THE THEORETICAL BASIS OF ELECTRON-EMISSION HOLOGRAPHY AND TOMOGRAPHY

We investigate the theoretical foundation of electron emission hologra phy for surface structure analysis by using the Lippmann-Schwinger int egral equation to examine the reconstruction integral for electron hol ography. We elucidate the physical content of single-energy electron e mission holograms and demonstrate the non-uniqueness of the holographi c image. We examine the physical meaning of images obtained by the coh erent superposition of multi-energy holograms in the weak scattering l imit. We show that the coherent superposition of holographic image fie lds is an electron tomogram of the scattering potential. This establis hes close connection between recently proposed methods for image impro vement in electron holography and conventional image reconstruction sc hemes by computerized tomography. An optimal reconstruction algorithm, which retrieves a 3D image of the scattering potential in the weak sc attering limit, is proposed.