<p>Retinal image light distributions in a standard optical model of a diffraction-limited eye with round pupils are presented for several patterns of amplitude and phase modulation of the light admitted into the eye. Of special interest are circularly symmetrical configurations of truncated Bessel amplitude transmission functions, and of light subjected to axicon deviation. It is shown by several examples that this kind of beam shaping allows generation of retinal imagery, which can be more robust to defocus while maintaining minimal image degradation, and it points to situations of two separate zones simultaneously in sharp focus, several diopters apart.We introduce a new kind of partially coherent source whose cross-spectral density (CSD) function is described as the incoherent superposition of elliptical twisted Gaussian Schell-model sources with different beam widths and transverse coherence widths, named twisted elliptical multi-Gaussian Schell-model (TEMGSM) beams. Analytical expression for the CSD function propagating through a paraxial ABCD optical system is derived with the help of the generalized Collins formula. Our results show that the TEMGSM beam is capable of generating a flat-topped elliptical beam profile in the far field, and the beam spot during propagation exhibits clockwise/anti-clockwise rotation with respect to its propagation axis. In addition, the analytical expressions for the orbital angular momentum (OAM) and the propagation factor are also derived by means of the Wigner distribution function. The influences of the twisted factor and the beam index on the OAM and the propagation factor are studied and discussed in detail.We report on the generation of a hollow Bessel beam with a hole along the direction of propagation by using an easy-to-implement phase mask and investigate its effectiveness to reduce the out-of-focus background in light-sheet fluorescence microscopy (LSFM) with scanned Bessel beams by subtraction imaging. Overlaying $\pi $π-phase retardation between the two equal parts of the Bessel beam across the entrance pupil of the objective lens, a hollow Bessel beam with zero intensity at the focal plane can be achieved. By optimizing the numerical aperture of the annular mask applied in the hollow Bessel beam, matched distributions of the ring system between the hollow Bessel beam and the conventional Bessel beam are achieved. By subtraction between the two LSFM images, the out-of-focus blur caused by the ring system of the Bessel beam can be significantly reduced. Comparison with conventional Bessel LSFM images exhibits a better sectioning capability and higher contrast.We introduce a numerical method that enables efficient modeling of light scattering by large, disordered ensembles of non-spherical particles incorporated in stratified media, including when the particles are in close vicinity to each other, to planar interfaces, and/or to localized light sources. The method consists of finding a small set of fictitious polarizable elements-or numerical dipoles-that quantitatively reproduces the field scattered by an individual particle for any excitation and at an arbitrary distance from the particle surface. The set of numerical dipoles is described by a global polarizability matrix that is determined numerically by solving an inverse problem relying on fullwave simulations. The latter are classical and may be performed with any Maxwell's equations solver. Spatial non-locality is an important feature of the numerical dipoles set, providing additional degrees of freedom compared to classical coupled dipoles to reconstruct complex scattered fields. Once the polarizability matrix describing scattering by an individual particle is determined, the multiple scattering problem by ensembles of such particles in stratified media can be solved using a Green tensor formalism and only a few numerical dipoles, thereby with a low physical memory usage, even for dense systems in close vicinity to interfaces. The performance of the method is studied with the example of large high-aspect-ratio high-index dielectric cylinders. The method is easy to implement and may offer new possibilities for the study of complex nanostructured surfaces, which are becoming widespread in emerging photonic technologies.The scattering process of electromagnetic plane waves by a resistive half-screen is investigated for oblique incidence. First of all, it is shown that the existing solution in the literature is not correct, because the problem was solved by considering the normal components of the electromagnetic field, in terms of which the boundary conditions cannot be expressed. Instead of these, the components of the electric field, which is parallel to the edge discontinuity, are taken into account. The diffracted fields are obtained with the aid of the method of transition boundary. The uniform field expressions are obtained by using the Fresnel function. The behaviors of the total field and its subcomponents are analyzed numerically.We present a new method for automatic adjustment of camera exposure time for visual-servo systems.  <a href="https://www.selleckchem.com/products/5-n-ethyl-n-isopropyl-amiloride-eipa.html">5-(N-Ethyl-N-isopropyl)-Amiloride ic50</a> The proposed method can improve the robustness of image processing in a high-dynamic-range environment. In this paper, we evaluate an appropriate exposure time by computing the local gradient information of a target area, allowing a camera to capture images without losing target features under artificially adjusted illumination conditions. To validate the advantage of the proposed method, an evaluation is made using an off-the-shelf visual-servo system with a machine vision camera. The experimental results demonstrate the effectiveness of our method, which improves the performance of the target recognition algorithm.In this paper, we present the design of a silicon optoelectronic device capable of speeding up processing capabilities. The data in this device are electronic, while the modulation control is optical. It can be used as a building block for the development of optical data processing by silicon-based processors based on typical microelectronics manufacturing processes. A V-groove-based structure fabricated as part of the device allows obtaining enhanced sensitivity to the polarization of the photonic control signal and thus allows obtaining a polarization-sensitive modulator.</p>