Topic
Contrast transfer function
About: Contrast transfer function is a research topic. Over the lifetime, 934 publications have been published within this topic receiving 26533 citations.
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11 May 2001TL;DR: A genetic learning algorithm is applied in conjunction with third harmonic generation to determine the appropriate shape of the deformable mirror to correct for aberrations in longitudinal depth scanning in a confocal microscope.
Abstract: Summary form only given. In normal operation with a dry or oil immersion microscope objective there is an index mismatch with a water-based biological sample. This index mismatch causes a depth dependant spherical aberration that severely limits the range that a sample can be imaged along the optical axis. We have previously demonstrated the use of a membrane deformable mirror to correct for off-axis aberrations in a confocal microscopy system. In this study we apply a genetic learning algorithm in conjunction with third harmonic generation to determine the appropriate shape of the deformable mirror to correct for aberrations in longitudinal depth scanning in a confocal microscope.
01 Jan 1989
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17 Jun 2007
TL;DR: In this paper, a two-frequency linear polarized photon-pairs (LPPPs) laser beam is produced, which not only reduces the spherical aberration but also decreases scattering effect in specimen at the same time.
Abstract: Refractive-index mismatch in conventional confocal microscopy produces severe degradation on axial resolution of sectioning image because the spherical aberration is generated in specimen. In this study, we propose a polarized photon-pairs confocal laser scanning microscope (PCLSM) in which a two-frequency linear polarized photon-pairs (LPPPs) laser beam is produced. The common-path propagation of LPPPs integrated with optical heterodyne technique not only can reduce the spherical aberration but also decreases scattering effect in specimen at same time. Therefore, the better axial and lateral resolutions of the sectioning image are produced simultaneously. In the experiment, a verification and comparison between PCLSM and conventional confocal laser scanning microscope (CLSM) on the ability of cancellation of spherical aberration induced by cover glass are demonstrated experimentally. Finally, the ability of PCLSM which can decrease the spherical aberration based on the common-path propagation of LPPPs associated with polarization gating, spatial coherence gating and spatial filtering gating is discussed.
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17 Jun 2006
TL;DR: In this paper, the authors report progress in the construction of a new aberration-corrected photoemission electron microscope, which is a hyperbolic electron mirror, correcting for chromatic and spherical aberration.
Abstract: We report recent progress in the construction of a new aberration-corrected photoemission electron microscope. The correction element in this instrument is a hyperbolic electron mirror, correcting for chromatic and spherical aberration. We present results from a numerical simulation combining a trajectory and wave-optical analysis, and we discuss the calculation of the modulation transfer function in this approach. First images on nano-structured metal and semiconductor surfaces have been obtained with the new instrument and are also presented.
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26 Jul 1993TL;DR: In this article, the 3D coherent transfer function (CTF) of a confocal microscope was analyzed in terms of the concept of the 3-dimensional coherent transfer functions (CTFs) and the effects of the annular pupil function and spherical aberration on the CTF were investigated.
Abstract: We report on the analysis of the three-dimensional (3-D) image formation in a confocal microscope in terms of the concept of the 3-D coherent transfer function (CTF). The effects of the annular pupil function and spherical aberration on the 3-D CTF are investigated. The 3-D CTF for a new fibre-optical confocal system consisting of optical fibres for illumination and collection is described. We also discuss the significance of the 3-D CTF and, in particular, the relationship between the 3-D CTF and 2-D and 1-D imaging.