Investigation On Resolution Of Self-interference Digital Holography

Self-interference digital holography(SIDH)is a technique that can record holograms of object illuminated with spatial incoherent light.Light emitted from the same point of the object is split into two beams and interfere with each other to form the point-source hologram.All the point-source holograms are superposed incoherently to form the hologram of the extended object.The three dimensional object is retrieved by digital reconstruction.Self-interference digital holography possesses the advantages of non-contact,non-invasive,speckle-noise free and the ability of three dimensional imaging.Self-interference digital holography is great potential to fluorescence microscopy and other incoherent 3D imaging owe to non-dependence on the coherence of the light.As a microscopic imaging system,resolution is an important evaluation parameter and is always pursued.The improvement of transverse imaging resolution and elimination of out-focus information in self-interference digital holography are still need to research further.In this thesis,structured illumination technique is introduced into self-interference digital holography to improve its imaging performance.The factors that influence the imaging performance of uniform illumination self-interference digital holography and structured illumination self-interference digital holography are investigated.The main investigations are summarized as the following:1.The basic principle of self-interference digital holography is illustrated.The factors that influence the imaging performances,especially imaging resolution of self-interference digital holography with uniform illumination are investigated.The recording distance of the hologram,the polarization of the light source and the reconstruction algorithm are changed to find the optimal parameters and algorithm for the system.2.The imaging characteristics of self-interference digital holography are investigated.The transverse and axial resolution of self-interference digital holography are analyzed and compared with the traditional incoherent and coherent imaging system.3.Structured illumination technique is introduced into SIDH to optimize the transverse resolution.The influence of the orientation,the spatial frequency,and the modulation depth of the illumination pattern on resolution improvement are investigated and demonstrated.4.Structured illumination technique is introduced into SIDH to optimize the lateral resolution.The optical sectioning ability of structured illumination imaging is combined to SIDH to eliminate the out-focus information,and the influence of spatial frequency of the illumination pattern and the axial distance of the objects on the optical sectioning strength are investigated and demonstrated.