Abstract: A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

Abstract: An optical phase plate system and method for enhancing phase contrast in electron beam imaging includes a transmission electron microscope (TEM) having a back focal plane; an optical cavity having a high internal surface reflectance, the center of the optical cavity located at the back focal plane of the TEM, the optical cavity having first and second ports arranged oppositely along a symmetrical axis of the optical cavity to admit an electron beam provided by the TEM through the first port to pass through and focus at the center of the optical cavity, and to exit through the second port, and wherein the optical cavity further has an optical port on an axis transverse to and intersecting the electron beam axis to admit a laser beam; a laser coupled to the optical cavity to provide a laser beam of a selected wavelength to enter the optical cavity through the optical port, wherein the laser beam is multiply reflected from the high internal surface reflectance to provide a high intensity standing wave optical ph

Abstract: A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected.