A Novel Three-Step Lensless Coherent Diffraction Imaging Method

Abstract

The invention relates to a novel three-step lens-free coherent diffractive imaging method. The method is characterized in that laser beams subjected to collimation and beam expansion are used to illuminate a to-be-measured sample, and recording a diffraction pattern when the front end of CCD has no optical parallels, a diffraction pattern when the front end of the CCD has one optical parallel and a diffraction pattern when the front end of the CCD has two optical parallels; using an algorithm combining wave filtering and coherent diffractive imaging to process the three diffraction patterns, and rebuilding the complex amplitude image of the to-be-measured sample. The novel three-step lens-free coherent diffractive imaging method has the advantages that the bottleneck problem that a traditional coherent diffractive imaging method needs to move the CCD or the to-be-measured sample for multiple times is solved effectively, the problems of random errors during moving and experiment operability are solved at the same time, the method is simple and fast in experiment operation and high in operability, the coherent diffractive imaging algorithm is effectively combined with wave filtering, and convergence rate and a sample recovery effect are increased.

Description

technical field [0001] The invention relates to the technical field of optical diffraction imaging, in particular to a novel three-step lensless coherent diffraction imaging method. Background technique [0002] There have been many developments in lensless coherent diffraction imaging in recent years, and the method generally uses an iterative algorithm. The complex amplitude information of the object can be reproduced from the diffraction intensity pattern of the object without reference light. It has a very wide range of wavelengths and has been widely used in lensless coherent diffraction imaging of X-rays and electron beams. See (Opt.Lett.31, 3095-3097 (2006); J.Opt.Soc.Am.A25, 416-422 (2008); Nat.Phys., 4, 394-398 (2008); Appl.Opt. 21, 2758-2769 (1982); J.Opt.Soc.Am.A 23, 1179-1200 (2006)) After the sample is irradiated by a beam of coherent light, the diffraction pattern generated by the sample is received on the CCD. In order to obtain more accurate amplitude and p...

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Problems solved by technology

See (Opt.Lett.30 (8), 833-5 (2005)) but on these technical schemes, they have following technical defect: need to obtain the diffraction surface of a plurality of different distances, take moving sample or CCD in the implementation process This method needs to change the position of the sample or CCD repeatedly, which requires a lot of repetitive work. At the same time, it introduces random errors that directly affect the experimental results. The accuracy of the obtained sampling pattern is not high, and requires Oversampling, long experimental operation cycle and weak operability, poor timeliness of imaging

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