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Ritter Coyne posted an update 2 days, 10 hours ago
The retrieved structure was above the detector edge resolution and clearly showed the pseudo-icosahedral capsid of the PR772.A set of laser beams carrying orbital angular momentum is designed with the objective of establishing an effective underwater communication link. Messages are constructed using unique Laguerre-Gauss beams, which can be combined to represent four bits of information. We report on the experimental results where the beams are transmitted through highly turbid water, reaching approximately 12 attenuation lengths. We measured the signal-to-noise ratio in each test scenario to provide characterization of the underwater environment. A convolutional neural network was developed to decode the received images with the objective of successfully classifying messages quickly. We demonstrate near-perfect classification in all scenarios, provided the training set includes some images taken under the same underwater conditions.We propose an analytical solution of the focal ring generated at the focus of a toric lens. The analytical field of the focal ring is used with a Fourier transform lens to generate a Bessel beam. A comparative analysis between the use of an illuminated annular aperture, an axicon, and a toric lens to generate a Bessel beam is performed, and the benefits and drawbacks of each are discussed. This highlights the advantages of using a toric lens with a Gaussian beam to produce a focal line of increasing intensity, which is advantageous for applications such as high depth-of-field microscopy.In this work, we report experiments and a theoretical scheme of photon transport in the frequency domain of rigid turbid media. We have employed spectral multi-speckle intensity correlations to estimate optical properties as the transport mean free path and the absorption length of turbid systems. We propose a scheme based on the photon diffusion model using an effective path-length distribution in the backscattering configuration and take explicitly into account the particles scattering anisotropy parameter g. By studying rigid Teflon slabs and polymer matrices doped with polystyrene particles of different degrees of scattering anisotropy, we find that the proposed model adequately describes our experimental results. Our hypothesis for the diffuse transport of backscattered photons in the weak multiple scattering regime is further validated using a numerical simulation scheme of speckle dynamics, based on the Copula method.Image scanning microscopy is a technique of confocal microscopy in which the confocal pinhole is replaced by a detector array, and the image is reconstructed most straightforwardly by pixel reassignment. In the fluorescence mode, the detector array collects most of the fluorescent light, so the signal-to-noise ratio is much improved compared with confocal microscopy with a small pinhole, while the resolution is improved compared with conventional fluorescence microscopy. read more Here we consider two cases in which the illumination and detection point spread functions are dissimilar illumination with a Bessel beam and multiphoton microscopy. It has been shown previously that for Bessel beam illumination in image scanning microscopy with a large array, the imaging performance is degraded. On the other hand, it is also known that the resolution of confocal microscopy is improved by Bessel beam illumination. Here we analyze image scanning microscopy with Bessel beam illumination together with a small array and show that a factor 2.13 better than in standard two-photon fluorescence. Axial resolution and optical sectioning in two-photon or three-photon fluorescence are also improved by using the image scanning modality.In a recent analysis [J. Quant. Spectrosc. Radiat. Transfer250, 106994 (2020)JQSRAE0022-407310.1016/j.jqsrt.2020.106994], the emergence of a dynamic oscillatory radiation force in coherent optical/electromagnetic (EM) heterodyning has been demonstrated for TM- and TE-polarized amplitude-modulated (AM) plane waves interacting with a lossless dielectric circular cylinder. A dynamic oscillatory component of the EM radiation force emerged at the beat frequency of two interfering fully correlated wave fields driven at slightly different frequencies. This work extends the scope of that analysis to examine the oscillatory behavior of energy-related physical observables from the standpoint of energy conservation applied to scattering. Partial-wave series for the oscillatory scattering, extinction and absorption powers, cross sections, and energy efficiencies are derived in cylindrical coordinates for a circular homogeneous cylinder material using the short-term time averaging (STTA) procedure and Poynting’s theorem. sis is of fundamental importance in order to validate dynamic radiation force computational results from the standpoint of energy conservation in the development, design, and optimization of oscillatory optical heterodyne tweezers and tractor beams in related applications in particle manipulation.The influence of anisotropic weak-to-strong oceanic turbulence on the performance of underwater optical communication (UWOC) systems is investigated in this paper. The Málaga distribution fading model is used to model the statistical distribution of a spherical wave propagating through anisotropic oceanic turbulence, which is a versatile model of weak-to-strong turbulence. First, the scintillation index for a spherical wave propagating in oceanic turbulence is formulated, and closed-form expressions for the outage probability and average channel capacity of the UWOC systems are then proposed in terms of Meijer’s G function. The simulation results demonstrate that both the outage probability and the average channel capacity strongly depend on the parameters of oceanic turbulence, such as the ratio of temperature to the contribution of salinity to the refractive index spectrum, the rate of dissipation of kinetic energy per unit mass of fluid, and the rate of dissipation of mean-squared temperature; they are also related to system parameters such as wavelength and aperture diameter. Numerical results are provided to verify the accuracy of our proposed expressions for outage probability and average channel capacity, and perfect agreement is observed.