Fig. 13

Extrapolation of the phase resolution. The achievable real phase resolution depends on the required spatial resolution according to which the reconstruction is performed. This relation, as experimentally determined for the acquired holograms, is shown in (a). In the present work, the resolution range marked by the black circle in (a) was used. Simulations were performed in regard to this range, illustrating under which conditions (potential variation, specimen thickness, fringe contrast, or acquisition time) a potential variation is detectable by off-axis holograms with an SNR of 3. Two examples are shown for fluctuations of b 1V and c 100 mV, for different thickness of the inhomogeneities (20–200 nm). The simulations are based on an extrapolation of the present conditions under which the holograms were acquired, i.e., a fringe contrast of \(\sim\)13.8 %, the acquisition time of 5 s and the achieved phase resolution of 0.2 rad. These conditions are marked by a red dot in (b) and (c)