I am a Grade 11 student and am working on a physics research about Fraunhofer diffraction. I have 2 very basic questions (maybe kind of unprofessional). Hope someone can help. 1.Suppose a beam of coherent, monochromatic, parallel light penetrates an object, and a diffraction pattern forms on the far-field screen. As long as the oversampling ratio satisfies certain conditions, we can use the diffraction pattern to uniquely reconstruct the original object, using phase retrieval program. Is that the case? If so, where I can download a phase retrieval program for Fraunhofer diffraction? I want a program that I can simply input an image of a diffraction pattern, and the program can generate the image of the original object. Is that possible? Or I can program it on MATLAB? 2. What is "oversampling to a diffraction pattern"? And the oversampling ratio? Is it that surround the original object (electron density region) with empty space (no-density region); the area of the empty space measures the extent of oversampling? Or, use different resolution to record the same diffraction pattern? I read some articles found on Google Scholar, but I am a little confused. Thanks for the help!