Zernike phase contrast electron microscopy with a spherically corrected foil lens.
A lens system is proposed that not only provides spherical correction of the objective lens by charges that are induced on a thin foil, in the way proposed in a paper by Otto Scherzer [Optik 56(2), 133-147, 1980], but also provides Zernike phase contrast by means of an appropriate phase shift of the scattered electrons within the foil. This system has the potential to provide strong phase contrast from very low spatial frequencies to frequencies above 1/(100 pm).
Typke
Dieter
D
Life Science Department, Lawrence Berkeley National Laboratory, 1 Cyclotron Road Mailstop Donner, Berkeley, CA 94720, USA.