Abstract
A method using a shadow image of fine particles, proposed for the stigmation and the measurement of spherical aberration of the probe-forming lens, was further developed for the accurate measurement of spherical aberration and of non-rotationally symmetrical axial aberrations. From the radii of the rings of infinite magnification in a pair of shadow images, the coefficient of two- or three-fold astigmatism or axial coma can be measured together with the spherical aberration coefficient. A theoretical evaluation and an experiment carried out with a probe-forming lens of 1.5 nm resolution showed that the error of measurement is within several percent for the spherical aberration coefficient and is less than 30 nm for the coefficient of two-fold astigmatism. The three-fold astigmatism remaining after the correction of spherical aberration was also measured and was found to be of considerable importance in limiting the performance of the spherically corrected lens.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
