Research Of Vector Diffraction Calculation

The diffraction phenomenon plays an important role in optics,which has been attracting more and more attentions of researchers attrabuting to its complex nature.From the theory of fluctuation of light put forward by Huygens in the 17th century,the theory of diffraction has been constantly revised and improved through the efforts of researchers.Although the scalar diffraction can accurately solve the calculation diffraction problem,but the scalar diffraction theory is not suitable for small-scale and large-angle diffraction,so we need to use the vector diffraction theory for solving the calculation more strict.On the basis of scalar and vector diffraction theory and Huygens' theory,a method of calculating vector diffraction by computer is proposed.This method can test the effect of different inclination factors of each diffraction theory on diffraction calculation results,and the diffraction of different shapes of diffraction apertures was calculated by this method.The specific content of this thesis is as follows:(1)The continuous integral operation in the Huygens-Fresnel principle can be insteaed by the discrete numerical summation based on the understanding of the Huygens principle and the vector properties of light,through the method can ues the computing power of the computer to replace the integral process of the diffraction calculation,so the diffraction process in Huygens' principle can be reproduced on the computer.At the same time,we have been calculated two typical cases of the diffraction,the rectangular aperture and the circular aperture,which proves the correctness of the vector diffraction method proposed in this thesis by compared the calculated results with the theoretical ones.(2)Base on the calculation results of the inclination factor in Kirchhoffs theory which is the most widely used,we have been explored the influence of other types of inclination factor through compared with the calculation results.When the diffraction angle is small,the different inclination factors have little effect on the calculation results as shown the calculations.When the diffraction angles exceed a certain value,the different inclination factors have a greater influence on the diffraction results even exceeding 50%.(3)The shape and the incident light source of the diffraction aperture are further calculated and analyzed through using the computational flexibility of the computer.By comparing the calculation result with the known conclusion and the published result,it is proved that the method is more flexible in the setting of the diffraction holes and the setting of the incident light source,which provides more possibilities for the application of the diffraction method in practical calculation.