Patent ID: 7973289

Claim:
A method for producing image contrast by phase shifting in electron optics, the method comprising the steps of: a) producing an anamorphic image of axial rays from an intermediate image of the axial rays using first quadrupole fields disposed upstream of the anamorphic image with simultaneous passage through zero of field beams in at least one diffraction image plane; b) effecting a relative phase shift between a region around the electron beam of zeroth order of diffraction and electron beams of higher orders of diffraction using a magnetic or electric field; c) correcting the anamorphic image using at least one downstream second quadrupole field; and d) appropriately selecting a magnification M of the intermediate image such that at least one of the axial rays enters the first quadrupole fields at a slope 1/M such that a length of the anamorphic image is achieved at which aberrations caused are still within a tolerable range, wherein the first and the second quadrupole fields have an extent in a direction of an optical axis which is at least twice as large as focal lengths thereof.