Reconstruction Method for Phase-Shifting Electron Holography Fitted with Fresnel Diffraction Affected Fringes

Abstract

Phase shifting electron holography is a transmission electron microscope technique that a number of holograms with different initial phases are acquired by changing the angle of the incident electron beam, and the intensity variation at a certain point on the holograms is fitted by sinusoidal curve to retrieve the object wave passing through a specimen. In reality, however, Fresnel fringes caused by the electrostatic biprism modulates the electron wave, limits the fitting accuracy and results in phase errors in phase reconstruction. In this study, we suggest a modified phase reconstruction method for phase shifting electron holography. The intensity variations at a certain point on each hologram are fitted not by sinusoidal curve, but by Fresnel diffraction affected curve to retrieve the object wave. This would provide better fitting accuracy, and has a potential to improve the precision of phase shifting electron holography. Simulations demonstrated the improvements of this method comparing with conventional phase shifting holography method.