Results 41 to 50 of about 106,212 (345)

Flow structure and optical beam propagation in high-Reynolds-number gas-phase shear layers and jets [PDF]

open access: yes, 2001
We report on the structure of the scalar index-of-refraction field generated by turbulent, gas-phase, incompressible and compressible shear layers and incompressible jets, and on associated beam-propagation aero-optical phenomena.
Catrakis, H. J.   +2 more
core   +1 more source

Optical Aberrations and Wavefront

open access: yesTürk Oftalmoloji Dergisi, 2014
The deviation of light to create normal retinal image in the optical system is called aberration. Aberrations are divided two subgroup: low-order aberrations (defocus: spherical and cylindrical refractive errors) and high-order aberrations (coma ...
Nihat Polat   +2 more
doaj   +1 more source

Stability of traveling wavefronts in discrete reaction-diffusion equations with nonlocal delay effects [PDF]

open access: yes, 2014
This paper deals with traveling wavefronts for temporally delayed, spatially discrete reaction-diffusion equations. Using a combination of the weighted energy method and the Green function technique, we prove that all noncritical wavefronts are globally exponentially stable, and critical wavefronts are globally algebraically stable when the initial ...
arxiv   +1 more source

Propagation of singularities under Schrödinger equations on manifolds with ends [PDF]

open access: yesarXiv, 2022
We prove a microlocal smoothing effect of Schr\"odinger equations on manifolds. We employ radially homogeneous wavefront sets introduced by Ito and Nakamura (Amer. J. Math., 2009). In terms of radially homogeneous wavefront sets, we can apply our theory to both of asymptotically conical and hyperbolic manifolds.
arxiv  

Influence of Image Processing Method on Wavefront Reconstruction Accuracy of Large-Aperture Laser

open access: yesPhotonics, 2023
In order to improve the wavefront reconstruction accuracy of a large-aperture laser, this paper proposed an adaptive window preprocessing algorithm based on the threshold center of gravity method (AW-TCoG).
Gangyu Wang   +5 more
doaj   +1 more source

High Sensitivity Wavefront Sensing with a non-linear Curvature Wavefront Sensor [PDF]

open access: yes, 2009
A new wavefront sensing approach, derived from the successful curvature wavefront sensing concept but using a non-linear phase retrieval wavefront reconstruction scheme, is described. The non-linear curvature wavefront sensor (nlCWFS) approaches the theoretical sensitivity limit imposed by fundamental physics by taking full advantage of wavefront ...
arxiv   +1 more source

Reflective Focusing Based on Few-Layer Gradient Metasurface Element Array

open access: yesFrontiers in Physics, 2020
This study proposes a three-layer focusing gradient metasurface for wavefront processing. The structure works in the frequency range of 15–25 GHz and has a central frequency of 19.6 GHz.
Mengyao Yan   +4 more
doaj   +1 more source

Deep Learning-Based Prediction Algorithm on Atmospheric Turbulence-Induced Wavefront for Adaptive Optics

open access: yesIEEE Photonics Journal, 2022
Correction performance of an adaptive optics (AO) system is severely limited by its system latency under high temporal frequency distortions. Wavefront prediction methods has been proven to be an effective way to compensate system delay.
Ning Wang   +8 more
doaj   +1 more source

Slowly oscillating wavefronts of the KPP-Fisher delayed equation [PDF]

open access: yesDiscrete and Continuous Dynamical Systems - A 34 (2014) 3511 - 3533, 2012
This paper concerns the semi-wavefronts (i.e. bounded solutions $u=\phi(x \nu +ct) >0,$ $ |\nu|=1, $ satisfying $\phi(-\infty)=0$) to the delayed KPP-Fisher equation $$u_t(t,x) = \Delta u(t,x) + u(t,x)(1-u(t-\tau,x)), \ u \geq 0,\ x \in \R^m. \eqno(*)$$ First, we show that each semi-wavefront should be either monotone or slowly oscillating.
arxiv   +1 more source

The Deformable Mirror Demonstration Mission (DeMi) CubeSat: optomechanical design validation and laboratory calibration

open access: yes, 2018
Coronagraphs on future space telescopes will require precise wavefront correction to detect Earth-like exoplanets near their host stars. High-actuator count microelectromechanical system (MEMS) deformable mirrors provide wavefront control with low size ...
Allan, Gregory   +11 more
core   +1 more source

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