside in a volume λR 3, where λR is the wavelength of the reflected light in the rest frame of the layer. Under these conditions, the probe light is back-scattered coherently and is directed close to the layer normal rather than the direction of electron velocity. An important consequence is that the Doppler shift is governed by γx=(1-(Vx/c)2)-1/2 derived from the electron velocity component Vx in normal direction rather than the full γ-factor of the layer electrons.  相似文献   

9.
刘华 《中国光学》2016,9(2):277-283
衍射光学元件由于可以实现对高斯光束的整形而被重视,其通常的设计方法为G-S算法,由于使用傅里叶变换运算量大、费时长,将快速汉克尔变换应用到这些算法中可以极大地提高运算速度,节省运算时间,为设计复杂的光束整形元件提供了高效、可行的方法。本文利用该种方法设计针对中心波长为775 nm、光束束腰口径为6 cm的激光器,成功设计了一个具有二阶相位的折衍混合光学元件。仅单独这一片元件,既可在距离其35 m处得到一半径为200μm的圆形平顶光斑,均方根误差D0.021。当抽样值取2~15时,在普通PC机上运行时间仅为20.05 s,大大节省了优化设计时间(整个优化设计过程往往需要几十次甚是上百次这种运算)。同时利用离子刻蚀技术加工了该折衍混合元件,并进行了实际测试,结果与设计值基本相符,整形效果较好。这种单片的整形元件不仅整形效果好,还有利于与激光器的集成,简化系统的调节。  相似文献   

10.
《Current Applied Physics》2010,10(3):834-837
Here we describe the effect of the incident optical spot size upon the quadrant photodetector on the displacement detection sensitivity of the optical beam deflection method. By varying the size of the beam spot reaching the photodetector and measuring the optical responsivity, we have determined the optical detection sensitivity as a function of the optical spot size on the photodetector. Also, we have calculated the numerical value of the detection sensitivity with the Gaussian optical spot profile and compared with the experimental data. Both experimental and analytic studies show that the optical displacement detection sensitivity increases with the decrease in the width of the Gaussian optical spot. The study presented here will be beneficial in developing the nanomechanical displacement detection techniques based on the beam deflection method with a position-sensitive detector.  相似文献   

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