A Study Of Reconstruction Of Optical Wave Fields And Inverse Operation Of Diffraction

The diffraction of light is an important optical phenomena, it has the important value in the practical application, such as optical interferometry, the recording and reconstruction of hologram, as well as optical system imagery analysis and so on. We only can obtain the intensity distribution of diffracted optical wave fields by the ordinary photography, phases cannot be recorded and calculated. But the phases often carry much useful information in optical interferometry, therefore it is important to research the reconstruction of phase distribution of diffracted optical wave fields. On the other hand, we generally are interested in the optical wave fields nearby the tested object, instead of distribution of diffracted optical wave fields. If we can obtain the optical wave fields nearby the tested object from diffracted optical wave fields, it enables the problem to be solved. This is the inverse operation of diffraction.The developments of digital holography are based on optical holography; digital holography is a union of photo electricity sensor technology, digital image processing, Fourier optics, digital computer technology and traditional holography theory. Digital holography implements the numeralization of recording and reconstruction of hologram, established the new fields of application for holography. With the aid of the digital holography, we may realize the inverse operation of diffraction and reconstruction of optical wave fields.In the second chapter of this dissertation, we analyzed the mathematic representation of complex amplitude of optical wave fields, introduced Kirchhoff's scalar diffraction theory and its Fresnel approximate expression, introduced emphatically fundament of digital holography. The reconstruction methods of hologram consisted of the reconstruction of a single digital hologram and the reconstruction of digital hologram based on phase-shifting technology. The main reconstruction methods for a single hologram are Fourier integral method and convolution algorithm reconstruction. We analyzed and compared them by theory and experiment: we used the methods of digital image processing in the course of numerical reconstruction, such as digital filter method and mean value method.In the third chapter of this dissertation, we analyzed, deduced the correlative formula which implement inverse operation of diffraction by Fourier integral and convolution algorithm. We reconstructed the complex amplitude of optical wave fields on the diffraction plane by computer simulation, simultaneity validated it by experiment. The result of experiment is consistent with that of computer simulation. That proved the formula of inverse operation of diffraction is correct. Finally, we reconstructed the optical wave fields on random plane that perpendicular to optical axis in the Fresnel diffraction region of hologram by computer simulation and experiment. We know the result of computer simulation accord with that of experiment; this proved it is feasible that reconstructed the optical wave fields by digital holography; carried out inverse operation of diffraction; implemented the reconstruction of the optical wave fields on random plane in the Fresnel diffraction region of hologram.