Acquisitions with a detector frame rate of several kHz are currently achieved by employing these cameras. This technology paved the way for momentum-resolved STEM techniques with high samplings in both real and diffraction space, sometimes being referred to as 4D-STEM. The development of ultrafast cameras for transmission electron microscopy (TEM) such as the pnCCD (Müller et al., Reference Müller, Ryll, Ordavo, Ihle, Strüder, Volz, Zweck, Soltau and Rosenauer2012 Ryll et al., Reference Ryll, Simson, Hartmann, Holl, Huth, Ihle, Kondo, Kotula, Liebel, Müller-Caspary, Rosenauer, Sagawa, Schmidt, Soltau and Strüder2016), the Medipix3 chip (Plackett et al., Reference Plackett, Horswell, Gimenez, Marchal, Omar and Tartoni2013), delay-line detectors (Oelsner et al., Reference Oelsner, Schmidt, Schicketanz, Klais, Schönhense, Mergel, Jagutzki and Schmidt-Böcking2001 Müller-Caspary et al., Reference Müller-Caspary, Oelsner and Potapov2015), or the EMPAD (Tate et al., Reference Tate, Purohit, Chamberlain, Nguyen, Hovden, Chang, Deb, Turgut, Heron, Schlom, Ralph, Fuchs, Shanks, Philipp, Muller and Gruner2016) enabled the collection of the full diffraction space up to a flexible cutoff spatial frequency at each scan point in scanning TEM (STEM). The methodology is especially expected to improve contrast- and dose-efficient in situ imaging of weakly scattering specimens, where fast live feedback during the experiment is required. This allows live optimization of instrument as well as specimen parameters during the analysis.
Qualitatively interpretable live results are obtained also if the sample is moved, or magnification is changed during the analysis.
In particular, the single-sideband method is compared with other techniques such as the enhanced ptychographic engine in order to ascertain its capability for structural imaging at increased specimen thickness. Processing of both real experimental and simulated data shows the characteristics of this method when data are processed progressively, as opposed to the usual offline processing of a complete data set. This is combined with live first moment and further virtual STEM detector analysis. A reformulated implementation of single-sideband ptychography enables analysis and display of live detector data streams in 4D scanning transmission electron microscopy (STEM) using the LiberTEM open-source platform.