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Ruediger Schmid,1 Andreas F Borkenstein2 1accuratis, Practice for Refractive Eye Surgery, Ulm, 89073, Germany; 2Borkenstein & Borkenstein, Private Practice at Privatklinik der Kreuzschwestern, Graz, 8010, AustriaCorrespondence: Ruediger Schmid, accuratis, Practice for Refractive Eye Surgery, Hirschstrasse 1, Ulm, 89073, Germany, Tel +49 731 28065680, Email dr.schmid@accuratis-ulm.dePurpose: Any new intraocular lens (IOL) on the market claims to outperform competitors. We aimed to estimate the modulation transfer function (MTF) for different defocus of a novel refractive enhanced depth of focus (EDoF) IOL and the simulated visual acuity over this range of vision. Further, we analyzed the wavefront pattern produced by this IOL to reveal the function of the IOL’s optics.Methods: For the novel TECNIS® PureSee® (ZEN00V) IOL, through frequency and through focus MTF were recorded on the optical bench (ISO-2 Cornea 0.28 μm, 546 nm). MTFa and the simulated visual acuity were calculated for different defocus. Apertures of 3 mm and 4.5 mm were applied. Higher order aberrations of the IOLs’ optics were recorded and analyzed.Results: PureSee® IOL demonstrated a considerable depth of focus of about 1.7 D at the spectacle plane and a continuous simulated visual acuity over this range of defocus. For the 4.5 mm aperture, near focus depth was reduced, yet far distance MTF was even better. Higher order aberrations revealed increased primary and secondary spherical aberrations.Conclusion: Optical bench results suggest that the new ZEN00V matches the clinical criteria of an EDoF IOL by an increased range of vision and is far distance dominant for an enlarged pupil. This behaviour seems to be due to subtle power changes in the central optics that produce a complex modification of wavefront.Keywords: modulation transfer function, optical bench, intraocular lens, EDoF, wavefront, enhanced depth of focus

Purpose: to assess the state of the wavefront in children with myopia, who have various manifestations of digital eye strain and symptoms of ocular surface disorders, and to evaluate the diagnostic significance of wavefront criteria for assessing the state of the ocular surface.Patients and methods. The study involved 76 children (152 eyes) with myopia aged 8 to 18 years who used gadgets and computers for more than 2 hours a day. All patients used glasses as a method of optical correction and were constantly worn. The patients were divided into 2 groups: 1st with symptoms of ocular surface disorder, 2nd — comparison group. Subjective signs were studied using the online questionnaire “State of the ocular surface”. Using the “Keratograph 5M Oculus” the following parameters were assessed: non­invasive tear film breakup time (NTBR), including the first tear film breakup time, average tear film breakup time, breakup time gradient and maximum tear film breakup zone, the same device was used to perform infrared meibography and study of the lipid layer of the tear film. All patients underwent wavefront aberrometry in a darkened room without cycloplegia.Results. It was found that in the group of patients with the presence of subjective phenomena of disturbance of the state of the ocular surface, identified using the online questionnaire “State of the ocular surface”, rotor aberrations were statistically significantly higher than in the comparison group. At the same time, the indicators of higher­order corneal aberrations have comparable values. Correlation analysis between indicators of the state of the ocular surface and parameters of the wavefront in the group of children with disturbances of the state of the ocular surface showed that a higher level of corneal aberrations corresponds to a higher number of points on the questionnaire of disturbances of the ocular surface and the state of visual comfort, in turn, when comparing data on non­invasive tear film breakup time, a negative correlation was established, which means that with a higher number of points on the questionnaire, and therefore, with a more significant degree of impairment of the ocular surface, the tear film breakup time was shorter.Conclusion. The structure of the wavefront in children with myopia against the background of a disorder of the ocular surface in combination with CVS and digital eye strain is significantly different from the structure of the wavefront in the comparison group.

Floats are the primary buoyancy component of plastic fish cages in offshore aquaculture. They can increase fish cage stress and deformation under the action of sea currents, and the rise of the float's surface liquid level can cause waves on the fish cage walkway. Although plastic fish cages are a recent development in aquaculture, little research has been conducted on the arrangement of floats. Therefore, studying the resistance performance of floats is significant for safe offshore aquaculture production. This article first studies the resistance of single and double floats through on-site measurement methods. Then, based on viscous flow theory, numerical simulations are carried out to simulate the resistance and waveforms of single and double floats under different flow velocities. The simulation results are compared with the on-site measurement results to verify the accuracy of the numerical simulation. Using the same numerical simulation method as above, numerical simulations are carried out for square and diamond two typical float arrangement forms, to analyze liquid level and resistance under different flow velocities. The results show that the numerical model agrees with the on-site measurement results, with an error of 9. 5%. Three aspects are used to analyze the advantages and disadvantages of square and diamond arrangements. (1) Liquid level rise: When the flow velocity is the same, the total liquid level rise of the diamond-shaped floats arrangement is less than that of the square arrangement. (2) Flow field distribution in the middle of two floats: The flow field between the two floats of square arrangement is more chaotic than that of diamond arrangement. (3) Average resistance: When the flow velocity is greater than 1. 5 m/ s, the resistance of diamond arrangement is 29% less than that of square arrangement. The results of the on-site measurement of the small boat towing test are compared with the results of the numerical simulation output. The resistance and waveforms agree with the test results, proving that the numerical simulation method used in this article is accurate and reliable and can provide technical support for subsequent numerical studies of floats. Analyzing the liquid level situation and liquid level cloud images of the two arrangements shows that the diamond arrangement has more stable liquid level changes and better air gap performance than the square arrangement, so it is more suitable for complex offshore environments. The diamond arrangement can provide a better working environment for offshore aquaculture. By sorting out and analyzing the results of numerical simulation, it is found that the average resistance of square arrangement and diamond arrangement is less than that of individual floats. Further comparing average resistance shows that diamond arrangement has less average resistance than square arrangement, so it is more suitable for complex offshore conditions. Floats are the primary buoyancy components of plastic fishing rafts used in offshore aquaculture. Under the influence of sea currents, the resistance generated by floats can result in increased force and deformation of the fishing raft. Additionally, the elevation of the liquid level on the float's surface can induce waves on the raft platform. Therefore, studying the resistance performance of floats is crucial for ensuring the safety of offshore aquaculture production. The resistance performance of both single and double floats was investigated through practical measurements at sea. Numerical simulations based on viscous flow theory were employed to analyze the resistance and waveform of single and double floats at various flow rates. The accuracy of the numerical simulations was validated by comparing the results with actual sea measurements. Furthermore, numerical simulations were conducted to assess the placement of two typical floats in square and diamond configurations. Liquid surface heights and resistance at different flow rates were analyzed. The findings indicate that numerical simulations align well with actual sea measurements, with an error rate of less than 9. 5%. The diamond-shaped float configuration corresponds to an elevation in the liquid surface, creating a more stable flow field between the two floats. This results in a smaller average resistance, with values below 29% in flow velocities exceeding 1. 5 m/ s. Consequently, it is recommended that this placement configuration be adopted for production operations. [ABSTRACT FROM AUTHOR]

Background: Understanding the dynamics of conduction velocity (CV) and voltage amplitude (VA) is crucial in cardiac electrophysiology, particularly for substrate-based catheter ablations targeting slow conduction zones and low voltage areas. This study utilizes ultra-high-density mapping to investigate the impact of heart rate and pacing location on changes in the wavefront direction, CV, and VA of healthy pig hearts. Methods: We conducted in vivo electrophysiological studies on four healthy juvenile pigs, involving various pacing locations and heart rates. High-resolution electroanatomic mapping was performed during intrinsic normal sinus rhythm (NSR) and electrical pacing. The study encompassed detailed analyses at three levels: entire heart cavities, subregions, and localized 5-mm-diameter circular areas. Linear mixed-effects models were used to analyze the influence of heart rate and pacing location on CV and VA in different regions. Results: An increase in heart rate correlated with an increase in conduction velocity and a decrease in voltage amplitude. Pacing influenced conduction velocity and voltage amplitude. Pacing also influenced conduction velocity and voltage amplitude, with varying effects observed based on the pacing location within different heart cavities. Pacing from the right atrium (RA) decreased CV in all heart cavities. The overall CV and VA changes in the whole heart cavities were not uniformly reflected in all subregions and subregional CV and VA changes were not always reflected in the overall analysis. Overall, there was a notable variability in absolute CV and VA changes attributed to pacing. Conclusions: Heart rate and pacing location influence CV and VA within healthy juvenile pig hearts. Subregion analysis suggests that specific regions of the heart cavities are more susceptible to pacing. High-resolution mapping aids in detecting regional changes, emphasizing the substantial physiological variations in CV and VA. [ABSTRACT FROM AUTHOR]

The effects of temperature on aberrations in the mirrors and lenses of beam delivery systems were analyzed. Aberrations were derived using the Zernike polynomial and a Shack-Hartmann wavefront sensor. As the temperature rose, aberrations became more pronounced; in particular, orthogonal aberrations significantly increased. Computational analysis revealed that the aberrations were attributable to variations in the thermal expansion coefficients of various components of the anisotropic structure. The analytical and experimental results were similar. As the temperature rose, tilt aberrations significantly increased; the y-tilts of mirrors and lenses differed. An optical component realignment method was used to reduce aberrations as the temperature rose. We used the tilting screw to change the position of the second mirror, then used the linear slide to reduce defocusing aberration. These calibrations reduced aberrations to levels comparable with their initial values. [ABSTRACT FROM AUTHOR]

Approaches to constructing algorithms for controlling adaptive optics (AO) systems based on prediction of evolutions of spatial and temporal distributions of phase distortions in the optical wave propagating in an atmospheric turbulence and generation of control signals for correcting wavefront distortions in real time are described. Main patterns of evolutions of phase distortions of optical waves propagating in the Kolmogorov-type turbulent atmosphere are analyzed. An extremely high operating frequency of the Shack–Hartmann-type wavefront sensor has been estimated. Numerical modeling of the AO system operation has been performed in closed and open tracking loops. Errors in estimating the turbulence parameters with the wavefront sensor operating at high frequencies are given. [ABSTRACT FROM AUTHOR]

Introduction: Keratoconus is a progressive disorder of the cornea that causes thinning (Sedaghat et al. in Sci Rep 11(1):11971, 2021), ectasia, and irregular astigmatism, resulting in poor visual acuity that cannot be corrected with standard sphero-cylindrical spectacle lenses. One feature distinguishing keratoconic corneas is ocular aberrations, manifesting up to five or six times the amount of higher-order aberrations than a normal, healthy eye. These aberrations can cause visual disturbances even at the very early stages of the disease. Methods: In the past, a diagnosis was derived from clinical symptoms, but technological advances have revealed multiple pre-clinical features, allowing for the differentiation between keratoconic and normal eyes at a much earlier stage. These include anterior and posterior corneal surface elevations, the corneal pachymetry profile, corneal epithelial patterns, wavefront aberration metrics, and corneal biomechanics (Sedaghat et al. in Sci Rep 11(1):11971, 2021).This review discusses the aberrations associated with keratoconus, how to measure them, and treatment methods to minimize their negative influence. Conclusions: Early diagnosis can lead to early treatment and may allow for arresting progression, thereby improving the long-term prognosis. With the acceleration of refractive surgery, it is important to identify patients with keratoconus, as they are usually contraindicated for refractive surgery. [ABSTRACT FROM AUTHOR]

We prove the existence of the minimal speed of propagation c ⁎ (r , b , K) ∈ [ 2 1 − r , 2 ] for wavefronts in the Belousov-Zhabotinsky system with a spatiotemporal interaction defined by the convolution with (possibly, "fat-tailed") kernel K. The model is assumed to be monostable non-degenerate, i.e. r ∈ (0 , 1). The slowest wavefront is termed pushed or nonlinearly determined if its velocity c ⁎ (r , b , K) > 2 1 − r. We show that c ⁎ (r , b , K) is close to 2 if i) positive system's parameter b is sufficiently large or ii) K is spatially asymmetric to one side (e.g. to the left: in such a case, the influence of the right side concentration of the bromide ion on the dynamics is more significant than the influence of the left side). Consequently, this reveals two reasons for the appearance of pushed wavefronts in the Belousov-Zhabotinsky reaction. [ABSTRACT FROM AUTHOR]

The Fried's length r0, the outer scale L0, the isoplanatism θ0, the coherence time τ0, and the profile of the optical turbulence energy are parameters of the wavefront spatiotemporal coherence. Numerous optical methods are used to determine the images quality through the estimation of the parameters r0, L0, θ0, and τ0, where numerical simulations of the transversal and longitudinal covariance (as a function of the angle-of-arrival (AA)) play a significant role. In this work, we, first, perform the statistical analysis of the fluctuations of angle-of-arrival using theoretical models of the atmospheric turbulence, and second, the statistical analysis of the AA fluctuations in solar limb images. This analysis plays a significant role in the optimization of techniques, such as adaptive optics (OA) and in interferometry, in astronomical observations with high angular resolution. [ABSTRACT FROM AUTHOR]

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New, high-coherent-flux X-ray beamlines at synchrotron and free-electron laser light sources rely on wavefront sensors to achieve and maintain optimal alignment under dynamic operating conditions. This includes feedback to adaptive X-ray optics. We describe the design and modeling of a new class of binary-amplitude reflective gratings for shearing interferometry and Hartmann wavefront sensing. Compact arrays of deeply etched gratings illuminated at glancing incidence can withstand higher power densities than transmission membranes and can be designed to operate across a broad range of photon energies with a fixed grating-to-detector distance. Coherent wave-propagation is used to study the energy bandwidth of individual elements in an array and to set the design parameters. We observe that shearing operates well over a ±10% bandwidth, while Hartmann can be extended to ±30% or more, in our configuration. We apply this methodology to the design of a wavefront sensor for a soft X-ray beamline operating from 230 eV to 1400 eV and model shearing and Hartmann tests in the presence of varying wavefront aberration types and magnitudes.

The transport-of-intensity equation provides a new non-interferometric and non-iterative access to quantitative information about the phase of a light wave by measuring intensity distributions. This equation can be used to implement a simple and accurate spatial phase measurement for optical testing of spherical surfaces. The method requires only a CMOS camera, which records transverse field intensity distributions in several planes. Processing of experimental measurements with specialized software allows one to reconstruct the value of the radius of curvature of the spherical surface under test with high accuracy. The method is compared with measurements made by an interferometer, showing the difference between the values of the surface radius of curvature to be 0.01 % or less and indicating good agreement of the results.

Particulate polymer composites (PPCs) are widely applied under different elastic wave loading conditions in the automobile, aviation, and armor protection industries. This study investigates the elastic wave propagation behavior of a typical PPC, specifically a Cu/poly (methyl methacrylate) (PMMA) composite, with a wide range of particle contents (30–65 vol. %) and particle sizes (1–100 μm). The results demonstrate an inflection phenomenon in both the elastic wave velocity and attenuation coefficient with increasing volume content. In addition, the inflection point moves to the direction of low content with the increase in particle size. Notably, the elastic wave velocity, attenuation, and wavefront width significantly increased with the particle size. The inflection phenomenon of elastic wave propagation behavior in PPCs is demonstrated to have resulted from particle interaction using the classical scattering theory and finite element analysis. The particle interaction initially intensified and then reduced with increasing particle content. This study elucidates the underlying mechanism governing the elastic wave propagation behavior of high particle content PPCs and provides guidelines for the design and application of wave-absorbing composites. [ABSTRACT FROM AUTHOR]

Angle sensors are widely used for wavefront measurements, which is attributed to their integration and robustness. Currently, commercial sensors are available with pixel sizes in the order of wavelengths. However, the spatial resolution of angle sensors still lags far behind. Here, we report a one-dimensional, high-resolution wavefront sensor. It was produced by introducing subwavelength compound gratings above the pixels. The gratings involved could be replaced by the sensor's intrinsic readout circuitry without additional operation. The experimental results showed that it had a spatial resolution of 1.4 µm, two orders of magnitude higher than that of the Shack–Hartmann wavefront sensor. The significant increase in spatial resolution enables angle sensors to reconstruct complex wavefronts accurately. [ABSTRACT FROM AUTHOR]

Enteric nervous system development relies on intestinal colonization by enteric neural crest-derived cells (ENCDCs). This is driven by a population of highly migratory and proliferative ENCDCs at the wavefront, but the molecular characteristics of these cells are unknown. ENCDCs from the wavefront and the trailing region were isolated and subjected to RNA-seq. Wavefront-ENCDCs were transcriptionally distinct from trailing ENCDCs, and temporal modelling confirmed their relative immaturity. This population of ENCDCs exhibited altered expression of ECM and cytoskeletal genes, consistent with a migratory phenotype. Unlike trailing ENCDCs, the wavefront lacked expression of genes related to neuronal or glial maturation. As wavefront ENCDC genes were associated with migration and developmental immaturity, the genes that remain expressed in later progenitor populations may be particularly pertinent to understanding the maintenance of ENCDC progenitor characteristics. Dusp6 expression was specifically upregulated at the wavefront. Inhibiting DUSP6 activity prevented wavefront colonization of the hindgut, and inhibited the migratory ability of post-colonized ENCDCs from midgut and postnatal neurospheres. These effects were reversed by simultaneous inhibition of ERK signaling, indicating that DUSP6-mediated ERK inhibition is required for ENCDC migration in mouse and chick. [ABSTRACT FROM AUTHOR]

Grid cells fire in sequences that represent rapid trajectories in space. During locomotion, theta sequences encode sweeps in position starting slightly behind the animal and ending ahead of it. During quiescence and slow wave sleep, bouts of synchronized activity represent long trajectories called replays, which are well-established in place cells and have been recently reported in grid cells. Theta sequences and replay are hypothesized to facilitate many cognitive functions, but their underlying mechanisms are unknown. One mechanism proposed for grid cell formation is the continuous attractor network. We demonstrate that this established architecture naturally produces theta sequences and replay as distinct consequences of modulating external input. Driving inhibitory interneurons at the theta frequency causes attractor bumps to oscillate in speed and size, which gives rise to theta sequences and phase precession, respectively. Decreasing input drive to all neurons produces traveling wavefronts of activity that are decoded as replays.

The paper presents the results of studies of wavefront distortions at different heights in the atmosphere. We have used measurement wavefront data to determine optical turbulence parameters along the line of sight of the Large Solar Vacuum Telescope. Through cross-correlation analysis of differential motions of sunspots at spaced wavefront sensor subapertures, we determined turbulent parameters at different heights at the Large Solar Vacuum Telescope site. The differential motions of sunspots characterize the small-scale structure of turbulent phase distortions in the atmosphere. Synchronous temporal changes in the amplitude of these distortions at certain regions of the telescope aperture are conditioned by turbulent layers at different heights. We have estimated the contribution of optical turbulence to integral distortions at the telescope aperture for layers 0–0.6, 0.6–1.1, 1.1–1.7 km. The contribution of optical turbulence concentrated in a 1.7 km atmospheric layer to the wavefront distortions at the aperture telescope is shown to be ~43 %.

Due to global warming, wildfires became more severe and frequent than in the past, and more complex mathematics is needed to provide the model of propagation and predict the behavior of the fire. In this work, for a wildfire spreading in some flat land of zero slope, by using Randers metric the equations of wavefronts and wave rays are provided which lead to presenting a more precise and reliable model of propagation. By considering some hypothetical fire in Boa Nova National Park as an example, a simulation is implemented.

Introduction: Scar‐related ventricular tachycardia (VT) usually results from an underlying reentrant circuit facilitated by anatomical and functional barriers. The later are sensitive to the direction of ventricular activation wavefronts. We aim to evaluate the impact of different ventricular activation wavefronts on the functional electrophysiological properties of myocardial tissue. Methods: Patients with ischemic heart disease referred for VT ablation underwent high‐density mapping using Carto®3 (Biosense Webster). Maps were generated during sinus rhythm, right and left ventricular pacing, and analyzed using a new late potential map software, which allows to assess local conduction velocities and facilitates the delineation of intra‐scar conduction corridors (ISCC); and for all stable VTs. Results: In 16 patients, 31 high‐resolution substrate maps from different ventricular activation wavefronts and 7 VT activation maps were obtained. Local abnormal ventricular activities (LAVAs) were found in VT isthmus, but also in noncritical areas. The VT isthmus was localized in areas of LAVAs overlapping surface between the different activation wavefronts. The deceleration zone location differed depending on activation wavefronts. Sixty‐six percent of ISCCs were similarly identified in all activating wavefronts, but the one acting as VT isthmus was simultaneously identified in all activation wavefronts in all cases. Conclusion: Functional based substrate mapping may improve the specificity to localize the most arrhythmogenic regions within the scar, making the use of different activation wavefronts unnecessary in most cases. [ABSTRACT FROM AUTHOR]

The wave field created by a pulsed point source of sound in a uniform homogeneous flow with an arbitrary value of the Mach number is theoretically studied. The aim of research is to obtain an analytical dependence of the sound field on physical parameters. The space-waveguide Fourier expansion of the sound field is used to solve the Cauchy problem for the wave equation in a reference frame moving together with the medium. It is only necessary to transform the spatiotemporal dependence of the source, given in a fixed frame of reference, to a dependence in a moving frame of reference. The transition to the description of the solution in the frame of reference, relative to which the medium moves at a constant velocity, is made taking into account the main properties of the generalized Dirac d-function. Analytical dependences of the sound field on physical parameters are obtained for both subsonic and supersonic flows. A comparison is made with the results of calculations for the case of a pulsed point source moving in a medium at rest. The solution obtained in this work for the case of an impulsive source moving in a medium at rest made it possible to trace its connection with the Green's function for a stationary source in a moving medium. The analytical dependence of the obtained solution for the Green's function makes it possible to write down the explicit form of the «characteristic solution surface», that is, the «wave front». It is shown that the difference between the solutions for subsonic and supersonic motion is characterized by the position of the source relative to the moving wavefront. The calculation results can be used to describe the sound field created by an arbitrary spatiotemporal distribution of sound sources. [ABSTRACT FROM AUTHOR]

The spatial distribution of beams with orbital angular momentum in the far field is known to be extremely sensitive to angular aberrations, such as astigmatism, coma and trefoil. This poses a challenge for conventional beam optimization strategies when a homogeneous ring intensity is required for an application. We developed a novel approach for estimating the Zernike coefficients of low-order angular aberrations in the near field based solely on the analysis of the ring deformations in the far field. A fast, iterative reconstruction of the focal ring recreates the deformations and provides insight into the wavefront deformations in the near field without relying on conventional phase retrieval approaches. The output of our algorithm can be used to optimize the focal ring, as demonstrated experimentally at the 100 TW beamline at the Extreme Light Infrastructure - Nuclear Physics facility. [ABSTRACT FROM AUTHOR]

Reaction--diffusion waves in multiple spatial dimensions advance at a rate that strongly depends on the curvature of the wavefronts. These waves have important applications in many physical, ecological and biological systems. In this work, we analyse curvature dependences of travelling fronts in a single reaction--diffusion equation with general reaction term. We derive an exact, non-perturbative curvature dependence of the speed of travelling fronts that arises from transverse diffusion occurring parallel to the wavefront. Inward-propagating waves are characterized by three phases: an establishment phase dominated by initial and boundary conditions, a travelling-wave-like phase in which normal velocity matches standard results from singular perturbation theory and a dip-filling phase where the collision and interaction of fronts create additional curvature dependences to their progression rate. We analyse these behaviours and additional curvature dependences using a combination of asymptotic analyses and numerical simulations. [ABSTRACT FROM AUTHOR]

The results of atmospheric studies of the possibility of compensating for beam deviation from a given direction by means of shifting the energy center of gravity of the optical image formed by the beam of the scattering volume are presented. The atmospheric experiments were carried out with collimated and focused beams. The image of the laser spot on the scattering atmospheric layer was recorded by an array detector located in the sharp-image plane of a telescope. The laser beam propagation direction was controlled with a rotary mirror. It is shown that the beam deviation can be compensated with an accuracy to several microradians. [ABSTRACT FROM AUTHOR]

The variation in refractive index of the atmosphere causes wavefront aberration of optical signal propagating through the random atmosphere. This leads to various effects such as beam spreading, wandering and scintillation (intensity fluctuation) which are responsible for severe signal degrading of the free space optical (FSO) communication system. Incorporation of adaptive optics (AO) technique mitigates the effect of wavefront aberration distortions and reducing the signal fading. Non-conventional adaptive optics is demonstrated using complex search algorithms which requires large number of iterations and computations to obtain the optimum value of the results. In this paper, Convolutional Neural Networks (CNN)-based novel wavefront aberration compensation technique is proposed. The aim of this work is to experience and validate the CNN-based wavefront sensorless adaptive optics (WFSLess AO) technique for 70 m realtime FSOC. The major issues such as time-consuming iterative processes and latency in complex search algorithms and similar algorithms are greatly avoided by detecting the wavefront distortion from the direct images of the optical beam used in the experimentation. LeNet CNN architecture is realized to compensate wavefront distortion for the acquired data sample under different weather condition. Experiments are conducted on Xilinx Spartan-6 FPGA using high level synthesis. The performance of the proposed scheme is compared to existing approaches (T Weyrauch and MA Verontsov in Appl. Opt. 44:6388–6401, 2005; MJ Booth in Opt. Express 14:1339–1352, 2006; H Linhai and R Changhui in Opt. Express 19:371–379, 2011) and it shows an effective Strehl Ratio, Root Mean Square and reduced computation time thereby resolves the latency issue while maintaining accuracy which is a serious problem in AO systems. [ABSTRACT FROM AUTHOR]

• The field of mutiparameter sensing elements is explored via tailoring the response of optical wavefronts. • Conventional & digital holographic platforms along with metamaterials are employed to address the developments in the simultaneous multiparameteric sensors. • Such endeavors can envision the interleaving of multiple devices on a single chip for interdisciplinary pursuits. Optical sensors play an important role in advancing science and technology for improving the standard of living. These sensors work by accessing the alteration in one or more parameters of the optical beam such as phase, intensity, polarization, wavelength, wavefront, etc. through interaction with the test sample. The precise control of an optical wavefront has become important to achieve key functionalities of the optical sensors. Holography is one of the important and easy approaches to controlling and studying the wavefronts. Using this strategy, the wavefront can be examined both through the photographic recording-based conventional holography and through digital holography. Holography-based techniques are being used widely for sensing and imaging applications. Conventional holography-based sensors work by detecting either a change in the diffraction efficiency of the hologram or the wavelength of the beam. Further, digital holography-based sensors detect changes in the phase of the beam. In recent times, metamaterials are emerging as novel materials for many applications including sensing. Metamaterials are artificial subwavelength inclusions structured ingeniously as a potential substitute for materials available in nature. They stimulate an additional degree of freedom by breaking fetters laid by traditional designs to conduct multivariate analysis. This is an infant discipline that can envision the interleaving of multiple devices on a single chip and guide sensing developments of interdisciplinary pursuits. The present work encompasses a comprehensive outlook on optical sensors based on wavefront modulation using holographic and metamaterial-based approaches. [ABSTRACT FROM AUTHOR]

The spatial distribution of beams with orbital angular momentum in the far field is known to be extremely sensitive to angular aberrations, such as astigmatism, coma and trefoil. This poses a challenge for conventional beam optimization strategies when a homogeneous ring intensity is required for an application. We developed a novel approach for estimating the Zernike coefficients of low-order angular aberrations in the near field based solely on the analysis of the ring deformations in the far field. A fast, iterative reconstruction of the focal ring recreates the deformations and provides insight into the wavefront deformations in the near field without relying on conventional phase retrieval approaches. The output of our algorithm can be used to optimize the focal ring, as demonstrated experimentally at the 100 TW beamline at the Extreme Light Infrastructure - Nuclear Physics facility.

We developed and implemented an experimental setup for the generation of high-energy high-order harmonics in argon gas for nonlinear experiments in the extreme ultraviolet (XUV) spectral range. High-order harmonics were generated by loosely focusing a high-energy laser pulse centered around 800 nm into a gas cell filled with argon in a phase-matching condition. The wavefront distortions of the driving pulse were corrected by a deformable mirror, and the XUV conversion efficiency was significantly improved due to the excellent beam profile at focus. A high-damage-threshold beam splitter was used to eliminate high-energy driving pulses co-propagating with high-order harmonics. The setup has a potential to provide intense ultrashort XUV pulses reaching the intensity levels required for nonlinear experiments in the XUV spectral range.

In the geometrical optics approximation, we consider a method for calculating a refractive optical element with two freeform surfaces, which transforms an incident beam with a plane wave-front into an output beam with a required wavefront and generating a required illuminance distribution. As examples, optical elements forming given illuminance distributions and (converging and diverging) spherical wavefronts are designed. The presented examples demonstrate the good performance of the method.

Introduction: To compare intrasession agreement and repeatability of wavefront aberration measurements from three different aberrometers obtained using Hartmann–Shack, ray tracing and automated retinoscopy methods, as well as their interdevice agreement. Methods: Three consecutive measurements were obtained using the Pentacam AXL Wave, the iTrace and the OPD‐Scan III in 47 eyes of 47 patients. Wavefront refractions, root mean square of total aberrations (RMS total), RMS of higher‐order aberrations (HOA) and second‐, third‐ and fourth‐order HOAs were exported for 4‐mm pupils. Wavefront refractions were converted into vector components: M, J0 and J45. Intrasession agreement and repeatability were evaluated using intraclass correlation coefficients (ICCs) and repeatability coefficients (RCs); interdevice agreement was assessed using the Bland–Altman method. Results: The intrasession agreement and repeatability of RMS HOA were comparable between the three devices; both the Pentacam AXL Wave and the OPD‐Scan III had better intrasession agreement and repeatability for the RMS total than the iTrace (p ≤ 0.02). Intrasession repeatability for the majority of second‐ and third‐order aberrations was better on the Pentacam AXL Wave than on the iTrace (p ≤ 0.01) and OPD‐Scan III (p ≤ 0.04), although their agreement and repeatability in spherical aberration were comparable (p ≥ 0.24). Significant systematic differences and proportional bias were detected for almost all refraction power vectors and Zernike coefficients among the three devices. Conclusions: In this study, all three devices provided good‐to‐excellent agreement for aberration measurements. Most of the individual Zernike's components were not exchangeable between different aberrometers. Their relative intrasession performance in agreement and repeatability varied significantly across different ocular aberration parameters. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to analyze the objective optical properties of 2 enhanced depth of focus (EDoF) intraocular lenses (IOLs) using optical bench analysis. Methods: This experimental study investigates 2 new EDoF IOLs, the Alcon AcrySof IQ Vivity and the Bausch & Lomb LuxSmart Crystal, on the optical bench, using OptiSpheric IOL PRO2 (Trioptics, Germany) in order to assess the optical quality according to ISO 11979 with ISO-2 Cornea. IOLs (power 22.0 D) were evaluated regarding modulation transfer function (MTF) at 50 lp/mm and Strehl ratio (SR) using a 3.0-mm and a 4.5-mm aperture. In addition, wavefront measurements were obtained using WaveMaster® IOL 2 device (Trioptics, Germany), and USAF targets were analyzed. Results: Centered: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.250/0.257 and with 4.5 mm aperture 0.202/0.243. The SR (mean) with 3.0 mm aperture was 0.261/0.355 and with 4.5 mm aperture 0.176/0.206. Decentered by 1 mm: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.266/0.247 and with 4.5 mm aperture 0.126/0.215. The SR (mean) with 3.0 mm aperture was 0.272/0.234 and with 4.5 mm aperture 0.133/0.183. Tilted by 5 degree: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.221/0.360 and with 4.5 mm aperture 0.214/0.229. The SR (mean) with 3.0 mm aperture was 0.232/0.428 and with 4.5 mm aperture 0.225/0.229. The simulated visual function using USAF test targets showed corresponding qualitative results. Wavefront measurements proved a complex optical design. Higher order aberrations in the central part of the optics were modulated up to the 10th order to enhance the range of functional vision to near distance, leaving the peripheral parts of the optics aberration free or as aberration correcting. Conclusion: The diversity of EDOF IOLs, their optics, and their respective impact on the vision quality must be understood in order to select the appropriate IOL in each individual case. This analysis of new, innovative IOL optics based on increased negative spherical aberration may help the ophthalmic surgeon to select the IOL which meets the individual requirements of the patient for best postoperative outcomes. It seems that there is no perfect IOL that is equally suitable for all patients, but the right choice is an individual, customized approach dealing with patients’ expectations.

In this paper, a novel method for the manipulation of linearly polarized (LP) electromagnetic waves using Pancharatnamâ€"Berry phase is proposed. By combining polarization synthesis and aperture phase distributions, the polarization angle and wavefront of an LP wave can be arbitrarily manipulated. Four metasurfaces were designed and fabricated to generate pencil, vortex, and Bessel beams with different polarization angels, respectively. Simulation and measurement results consist well and demonstrate the proposed method in both polarization and wavefront manipulation. [ABSTRACT FROM AUTHOR]

With the evolution of electronic devices, such as 3D cameras, addressing the challenges of text localization in 3D video (e.g., for indexing) is increasingly drawing the attention of the multimedia and video processing community. Existing methods focus on 2D video and their performance in the presence of the challenges in 3D video, such as shadow areas associated with text and irregularly sized and shaped text, degrades. This paper proposes the first approach that successfully addresses the challenges of 3D video in addition to those of 2D. It employs a number of innovations, among which, the first is the Generalized Gradient Vector Flow (GGVF) for dominant points detection. The second is the Wavefront concept for text candidate point detection from those dominant points. In addition, an Adaptive B-Spline Polygon Curve Network (ABS-Net) is proposed for accurate text localization in 3D videos by constructing tight fitting bounding polygons using text candidate points. Extensive experiments on custom (3D video) and standard datasets (2D video and scene text) show that the proposed method is practical and useful, and overall outperforms existing state-of-the-art methods. [ABSTRACT FROM AUTHOR]

• Determining the equations of wavefronts and wave rays by Randers geodesics. • Providing the model of wildfire propagation by Huygens' principle. • Determining the paths through them the fire reaches a special place. • Determining the paths through which the fire spreads faster. Here, by using the validity of the Huygens' envelope principle for wavefronts in Randers spaces, we present some models for wildfire propagation in a flat land under the presence of wind. The wind could be constant or space-dependent. In the models, the height of the propagation is considered, trajectories of fire particles are tracked, and the equations that give the wavefront at each time are provided. Furthermore, we determine the paths of great importance in the process of wildfire management, called strategic paths. These paths can be used to determine the locations of barriers that we make to block the fire and stop it from propagation toward some special area; or to determine the paths through which the fire surrounds, for instance, the transmission lines of the power system. Finally, we provide several interesting examples of spreading the wildfire with different conditions. We implement the examples in the MATLAB environment to solve and provide the models of fire propagations. [ABSTRACT FROM AUTHOR]

The results are presented of atmospheric experiments on compensation for the artificially introduced initial aberrations of the wavefront of a focused laser beam using the aperture sounding method based on an atmospheric backscatter signal from an additional source at a different wavelength. It is shown that adaptive compensation can reduce wavefront distortions, increase the backscatter signal, and restore the focusing of the main laser beam. [ABSTRACT FROM AUTHOR]

We analyze the multiconjugate adaptive-optics (MCAO) systems and identify the specific features of the conjugation of adaptive mirrors with turbulent layers for ground-based solar telescopes. The optimal size of the field of view for a solar telescope operating under average atmospheric conditions is calculated to be 10 arcsec. Recommendations are given for the development of MCAO systems for ground-based solar telescopes. We suggested the concept of a system for determining 3D wavefront distortions for the Large Solar Telescope LST-3, as well as for the contour of recording phase distortions in the Large Solar Vacuum Telescope. [ABSTRACT FROM AUTHOR]

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights 1. The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. 2. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. 3. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

• Laser-induced thermal effect phenomena under different buoyancy conditions are analyzed for dynamically rotating closed optical chambers. • Summarized the change rule of the wave front of the beam outgoing from the enclosed chamber. • Pointing out that beam propagation at low angles has superior wavefront output. With the Boussinesq approximation of incompressible Navier-Stokes equations, the temperature distribution introduced by natural convection due to buoyancy is analyzed. Then ray optics is applied to calculate the changes of wavefront. For this system, characteristics of the temperature distribution and outlet wavefront are emphatically investigated on different propagation angle. It is found that the wavefront has a change rule of first rising, then decreasing, and then asymptotically converging within 60 s. Furthermore, the buoyancy will seriously affect the temperature distribution, thus affecting the wavefront and propagation at low angles has better output wavefront. [ABSTRACT FROM AUTHOR]

A method for generating solutions of the Burgers equation, which describe the interaction of waves in a nonlinear dissipative medium with a linearly growing wavefront, is proposed. The exact solutions describing these interactions and symmetry properties of the equation are used. It is shown that the rising wavefront is able to compete with the dissipation and compress the signal in time. On the contrary, the wavefront with the decreasing steepness "stretches" the signal. [ABSTRACT FROM AUTHOR]

The article focuses on the atrial fibrillation (AF) mapping technology called RETRO-Mapping, it analyzes activation patterns during AF using a multipolar catheter. It reports that the wavefront activation directions and demonstrates that activation patterns can predict subsequent wavefront patterns, providing insights into the complexities of AF activation patterns and potentially improving treatment approaches.

Angle sensors are widely used for wavefront measurements, which is attributed to their integration and robustness. Currently, commercial sensors are available with pixel sizes in the order of wavelengths. However, the spatial resolution of angle sensors still lags far behind. Here, we report a one-dimensional, high-resolution wavefront sensor. It was produced by introducing subwavelength compound gratings above the pixels. The gratings involved could be replaced by the sensor’s intrinsic readout circuitry without additional operation. The experimental results showed that it had a spatial resolution of 1.4 µm, two orders of magnitude higher than that of the Shack–Hartmann wavefront sensor. The significant increase in spatial resolution enables angle sensors to reconstruct complex wavefronts accurately.

Particulate polymer composites (PPCs) are widely applied under different elastic wave loading conditions in the automobile, aviation, and armor protection industries. This study investigates the elastic wave propagation behavior of a typical PPC, specifically a Cu/poly (methyl methacrylate) (PMMA) composite, with a wide range of particle contents (30–65 vol. %) and particle sizes (1–100 μm). The results demonstrate an inflection phenomenon in both the elastic wave velocity and attenuation coefficient with increasing volume content. In addition, the inflection point moves to the direction of low content with the increase in particle size. Notably, the elastic wave velocity, attenuation, and wavefront width significantly increased with the particle size. The inflection phenomenon of elastic wave propagation behavior in PPCs is demonstrated to have resulted from particle interaction using the classical scattering theory and finite element analysis. The particle interaction initially intensified and then reduced with increasing particle content. This study elucidates the underlying mechanism governing the elastic wave propagation behavior of high particle content PPCs and provides guidelines for the design and application of wave-absorbing composites.

The mobile localized deformation fronts formed in elastoplastic transition are considered for materials with dislocational and martensitic plastic flow mechanisms, in the case of active extension at different rates. The motion of the fronts is recorded and described on the basis of correlation methods for digital images. A synergetic approach is adopted. The deformed object is regarded as an open system that is far from equilibrium—that is, an active medium containing distributed potential-energy sources, which are stress microgenerators. Under external perturbation, these concentrators relax by microshear and the object is reshaped. Each microgenerator may be regarded as an active element with two states: metastable elastic stress; and a stable relaxed state. Under external perturbation, only transition from elastic stress to the relaxed state is possible. These are regarded as trigger elements; the active medium is characterized as bistable. In bistable media, switching autowaves are observed; these are mobile boundaries between the metastable and stable states. Within this framework, the localized deformation fronts may be interpreted as switching autowaves. It is found that the form and kinetic parameters of the localized deformation fronts do not depend on the chemical composition, structure, or micromechanisms of deformation; this confirms that they are autowaves. However, the kinetics of switching autowaves must be determined by the parameters of the external perturbation. In fact, the velocity of the localized deformation fronts increases with increase in the extension rate. It is established that the velocity of the localized deformation fronts depends nonlinearly (parabolically) on the strain rate. The exponent of this dependence is less than one and is the same for all the materials considered. [ABSTRACT FROM AUTHOR]