Figure 2: Bragg ptychography experimental data.
From: Three-dimensional high-resolution quantitative microscopy of extended crystals
(a) Integrated intensity values as a function of the beam translation tx: the two maxima correspond to the two Si lines, which are schematically indicated (grey rectangles). The line is a guide to the eye. (b–g) 2D coherent intensity patterns measured at the Si 220 reflection for different q3 values (indicated on the graphs) and different positions of the focused beam onto the double line crystalline sample. The corresponding tx values are indicated in (a). A splitting of the Bragg peak is observed along q1, emphasized in (e) by the white arrows and the respective peak labels, p1 and p2. The intensity colour scale is logarithmic. The intensity has been multiplied by 6 in (d,e) and by 25 in (f,g), for clarity. The reciprocal space scale is indicated in the figures where |q1|=|q2|=5×107 m−1. (h) Splitting contrast Cs=1−(Imin/Ip) as a function of q3 and tx: Imin is the mean intensity value at the peak splitting minimum and Ip is the mean intensity at the p1 and p2 positions. Therefore, Cs=1 corresponds to a full splitting. In (h), the abrupt change along tx evidences that the Bragg splitting is linked to the sample structure and occurs preferentially at the large line position. The corresponding colour scale is given on the right. The scale is |q3|=2.2×107 m−1.
