نتایج جستجو برای: wavefront
تعداد نتایج: 4736 فیلتر نتایج به سال:
We demonstrate experimentally that optical wavefront shaping selectively couples light into the fundamental diffusion mode of a scattering medium. The total energy density inside a scattering medium of zinc oxide (ZnO) nanoparticles was probed by measuring the emitted fluorescent power of spheres that were randomly positioned inside the medium. The fluorescent power of an optimized incident wav...
The wave-equation wavefront migration (WWM) is a potentially efficient form of wave equation migration, where the finite-difference stencil is only applied around the leading portion of the wavefront. WWM has the accuracy of wave-equation migration, fewer aliasing and migration artifacts, and can potentially be much faster than the standard reverse-time migration. The potential drawbacks are th...
A three-dimensional wide-field image of a small fluorescent bead contains more than enough information to accurately calculate the wavefront in the microscope objective back pupil plane using the phase retrieval technique. The phase-retrieved wavefront can then be used to set a deformable mirror to correct the point-spread function (PSF) of the microscope without the use of a wavefront sensor. ...
Precision guided munitions(PGM) including cruise missiles are soon expected to fly with advanced seekers having 2D or 3D imaging capabilities for automatic target recognition(ATR) and terminal guidance against tactical targets. Advanced seekers usually are of dual or multi-mode in nature often with combination of Laser, IR, SAR and MMW imaging capabilities. LWIR and LADAR based electro-optical ...
Adaptive optics widefield microscope corrections using a MEMS DM and Shack-Hartmann wavefront sensor
We demonstrated the used of an adaptive optic system in biological imaging to improve the imaging characteristics of a wide field microscope. A crimson red fluorescent bead emitting light at 650 nm was used together with a ShackHartmann wavefront sensor and deformable mirror to compensate for the aberrations introduce by a Drosophila embryo. The measurement and correction at one wavelength impr...
The wavefront retrieval by gradient descent algorithm that is typically applied to coherent or incoherent imaging is extended to retrieve a wavefront from a series of through-focus images by partially coherent illumination. For accurate retrieval, we modeled partial coherence as well as object transmittance into the gradient descent algorithm. However, this modeling increases the computation ti...
An important consideration in the design of an adaptive optics controller is the range of physical shapes required by the DM to compensate the existing aberrations. Conversely, if the range of surface shapes achievable with a DM is known, its suitability for a particular AO application can be determined. In this paper, we characterize one MEMS DM that was recently developed for vision science a...
PURPOSE To examine the relationship between uncorrected residual wavefront error and visual performance (VP) in rigid gas permeable (RGP) contact lens-wearing keratoconic eyes. METHODS Seven eyes from six subjects (six moderate, one severe) were studied (mean +/- SD age: 42.71 +/- 11.38 years). Significant corneal scarring was an exclusion criterion. Measurements were taken with RGP lenses in...
Analyzing measurements of the LOPES antenna array together with corresponding CoREAS simulations for more than 300 measured events with energy above 10 eV and zenith angles smaller than 45◦, we find that the radio wavefront of cosmic-ray air showers is of approximately hyperbolic shape. The simulations predict a slightly steeper wavefront towards East than towards West, but this asymmetry is ne...
We have measured the wavefront and the divergence of the Beamlet prototype laser under a variety of conditions. Emphasis of the tests was on quantifying best attainable divergence in the angular regime below 30 prad to benchmark propagation models that are used to set wavefront gradient specifications for NIF optical components. Performance with and without active wavefront correction was monit...
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