نتایج جستجو برای: wavefront

تعداد نتایج: 4736  

Journal: :Journal of refractive surgery 2016
Virgilio Galvis Alejandro Tello Néstor I Carreño Rubén D Berrospi Camilo A Niño

We read with interest the article by Kung and Manche in the April 2016 issue.1 In the first part of the article, they explained that most studies seemed to suggest that the wavefront-guided excimer laser procedures were slightly superior than wavefront-optimized approaches, particularly in patients with preoperative root mean square (RMS) of higher order aberrations (HOAs) less than 0.3 μm. How...

2001
S. C. West D. Fisher

The theory, optical, mechanical, and software design for an interferometric Hartmann wavefront analyzer for the 6.5 m MMT is presented. The instrument is modular so it can be used at the prime focus or any of the three unique Cassegrain foci. We discuss the first results at the f/9 Cass focus where the detected wavefront error was used to correct both collimation and the primary mirror figure d...

2008
C Paterson

The performance of adaptive optics systems, such as for astronomical telescopes, is often limited by the available light for wavefront sensing. The efficiency of the wavefront sensor is therefore of vital importance. We have recently used a Fisher information approach to derive a fundamental limit for the measurement of wavefront phase for adaptive optics systems at low light levels. The limit,...

Journal: :The Review of scientific instruments 2010
G R Plateau N H Matlis C G R Geddes A J Gonsalves S Shiraishi C Lin R A van Mourik W P Leemans

Characterization of the electron density in laser produced plasmas is presented using direct wavefront analysis of a probe laser beam. The performance of a laser-driven plasma-wakefield accelerator depends on the plasma wavelength and hence on the electron density. Density measurements using a conventional folded-wave interferometer and using a commercial wavefront sensor are compared for diffe...

Journal: :Optics express 2014
Gregory A Howland Daniel J Lum John C Howell

We demonstrate a wavefront sensor that unites weak measurement and the compressive-sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field's transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random proj...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2011
Samuel T Thurman

A method is described for analyzing point source imagery collected with various amounts of defocus to obtain wavefront slope data at the exit pupil of an imaging system. Integration of this slope data yields the system wavefront aberration function. The method is based on a geometric optics interpretation of intensity point spread function measurements in the caustic region near focus. Algorith...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2007
Patrick P Lu Amber L Bullington Peter Beyersdorf Stefan Traeger Justin Mansell Ray Beausoleil Eric K Gustafson Robert L Byer Martin M Fejer

It may be advantageous in advanced gravitational-wave detectors to replace conventional beam splitters and Fabry-Perot input mirrors with diffractive elements. In each of these applications, the wavefront distortions produced by the absorption and subsequent heating of the grating can limit the maximum useful optical power. We present data on the wavefront distortions induced in a laser probe b...

2014
Lola Bajard Luis G. Morelli Saúl Ares Jacques Pécréaux Frank Jülicher Andrew C. Oates

How signaling gradients supply positional information in a field of moving cells is an unsolved question in patterning and morphogenesis. Here, we ask how a Wnt signaling gradient regulates the dynamics of a wavefront of cellular change in a flow of cells during somitogenesis. Using time-controlled perturbations of Wnt signaling in the zebrafish embryo, we changed segment length without alterin...

Journal: :Optics express 2006
Anna Burvall Elizabeth Daly Stéphane R Chamot Christopher Dainty

The pyramid wavefront sensor is very similar to the Fourier knife-edge test, but employs dynamic modulation to quantify the phase derivative. For circular modulation, we compare approximate geometrical optics calculations, more exact diffraction calculations, and experimental results. We show that both the sinusoidal and the approximate linear relationship between wavefront derivative and wavef...

Journal: :Applied optics 2012
Sergio Barbero

The aim of this work was to study, using numerical simulations, the attainable level of accuracy to reconstruct the wavefront aberrations from tangential refractive power data measured with dynamic skiascopy. Two mathematical methods have been implemented. The first one is based on curve integration of the curvature data, previously interpolated with cubic splines. The second one reconstructs t...

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