The Uniqueness of Phase Retrieval from Intensity Measurements

摘要

Several aspects of the question of the determination of the phase of a wavefield from the knowledge of its intensity in the aperture plane and focal plane of a thin lens are investigated. The role of diffraction from the lens aperture is studied. It is shown that for an astigmatic Gaussian beam this method of phase retrieval is highly nonunique if the beamwidth in the aperture plane is much smaller than the radius of the aperture. For several test cases, it is shown that if the beamwidth is not small compared to the radius of the aperture the above-mentioned nonuniqueness is removed (except for the well-known twin solution ambiguity). The twin solution is discussed and a method for eliminating it is proposed. (Author)