Study of the recording condition about the digital hologram recorded with spherical reference wave

Based on Fresnel diffraction formula,the spatial spectrum distribution of hologram recorded with spherical reference wave is analyzed.By use of the sampling theorem and the condition of spectrum separation,the generic recording condition of the digital hologram of the spherical reference wave is deduced,and the minimum recording distances and the offsets of the reference wave about some practical and special recording configuration are obtained The deducing method in this paper is more simple and rigorous than others.The computer simulation shows that the results are correct.In addition,the Fresnel approximation is a very good reconstructing method;the very high ultimate resolution of the reconstructed image can be obtained with in-line lensless Fourier transform digital holography.