Comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method

Abstract

This work reports an experimental comparative study between the two most frequently used numerical reconstruction methods in digital holography; i.e. angular spectrum method (ASM) and Fresnel diffraction method (FDM). As distance between object plane and recording plane is an important factor for selection of a reconstruction method in digital holography, thus here comparison between the two methods is made on the basis of variable distance between object and recording plane (i.e. CMOS image sensor). The ASM is also known as double Fourier transform method as it involves inverse Fourier transform of Fourier transformed incident field and transfer function of the system. While, FDM involves numerical reconstruction by calculating diffracted field using Fresnel diffraction formula. In present work, Angular spectrum and Fresnel diffraction methods are applied for numerical reconstruction of digital holograms of a transparent object, recorded at different distances from CMOS sensor. Experimental results are presented and distance constraints for both methods are discussed in different experimental situations.