Study On Common-path And Off-axis Polarization Digital Holography And Its Applications

Digital holography(DH),due to its superior ability in quantitatively measuring the complex amplitude distributions of optical fields,has drawn much attention in recent years and been widely applied in many significant fields.Common-path and off-axis digital holography(CODH)is one of off-axis holographic techniques developed in recent years,in which both the imaging and the reference beams for off-axis interferometric recording propagate nearly through the same optical path and the same imaging lenses.Compared with the non-common path DHs based on Mach-Zehnder or Michelson interferometers,CODHs are more stable,relatively insensitive to mechanical vibrations and air fluctuations,and require fewer optical elements.Because of these advanages above,CODHs have been widely used in digital holography microscopy,quantitative phase measurements,polarization holographic measurements and other fields.In this dissertation,theoretical and experimental research on common-path and off-axis polarization DHs have been carried out.The works and achieved results are summarized below:1.A literature review of the research background and development status of holographic technology,especially digital holography,is given.The method of eliminating zero-order images and twin images in reconstruction images,the reconstruction algorithm of DHs and the method used to improve the resolution of DHs are briefly introduced.We show the advantages and problems of common-path and off-axis DHs,and the improvement based on the concept of space-division multiplexing in recent years.We have focused on the application of commonpath off-axis polarization digital holography in the polarization measurement in recent years.2.The foundation of scalar diffraction theory and polarization are introduced briefly,including scalar diffraction theory and commonly used integral formulas derived from scalar diffraction theory.We give a brief introduction of some diffraction integral formulas,the principle of recording and reconstruction in holography,the recording conditions of holography with off-axis configuration and two reconstruction algorithms commonly used: Fresnel transform method and convolution method.The relationship between resolution of reconstructed image and the wavelength and distance in reconstruction using the two methods above is compared.The basic theory of polarization is briefly introduced,including the representation of polarization optical field using the Stocks vector and the Jones vector,and the representation of polarization optical elements using the Jones matrix.3.The numerical simulation method for calculating a diffraction light field involved in the reconstruction of DHs is researched.An improved transfer function sampling algorithm is proposed to overcome the disadvantage of existing transfer function method.Using the new method,the diffraction light field at any distance can be accurately calculated,overcoming the difficulties of the existed algorithm in calculating the diffraction field with diffraction distances larger than the feature distance.The new method is called amended transfer function(ATF)sampling algorithm to distinguish with the existing transfer function method.The diffraction fields at different distances are calculated based on the amended and existing transfer function sampling algorithm respectively.The results obtained from the two algorithms above are compared with the result calculated by theory to verify the accuracy and superiority of the new method.The numerical simulation algorithm used to calculate the diffraction field with circular symmetric based on fast Hankel transform is given.The result obtained by the algorithm above is shown in the dissertation.Finally,the diffraction field of the Fresnel zone plate with circular focusing manner and line focusing manner designed by the wave vector integral method is calculated respectively with the ATF sampling algorithm based on fast Hankel transform.4.A double-channel common-path and off-axis polarization holography imaging method based on orthogonal grating shearing interference is proposed.Using this method,one can record and reconstruct the complex amplitude of the two orthogonal polarized components of the object beam in real time.Furtherly,the polarization state of the tested optical field and birefringence characteristics of the sample can be measured.We show the relationship between the recording characteristics and system parameters of a one-arm lateral shearing interferometers based on a grating theoretically.Then the recording and measuring principle is explained with the schematic diagram of the double-channel common-path and off-axis polarization holography system based on orthogonal grating shearing interference.And then,a simulation based on Matlab is carried on to verify the theoretical analysis.The system is built in laboratory to measure the polarization state of the light field passing through the birefringence sample.5.A method used to measure the complex amplitude modulation characteristics of Liquid Crystal Spatial Light Modulators(LCSLM)in experiment is proposed.We analyze and deduce the Jones matrix of LCSLM.The method used to measure the four Jones matrix parameters of the LCSLM by the double-channel common-path and off-axis polarization holography imaging system and the method to eliminate the background noise are given through a theoretical analysis.The two-dimensional distribution of Jones matrix for TN-LCSLM in 0-255 gray is measured experimentally,and the variation curve of amplitude and phase of Jones matrix parameters with gray is shown in the dissertation.Some experiment results to verify the accuracy of the Jones matrix parameters are given furtherly.