Results 81 to 90 of about 5,509 (162)

Simultaneously measuring ocular aberration and anterior segment biometry during accommodation [PDF]

Journal of Innovative Optical Health Sciences, 2015
In the human eye, accommodation is essential for functional vision. However, the mechanisms regulating accommodation and the ocular parameters affecting aberrations remain to be explored.
Yuanyuan Wang, Yilei Shao, Yimin Yuan
doaj   +1 more source

On-sky multi-wavelength phasing of segmented telescopes with the Zernike phase contrast sensor

, 2011
Future Extremely Large Telescopes will adopt segmented primary mirrors with several hundreds of segments. Cophasing of the segments together is essential to reach high wavefront quality.
Cavarroc, Chanan, Chanan, Dohlen, Dohlen, Dupuy, Gilmozzi, Gonte, Houairi, Lofdahl, Martinez, Mazzoleni, Montoya-Martínez, Nelson, Pinna, Polhemus, Surdej, Wilhelm, Yaitskova, Yaitskova, Zernike   +20 more
core   +3 more sources

Review and experimental comparison of speckle‐tracking algorithms for X‐ray phase contrast imaging

Journal of Synchrotron Radiation, Volume 32, Issue 1, Page 180-199, January 2025.
This review focuses on low‐dose near‐field X‐ray speckle phase imaging in the differential mode introducing the existing algorithms with their specifications and comparing their performances under various experimental conditions.X‐ray speckles have been used in a wide range of experiments, including imaging (and tomography), wavefront sensing, spatial ...
Rafael Celestre, Laurène Quénot, Christopher Ninham, Emmanuel Brun, Luca Fardin   +4 more
wiley   +1 more source

Sources of reduced visual acuity and spectacle treatment options for individuals with Down syndrome: Review of current literature

Ophthalmic and Physiological Optics, Volume 44, Issue 7, Page 1326-1345, November 2024.
Abstract Individuals with Down syndrome are known to have a greater prevalence of ocular conditions such as strabismus, nystagmus, elevated refractive error, poor accommodative function, elevated higher‐order optical aberrations and corneal abnormalities.
Heather A. Anderson
wiley   +1 more source

Coherence vortices by binary pinholes

Nanophotonics, Volume 13, Issue 24, Page 4397-4407, November 2024.
Abstract Singularity in a two‐point complex coherence function, known as coherence vortices, represents zero visibility with a helical phase structure. In this paper, we introduce a novel technique to generate the coherence vortices of different topological charges by incoherent source transmittance with exotic structured binary pinholes.
Akanksha Gautam, Amit K. Agarwal, Rakesh Kumar Singh   +2 more
wiley   +1 more source

High‐angular‐sensitivity X‐ray phase‐contrast microtomography of soft tissue through a two‐directional beam‐tracking synchrotron set‐up

Journal of Synchrotron Radiation, Volume 31, Issue 5, Page 1293-1298, September 2024.
X‐ray phase‐contrast microtomography is demonstrated using two‐dimensional amplitude modulation of the beam. The implementation is characterised in terms of angular sensitivity and spatial resolution, and its application to the three‐dimensional imaging of biological soft tissues is shown.Two‐directional beam‐tracking (2DBT) is a method for phase ...
Carlos Navarrete-León, P. Stephen Patrick, Adam Doherty, Harry Allan, Silvia Cipiccia, Shashidhara Marathe, Kaz Wanelik, Michela Esposito, Charlotte K. Hagen, Alessandro Olivo, Marco Endrizzi   +10 more
wiley   +1 more source

Correction of wavefront rotation between interferometer and shack-hartmann sensor using bending modes

Journal of the European Optical Society-Rapid Publications, 2020
In some active optics system, the influence function, which is the surface deformation ability of an actuator, is measured by directly detecting the mirror surface using an interferometer and the surface correction of the primary mirror is done using the
Yi Zhu, Tao Chen, Hongzhuang Li
doaj   +1 more source

Broadband, Common-Path, Interferometric Wavefront Sensor [PDF]

Hybrid sensors comprising Shack-Hartmann Wavefront Sensor (S-HWFS) and Zernike Wavefront Sensor (Z-WFS) capabilities are presented. The hybrid sensor includes a Z-WFS optically arranged in-line with a S-HWFS such that the combined wavefront sensor ...
Wallace, James Kent
core   +1 more source

The Magellan Adaptive Secondary VisAO Camera: Diffraction- Limited Broadband Visible Imaging and 20mas Fiber Array IFS

, 2010
The Magellan Adaptive Secondary AO system, scheduled for first light in the fall of 2011, will be able to simultaneously perform diffraction limited AO science in both the mid-IR, using the BLINC/MIRAC4 10\{mu}m camera, and in the visible using our novel
Close, Laird M., Follette, Katherine, Gasho, Victor, Kopon, Derek, Males, Jared R.   +4 more
core   +1 more source

Thermal analysis and experimental study of end-pumped Nd: YLF laser at 1053 nm

Photonic Sensors, 2017
We have numerically analyzed the thermal effects in Nd: YLF laser rod. The calculations of temperature and stress distributions in the Nd: YLF laser rod was performed with finite element (FE) simulations.
R. M. El-Agmy, N. Al-Hosiny
doaj   +1 more source