RECONSTRUCTION OF ELECTRON OFF-AXIS HOLOGRAMS - A NEW AND FAST ALTERNATIVE METHOD

In a conventional electron microscope the image intensity, i.e. the su m of the modulus square of the elastic image wavefunction and the inte nsity of the inelastically scattered electrons is recorded. The inform ation of the phase of the elastic image wavefunction is lost. From an image-plane off-axis hologram, however, the image phase and image ampl itude, i.e. the phase and the modulus (''amplitude'') of the elastic i mage wavefunction, may be reconstructed using fast Fourier algorithms. However, the conventional reconstruction of holograms requires a larg e amount of processing time. A new alternative reconstruction procedur e is presented which avoids the fast Fourier algorithm. It allows an e xtremely fast and convenient determination of the image phase and imag e intensity. The display of image phase and intensity at TV rate appea rs to be possible, but is limited so far by the read-out time of the C CD camera.