Study On Resolution Of Incoherent Digital Holography Based On Spatial Light Modulator

Traditional imaging techniques can only record two-dimensional intensity information of objects.As a two-part imaging technique,holography can record the amplitude and phase information of three-dimensional objects simultaneously by using the interference and diffraction principle of light.With the development and maturity of photoelectric sensors and computer technology,incoherent digital holography came into being.Incoherent holography based on self-interference breaks through the stringent restrictions of the traditional holography on the coherence of light sources and overcomes the disadvantage that laser holography requires high stability.It has the advantages of simple structure,fast recording speed,flexible reconstruction and easy matching with existing mature optical systems,and high research value in many fields.This paper studies two kinds of incoherent digital holography: incoherent holography based on Michelson interferometer and incoherent holography based on spatial light modulator.Incoherent holographic camera based on Michelson interferometer is constructed.And the feasibility of generalized phase-shifting interferometry incoherent coaxial holographic system is studied.The basic principle of incoherent digital holography based on spatial light modulator is also analyzed and the imaging characteristics are verified experimentally.On this basis,the helical phase loading mode of spatial light modulator is studied,the feature of edge extraction is verified by microscopic imaging.Finally,the resolution of dual-lens FINCH is discussed in detail.The paper mainly includes the following four aspects;(1)The basic principle of incoherent holography is introduced,and four typical incoherent coaxial recording optical setups are briefly analyzed.Then,the principle of incoherent digital holography based on spatial light modulator is described in detail and the point spread function of this system is obtained.Finally,the imaging characteristics are studied through experiments in three aspects: resolution,two-dimensional and three-dimensional imaging.(2)The incoherent holographic camera based on Michelson interferometer is built,and the point spread function of this system is derived.Three holograms are recorded in sequence.Generalized phase-shifting interferometry instead of the piezo-ceramic actuator is used to eliminate zero-order and twin images.It can not only avoid errors caused by mechanical movement,but also improve the imaging speed.(3)The spiral phase loading mode of spatial light modulator is studied.The accurate mathematical model of the point spread function of the spiral phase modulation system is given.And the edge extraction characteristics were verified by imaging the resolution target and biological samples.(4)The resolution of the incoherent digital holographic system under two determinants of the input and output aperture is studied.When the output aperture is the decisive factor,three factors affecting the resolution of the system are also discussed.The resolution expressions of the system at different recording distance are given.