Talbot Effect Of Grating And Its Application In Wave-front Sensing

When a grating is illuminated a parallel light, its self-images appear at somecertain distances behind grating. This is the so-called Talbot effect. As an significantoptical phenomenon of grating diffraction, Talbot effect has been widely applied inmany aspects, such as the array illumination, the laser array phase locking,information coding, etc. Moreover, the related researches have extended from theclassical optics into other research fields such as atomic optics, Bose-Einsteincondensation, optical waveguide, quantum optics and nonlinear optics. Talbot effectof grating has become an important technique in electron microscopy and X-raydiffraction imaging. Therefore, it has very important scientific significance andapplication value to carry out the research on Talbot effect of grating for promotingthe applications of Talbot effect and the cross development of different disciplines.And that is the reason why it becomes a very active research topic in the field ofoptics.Usually, the grating appears in the related theoretical and applied research as anideal periodic diffraction screen. However, in the actual production of the gratingespecially with large size, it is difficult to achieve a uniform grating everywhere.Moreover, because of grating material, grating fixedness, grating gravity and othervarious factors, it is difficult to guarantee that grating is perfectly flat in the practicalapplication of grating. The un-flatness of the actual grating can cause the deviation ofexperiment results from the theoretical ones. Therefore, it has practical significance tostudy Talbot effect of curved grating for the correct evaluation of the flatness ofgrating. In addition, with comparison to the ideal Talbot image of grating obtainedunder illumination of parallel light, Talbot image of grating illuminated by thenon-perfect parallel light must appear the distortion. This is the reason that Talboteffect can be used in the wave-front sensing.This paper focuses on the studies about Talbot effect of the grating illuminatedobliquely with the incident wave, Talbot effect of curved grating and the applicationof Talbot effect in extracting the information of moving objects, and the specific content is divided into five chapters. The first chapter introduces the diffractionof grating and Talbot effect of the grating. The second chapter analyzes Talbot effectof grating with parallel light oblique incidence and spherical wave incidence. Theevolution rule of Talbot image with incident conditions provides a theoretical basis forthe extraction of phase information of light source on basis of Talbot image of grating.Talbot effect of curved effect is studied in the third chapter. The evolution mechanismof Talbot imaging of the curved gratings is presented by choosing parabolic cylinder,cylinder and elliptic cylindrical as examples. And the distortion caused by the curve ofgrating is verified by experimental measurements. The fourth chapter studies themodulation diffraction of grating by inserting the moving phase object and presentsthe extraction method of the information of the moving phase object based on Talboteffect. The swimming fish and the moving broken glass are chosen as examples toshow again the application of Talbot effect in the wave-front sensing. Finally, theconclusion this paper and the prospect of following work are given.