Research Of Sub-Diffraction In Optical Diffraction Field

The term, so-called Sub-diffraction, is a description of the special method used in the research of optics diffraction. The research is based on the Huygens's principle and the superposition principle. The points on the wave front, according to Huygens's principle, can serve as new wave sources to emit the spherical wavelets, which constitute the next wave front.In this thesis, the regularity that the filed strength of the filed point in the diffraction filed changes with time will be analyzed in detail. A simulation experiment based on computer technology has been carried out, and the result given by the simulation experiment confirms that the filed strength of the filed point in the diffraction filed, a simple harmonic vibration source, changes with time in sine law. That is, the construction about wavelet in Huygens's principle has been tested theoretically and experimentally to be rational and correct.Further more, the filed points of the screen in the diffraction filed will serve as the wavelet sources and all the wavelets from the wavelet sources will superpose together on the next screen. That process will be called in this thesis as a sub-diffraction which is divided into the strict wavelet source sub-diffraction and non-strict wavelet source sub-diffraction according to the different approaches in the research. The analysis of two sub-diffraction processes indicates that the sub-diffraction gives the same filed strength distribution, compared with the direct diffraction, which has been confirmed by the subsequent simulation experiment.Otherwise, in this thesis another valuable outcome will be presented, that is, the information of the hole if the data is processed properly will be showed on the second screen in the research process of the non-strict wavelet source diffraction.