نتایج جستجو برای: spherical aberration

تعداد نتایج: 53854  

Journal: :Optics letters 1994
A Beléndez L Carretero A Fimia

The effect of third-order balanced spherical aberration on the axial irradiance of holographic lenses is considered. It is shown that the number of principal maxima of axial irradiance increases for large aberrations, and the position of these points can be different from the position of the minimum aberration variance point.

Journal: :Journal of cataract and refractive surgery 2002
Sergio Barbero Susana Marcos Jesús Merayo-Lloves

PURPOSE To measure corneal and total optical aberrations in the normal and treated eye of a unilateral aphakic patient to (1) cross-validate techniques in an eye in which corneal and total aberrations should be almost identical (aphakic eye) and (2) compare the interactions of corneal and internal aberrations in the normal eye with those in the aphakic eye. SETTING Instituto de Optica, Consej...

2013
Tomo Nishi Futoshi Taketani Tetsuo Ueda Nahoko Ogata

PURPOSE To determine the amplitude of pseudoaccommodation and higher-order aberrations with three types of implanted monofocal intraocular lenses (IOLs): aspheric yellow (IQ); spheric yellow (NT); and spheric clear (AT). SETTING Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS We studied 60 patients who underwent small incision phacoemulsification with the implanta...

Journal: :Vision Research 2008
Susana Marcos Patricia Rosales Lourdes Llorente Sergio Barbero I. Jiménez-Alfaro

It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma. It has been debated whether the compensation of horizontal coma is the result of passive mechanism [Artal, P., Benito,...

Journal: :Ultramicroscopy 2016
J P S Fitzgerald R C Word R Könenkamp

We present theoretical estimates of the mean coefficients of spherical and chromatic aberration for low energy photoemission electron microscopy (PEEM). Using simple analytic models, we find that the aberration coefficients depend primarily on the difference between the photon energy and the photoemission threshold, as expected. However, the shape of the photoelectron spectral distribution impa...

2010
P Wang G Behan A I Kirkland P D Nellist

Scanning confocal electron microscopy (SCEM) is a new imaging mode in electron microscopy. Spherical aberration corrected electron microscope instruments fitted with two aberration correctors can be used in this mode which provides improved depth resolution and selectivity compared to optical sectioning in a conventional scanning transmission geometry. In this article, we consider a confocal op...

2007
Kuniyasu Nakamura Hiromi Inada Hiroyuki Tanaka Mitsuru Konno Taro Ogawa

INTRODUCTION AS VLSI (very large scale integration) technology evolves toward ever smaller features and multilayer designs, analysis and control of structures and compositions at the atomic level is becoming increasingly important. In 1998 Hitachi HighTechnologies Corporation released the HD-2000, a STEM (scanning transmission electron microscope) that was very well received for combining the e...

Journal: :Applied optics 1993
L Carretero C González A Fimia I Pascual

We studied the spherical aberration of an intraocular lens, using third-order theory, ray tracing, and bench measurements by the Ronchi test. Good agreement was obtained for these three methods of investigation. In particular we found that the Ronchi test is an accurate method for quantifying this aberration.

Journal: :Journal of physics 2021

The precision and work efficiency of the distributed repeat projection lithography machine (DSW) directly affect special requirements large-scale integrated circuit production process. In order to improve exposure imaging accuracy projection, paper proposes object image difference in-situ detection (AMF) technology based on particle swarm optimization. article analyzes basic principles this usi...

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