We introduce and analyze several algorithms for optimal illumination in array imaging. We consider time reversal and Kirchhoff migration imaging in homogeneous media, in regimes where the signal-to-noise ratio is high (infinite). Extensions to coherent interferometric imaging in clutter are described briefly. We show with numerical simulations that the optimal illumination algorithms image sele...

The class of second-order curvilinear gratings consists of all the curvilinear gratings that are obtained by second-order spatial transformations of periodic gratings. It includes, for example, circular, elliptic, and hyperbolic gratings as well as circular, elliptic, and hyperbolic zone plates. Such structures occur quite frequently in optics, and their Fourier transforms may arise, for instan...

Luara Ferreira dos Santos, Rehabilitation Robotics Group (TU Berlin/ Fraunhofer IPK), Technische Universität Berlin, Department of Industrial Automation Technology, Germany Thomas Schüler, SALT AND PEPPER, Software Solution Center & University of Osnabrück, Germany Simon Hoermann, Department of Medicine (DSM) & Department of Information Science, University of Otago, New Zealand Henning Schmidt,...

Lukas Pauscher 1,2,∗, Nikola Vasiljevic 3, Doron Callies 1, Guillaume Lea 3, Jakob Mann 3, Tobias Klaas 1,4, Julian Hieronimus 5, Julia Gottschall 6, Annedore Schwesig 1, Martin Kühn 5 and Michael Courtney 3 1 Fraunhofer Institute for Wind Energy and Energy System Technology (IWES), Fraunhofer IWES|Kassel, Königstor 59, 34119 Kassel, Germany; [email protected] (D.C.); tobias.klaa...

The phase matrix and several quantities for single scattering by an arbitrarily oriented circular cylinder are formulated by using the approximation of ray optics, which includes geometrical reflection and refraction plus Fraunhofer diffraction; then the effects of polarization are considered. Computations were made using electromagnetic wave theory and ray optics approximations for m = 1.31-0....

A method to solve of the phase retrieval problem in a non-convex formulation for complex-valued objects with support constraint is proposed. It shown that two coded diffraction patterns (CDPs) obtained same Fresnel or Fraunhofer plane by masking an object two, direct and inverse, random binary amplitude masks, are sufficient reconstruct arbitrary up global phase. The general solution was found ...

We provide an experimental detailed study of the three-dimensional coherence properties of light speckles produced by different tunable pseudothermal sources. Our findings confirm the theoretical prediction of the companion article A. Gatti et al., Phys. Rev. A 78, 063806 2008 , according to which the longitudinal coherence of the speckles is ruled by ordinary diffraction laws only in the deep-...

We have proposed an optical method that can be applied to in-process or in situ measurement of the microsurface profile. The present method is based on optically performed spectral analysis and the phase retrieval technique. Spectral information of a surface profile is obtained by measuring the Fraunhofer diffraction intensity. The phase retrieval technique is used to reconstruct the surface pr...

Physical insights and characteristics of beam transformations based on multimode interference (MMI) in multimode waveguides are illuminated and analyzed. Our calculations show that, utilizing a short piece of cylindrical multimode waveguide, an input Gaussian beam can be readily transformed to frequently desired beams including top-hat, donut-shaped, taper-shaped, and Bessel-like beams in the F...

This manuscript describes how to classify nematodes using temporal far-field diffraction signatures. A single C. elegans is suspended in a water column inside an optical cuvette. A 632 nm continuous wave HeNe laser is directed through the cuvette using front surface mirrors. A significant distance of at least 20-30 cm traveled after the light passes through the cuvette ensures a useful far-fiel...