Phase retrieval of electron rocking curves using total variation and total squared variation regularizations

In this study, a new method for the phase retrieval of electron rocking curves observed using convergent-beam electron diffraction, which is applicable to the determination of three-dimensional lattice displacement fields along the beam direction, is proposed. Total variation and total squared variation regularizations are introduced for phase retrieval to suppress overfitting to noise or background signals in the rocking curves and to reproduce the sparse characteristics of displacement fields, which exist only near lattice defects. The results show that the proposed algorithm is effective for rocking curves modulated by the dynamical effect of electron diffraction. The accuracy of phase reconstruction using the proposed method is also discussed. Phase retrieval of the experimental rocking curves obtained from a stacking fault in stainless steel is demonstrated.