Design of a hybrid double-sideband/single-sideband (schlieren) objective aperture suitable for electron microscopy

► New objective-aperture design is proposed for imaging weak-phase objects. ► Design produces single-sideband contrast at low spatial frequencies. ► Design also retains Scherzer-defocus phase contrast at higher resolution. ► Proof-of-concept results are presented for microfabricated apertures. ► Charging of such apertures during use remains an experimental challenge.