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Showing papers on "Contrast transfer function published in 1982"


Journal ArticleDOI
TL;DR: Analytical expressions that give the position of the diffraction focus, peak intensity, and tolerance conditions for uniform and Gaussian beams in an optical system with primary spherical aberration are obtained on the basis of diffraction theory.
Abstract: In many laser applications it is important to analyze the effect of the aberrations of optical systems which are employed to focus off-axis beams that only partially fill the system aperture. In this paper analytical expressions that give the position of the diffraction focus, peak intensity, and tolerance conditions for uniform and Gaussian beams in an optical system with primary spherical aberration are obtained on the basis of diffraction theory. The results presented are very useful for designing focusing systems for use with laser beams.

17 citations


Book ChapterDOI
TL;DR: In this paper, the advancement in the development in methods of electron microscopy is examined, and the empirical studies of the radiation damage effect under electron microscope conditions are also presented, where it is shown that radiation damage is the fundamental limitation in the overall effort to obtain high-resolution images of biological materials.
Abstract: Publisher Summary This chapter examines the advancement in the developments in methods of electron microscopy. The electron microscope is an optical instrument, which permits the direct visual observation of structure at very high resolution. High-resolution images can only be obtained, however, if the specimen materials are prepared in a suitable form. Among the requirements that must be met, is that the specimens should be very thin, that they can be placed into a vacuum of 10−6. Electron microscopes have traditionally been designed to be operated at energy of 100 keV. It is the spherical and chromatic aberration of the objective lens and not the electron wavelength, which limit the resolution, because the electron optical lens aberrations cannot be corrected in the same way as, is possible in light optical systems. Radiation damage is the fundamental limitation in the overall effort to obtain high-resolution images of biological materials. The empirical studies of the radiation damage effect under electron microscope conditions are also presented.

5 citations




Journal ArticleDOI
TL;DR: An analysis of spherical aberration in on-axis and offset unstable laser resonators is presented and closed-form analytic expressions of the associated Strehl ratio as a function of cavity dimensions and magnification are derived.
Abstract: An analysis of spherical aberration in on-axis and offset unstable laser resonators is presented. Closed-form analytic expressions of the associated Strehl ratio as a function of cavity dimensions and magnification are derived, and effects of simple phase corrections in the optical system are assumed.