Study On Fresnel Incoherent Correlation Holography With Large Field-of-view And Real-time Dynamic Recording

Fresnel incoherent correlation holography(FINCH)technology is a method of recording Fresnel holography using spatial incoherent light illumination.The most significant advantage of FINCH technology is that it records 3D objects quickly,and a large number of research results show that the system has a high imaging resolution.At present,FINCH has become an important tool in optical imaging,especially in biological microscope imaging.However,the recording field-of-view of FINCH system is much smaller than that of traditional optical holographic system because of the limitation of pixel number and size of spatial light modulator(SLM)and image sensor(CCD,CMOS).Therefore,it is particularly important to expand the recorded field-of-view of FINCH technology,which weakens the adaptability of FINCH technology in the face of a large range.In this paper,the wide field-of-view mask is designed based on the recording principle of FINCH system and the theoretical analysis of SLM effective aperture.And the field-of-view of FINCH system was effectively enlarged through building experimental light path and using simple computer control.In addition,there are required at least recording holograms two times because the optical path set of FINCH is configured as a coaxial interference system.Then,the phase-shifting method is used to remove the zero-order term and the twin images to obtain the final complex hologram.So,this method is not suitable for observing living cells or recording fast-moving objects.Therefore,the single-shot technology based on FINCH system came into being.This paper focuses on the research of real-time dynamic recording method based on FINCH system,and analyzes the principle of a single exposure recording method based on SLM with the characteristics of regionally loaded phase masks in detail.The reliability of the method is verified by numerical simulations and experiments.In order to further promote the development and application of incoherent digital holography(IDH)in real-time microscopic imaging,the main contents of this paper are as follows:(1)This paper briefly introduces the introduction and development ofincoherent digital holography,the development of FINCH system and the research status at home and abroad.We also analyzed the research background of the FINCH system in large-field and single-shot imaging.(2)The recording and reproducing process of FINCH system is theoretically derived.On the one hand,firstly,we gives the eigenfunction equation of SLM.Then,the point spread function(PSF)of the system is calculated and the expression of the hologram is given.Finally,several diffraction methods for reconstruction of hologram are discussed,and the the reconstruction process of angle spectrum diffraction algorithm is mainly introduced.On the other hand,the optical path of FINCH system,the parameters and functions of each optical element are introduced.(3)The factors which affect the recording field-of-view of FINCH system are analyzed and the effective field-of-view angle of SLM is given.We design large field-of-view masks at the center of the optical axis of different double lenses,and use the computer to control the mask on SLM,so the recording aperture of SLM is effectively expanded.In addition,we record the holograms under different field-of-view through experiments,and each hologram is reconstructed and blended into a large field-of-view image.So,the high resolution large field imaging of FINCH system is completed.(4)The method of single shot of three optical axes based on FINCH system is introduced.The differences and advantages between the proposed method and the parallel phase-shifting method are compared.The real-time imaging method studied in this paper mainly uses the loading method of SLM's divisible region.The SLM was divided into three intervals and loaded the double-lens masks with different phase-shifting angles respectively.A composite hologram containing three hub-holograms of different phase is obtained by only a single shot.Therefore,a clear reconstructed image is obtained after the data processing by three-step phase-shifting linear superposition and angular spectrum diffraction method.The single shot holographic recording process is simulated on the computer,and the experimental optical path is designed and built to record the dynamic video of dice which is placed on a rotating table.The experimental results fully prove that the single exposure method has the ability of real-time dynamic imaging.