Deterministic electron ptychography at atomic resolution

We present a fast deterministic approach to the ptychographic reconstruction of the transmission function of a specimen at atomic resolution. The method is demonstrated using a data set obtained from a cerium dioxide nanoparticle using an aberration-corrected electron microscope and is compared to established approaches to ptychography. The method is based on the solution of an overdetermined set of linear equations, and is computationally efficient and robust to measurement noise. The set of linear equations is efficiently solved using the conjugate gradient least squares method implemented using fast Fourier transforms.