The One-Ångstrom Microscope (OÅM) project was established at the NCEM to produce images at sub-Ångstrom resolution (O'Keefe, 1993). The project was implemented using a Philips CM300FEG/UT with hardware modifications designed to correct objective lens three-fold astigmatism and extend information transfer to 0.8 Ångstrom (O'Keefe et al., 2001a). A Gatan image filter (GIFTM) was used to bring the image magnification to more than three million times at the CCD camera to provide adequate real-space sampling.
Phase-contrast imaging in the HRTEM produces images with peaks at atom positions by extracting the spatial distribution of the relative phase from the electron wave. Usually, the electron wave is imaged by direct interference of diffracted beams at optimum focus (Scherzer, 1949).