نتایج جستجو برای: spherical aberration

تعداد نتایج: 53854  

Journal: :Journal of microscopy 2002
L Sherman J Y Ye O Albert T B Norris

We demonstrate adaptive aberration correction for depth-induced spherical aberration in a multiphoton scanning microscope with a micromachined deformable mirror. Correction was made using a genetic learning algorithm with two-photon fluorescence intensity feedback to determine the desired shape for an adaptive mirror. For a 40x/0.6 NA long working distance objective, the axial scanning range wa...

Journal: :Journal of refractive surgery 2004
Lourdes Llorente Sergio Barbero Jesus Merayo Susana Marcos

PURPOSE To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality. METHODS Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 +/- 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measur...

2014
B. L. Rickman W. A. Schroeder

Scherzer’s theorem states that all static round magnetic and electro-static electron lenses possess positive spherical aberration [1]. As a result, in recent years, much effort has been invested in techniques to correct for the spatial aberrations (Cs) of objective lenses in high resolution electron microscopy. For pulsed electron sources, such as those required for ultrafast transmission elect...

Journal: :Investigative ophthalmology & visual science 2017
Juan Tabernero Lucía Hervella Antonio Benito Lucía Colodro-Conde Juan R Ordoñana Marcos Ruiz-Sanchez José María Marín Pablo Artal

Purpose The human eye has typically more optical aberrations than conventional artificial optical systems. While the lower order modes (defocus and astigmatism) are well studied, our purpose is to explore the influence of genes versus the environment on the higher order aberrations of the optical components of the eye. Methods We have performed a classical twin study in a sample from the Regi...

Journal: :Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2004
Chun-Lin Jia Markus Lentzen Knut Urban

A novel imaging mode for high-resolution transmission electron microscopy is described. It is based on the adjustment of a negative value of the spherical aberration C S of the objective lens of a transmission electron microscope equipped with a multipole aberration corrector system. Negative spherical aberration applied together with an overfocus yields high-resolution images with bright-atom ...

Journal: :Optics letters 2012
Huanqing Guo Hamid R Fallah Chris Dainty Alexander V Goncharov

We present a new method for subjectively evaluating intraocular lenses (IOLs) without implantation surgery. To illustrate the method, three types of single-piece IOL (equispherical monofocal, rotational symmetric aspheric monofocal, and diffractive bifocal) were assembled into a model eye and evaluated using an ocular adaptive optics system by a single subject. To separate the spherical aberrat...

Journal: :Optics express 2016
L Huang P S Salter F Payne M J Booth

The depth dependent spherical aberration is investigated for ultrafast laser written waveguides fabricated in a transverse writing geometry using the slit beam shaping technique in the low pulse repetition rate regime. The axial elongation of the focus caused by the aberration leads to a distortion of the refractive index change, and waveguides designed as single mode become multimode. We theor...

Journal: :Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2014
Binghui Ge Yumei Wang Yunjie Chang Yuan Yao

High precision determination of atomic position is necessary for quantitative electron microscopy so that small width of peaks, which represent atoms in structural images, adequate resolution, and sufficiently strong image contrast are needed. The width of peak is usually determined by the point spread (PS) of instruments, but the PS of objects should also be taken into consideration in aberrat...

2010
Mohammad-Reza Jafarinasab Sepehr Feizi Ahmad-Reza Baghi Hossein Ziaie Mehdi Yaseri

PURPOSE To compare spherical aberration and contrast sensitivity function following implantation of four different foldable posterior chamber intraocular lenses (IOLs), namely Sensar, Akreos AO, Tecnis, and AcrySof IQ. METHODS In this randomized clinical trial, 68 eyes of 68 patients with senile cataracts underwent phacoemulsification and IOL implantation with Sensar (n=17), Akreos AO (n=17),...

Journal: :Optics express 2002
Yoshiaki Yasuno T Yatagai T Wiesendanger A Ruprecht H Tiziani

We propose a high-speed, parallel system for lens aberration measurement employing a confocal optical setup. This method uses a non-interferometric, conventional confocal axial response to determine the spherical aberration coefficient of a confocal objective. The aberration coefficients are successfully calculated from the intensity axial response by employing a neural network. It is estimated...

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