Shearing Interferometers using diffraction gratings as elements wavefront division

使用衍射光栅作为波前分割元件的剪切干涉仪

基本信息

批准号：
07650056
负责人：
IWATA Koichi
金额：
$ 1.47万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650056/
关键词：
Diffraction Grating Shearing Interferometer Optical CT White Light X-ray Shearing Interferometer

项目摘要

We developed two types of shearing interferometers using diffraction gratings. The one uses a double period diffraction grating. The grating has two periods which are very close to each other. The other interferometer uses four diffraction gratings with the same grating period.In the double period grating system, the difference in diffraction angles produces shearing images. Moreover, since a periodic fringe pattern appears on the shearing image due to the difference in diffraction angles, phase distribution of the interference fringes can be analyzed accurately with a help of Fourier analysis. We made an shearing system with the double period grating for optical CT to measure refractive-index distribution of a phase object. Moreover some discussions were made about errors in refractive-indices reconstructed from the shearing interferometer and the conventional two-beam interferometer. The discussion results an advantage of the sharing type used for the optical CT system.On the other h … More and, we proposed a white light-shearing interferometer using the four diffraction gratings. Sensitivity of a shearing interferometer is proportional to amount of the shear, and the shear amount depends on the diffraction angle which is in proportion to the wavelength of light approximately in case of a small diffraction angle. When the shear image is produced by using a couple of the gratings with a small separation, the phase difference between the interfering light beams does not depend on the wavelength of light. Then the shearing interferometer for a white light source is realized by setting the couple of gratings in front and back of the phase object. We made a simple sharing interferometer with 4 gratings and a halogen light source. The obtained interference fringes pattern did not allow coherent noise and the fringe contrast was close to 0.5 which corresponded to the ideal value. The phase shift technique for a sensitive phase analysis was realized by moving one of the gratings.Moreover, the idea of the four gratings system is applied to X-ray interferometer. We made a X-ray interferometer with four silicon thin-blade which are made from a single domain silicon crystal. Less

我们使用衍射光栅开发了两种类型的剪切干涉仪。一个使用双周期衍射光栅。光栅有两个彼此非常接近的时期。另一个干涉仪使用四个衍射光栅在相同的光栅周期内。在双时期光栅系统中，衍射角差异会产生剪切图像。此外，由于由于衍射角的差异，剪切图像上出现了周期性的条纹模式，因此可以在傅立叶分析的帮助下准确地分析干扰条纹的相位分布。我们制作了一个剪切系统，用于光学CT的双周期光栅，以测量相位对象的折射率分布。此外，关于从剪切干涉仪和常规的两光束干涉仪中重建的折射率错误的错误进行了一些讨论。讨论导致了用于光学CT系统的共享类型的优势。在另一个H上……更多，我们提出了使用四个衍射光栅提出的白色灯罩干涉仪。剪切干涉仪的敏感性与剪切量成正比，剪切量取决于在小衍射角大约与光波长成比例的衍射角。当通过使用几个光栅分离较小的光栅产生剪切图像时，干扰光束之间的相位差不取决于光的波长。然后，通过将几个光栅设置在相位对象的前后，可以实现白光源的剪切干涉仪。我们制作了一个简单的共享干涉仪，使用4个光栅和一个卤素灯源。获得的干扰条纹模式不允许连贯的噪声，边缘对比度接近0.5，与理想值相对应。通过移动一个光栅来实现敏感相分析的相移技术。此外，四个光栅系统的想法应用于X射线干涉仪。我们用四个由单个域硅晶体制成的X射线干涉仪与四个硅薄叶片制成。较少的