Journal of The Optical Society of America A-optics Image Science and Vision最新文献

The determination of the minimum diopter correction requirements for XR systems is a critical task that necessitates a rigorous, evidence-based approach. This report offers recommendations for XR optical designers to identify the necessary diopter modulation for the target user population. The Weibull distribution is employed to model the refractive error distributions for these groups. The feasibility of this method in addressing high-order visual aberrations has been demonstrated. Comparisons are made among three demonstrated different populations (the United States, Europe, and China) to illustrate the minimum diopter requirements needed to accommodate various percentages of the population. The results of the study reveal that approximately 6 diopters are required to cover 90% of the general populations in both the United States and Europe. In contrast, the younger population in China requires an 8-diopter correction to achieve the same coverage percentage. This study not only underscores the utility of Weibull distribution in modeling refractive errors across different regional populations but also provides a compelling, evidence-based rationale for XR designers regarding the necessity of accommodating optics.

Soft x-ray wafer-metrology experiments are characterized by low signal-to-noise ratios and lack phase information, which both cause difficulties with the accurate three-dimensional profiling of small geometrical features of structures on a wafer. To this end, we extend an existing phase-based inverse-scattering method to demonstrate a sub-nanometer and noise-robust reconstruction of the targets by synthetic soft x-ray scatterometry experiments. The targets are modeled as three-dimensional finite dielectric scatterers embedded in a planarly layered medium, where a scatterer's geometry and spatial permittivity distribution are described by a uniform polygonal cross section along its height. Each cross section is continuously parametrized by its vertices and homogeneous permittivity. The combination of this parametrization of the scatterers and the employed Gabor frames ensures that the underlying linear system of the spatial spectral Maxwell solver is continuously differentiable with respect to the parameters for phaseless inverse-scattering problems. In synthetic demonstrations, we demonstrate the accurate and noise-robust reconstruction of the parameters without any regularization term. Most of the vertex parameters are retrieved with an error of less than λ/13 with λ=13.5n m, when the ideal sensor model with shot noise detects at least five photons per sensor pixel. This corresponds to a signal-to-noise ratio of 3.5 dB. These vertex parameters are retrieved with an accuracy of λ/90 when the signal-to-noise ratio is increased to 10 dB, or approximately 100 photons per pixel. The material parameters are retrieved with errors ranging from 0.05% to 5% for signal-to-noise ratios between 10 dB and 3.5 dB.

We provide a general description of the measurement capabilities of systems that probe the 3D state of polarization of light emitted by a dipole or a collection of dipoles. This analysis is based on a generalization of the Stokes parameters for 3D polarization, and its goal is to provide insight into what constitutes a good measurement system under specific circumstances, through the definition of appropriate merit functions. Three cases are considered: the general case of arbitrary states of 3D polarization, the special case of 3D linear full or partial polarization states, and the even more specific case of linear dipoles that wobble with rotational symmetry around a central direction. Note that the latter two cases are of interest in fluorescence microscopy. The analysis presented here is illustrated by applying it to two different approaches used commonly in orientation microscopy: PSF engineering and ratiometric measurements.

The perfect vortex beam, with a diameter that remains independent of the topological charge, has numerous applications in far-field information propagation. In this study, a hologram is obtained through the co-spiral superposition of two primary spiral axicons which is assigned to spatial light modulator for the generation of perfect vortex beams. Key parameters such as the topological charge and intra-ring spacing of individual spiral axicons play critical roles in controlling the characteristics of the resulting perfect vortex beam through the resultant hologram. By adjusting these parameters, precise control can be exerted over the number of openings in the beam and the diameter of the central dark area of the beam. The generation of the entire family of vortex beams with both odd and even numbers of openings in both symmetrical and asymmetrical geometry of the vortex beam petals is presented in simulation and experiment. The perfect vortex beam reported here is characterized by its adjustable number of openings and controllable petal size, holding significant potential for applications in optical trapping. The existence of multiple circular vortex petals with different radii is expected to enable the optical sorting of different particles.

Quantitative phase imaging (QPI), propelled by advancements in digital holography and computational imaging, has revolutionized the ability to retrieve phase delays with high precision. Over the past two decades, the field has seen tremendous growth, contributing to numerous applications in biomedicine and material metrology, including live cell monitoring, material structure profiling, and defect inspection, among others. This special issue commemorates Prof. Gabriel "Gabi" Popescu, a former faculty member at the University of Illinois at Urbana-Champaign and a pioneer in QPI and label-free biological imaging, who passed away on June 16, 2022, in his hometown of Prundu, Romania. The issue honors Gabi's legacy with a collection of articles exploring QPI methodologies and their diverse applications.

Polychromatic digital holographic microscopy (P-DHM) has demonstrated its capacity to generate highly denoised optical path difference images, thereby enabling the label-free visualization of fine cellular structures, such as the dendritic arborization within neuronal cells in culture. So far, however, the sample must remain more or less stationary since P-DHM is performed manually, i.e., all actions are carried out sequentially over several minutes. In this paper, we propose fully automated, robust, and efficient management of the acquisition and reconstruction of the time series of polychromatic hologram sets, transforming P-DHM into temporal P-DHM. Experimental results have demonstrated the ability of the proposed temporal P-DHM implementation to non-invasively and quantitatively reveal the fine structure and dynamics of living cells.

Fourier ptychographic microscopy (FPM) technology combines the concepts of synthetic aperture imaging, ptychography, and phase retrieval to address the contradiction between the large field of view and high resolution in traditional microscopy and can achieve high-resolution amplitude and phase images with a large field of view. However, for most samples, the primary information is concentrated in the low-frequency region, and traditional single-height FPM may suffer from insufficient sampling, leading to low reconstruction accuracy. In addition, the reconstruction process typically requires a large number of low-resolution images, which also significantly reduces the reconstruction efficiency. To overcome these issues, this paper proposes a form of FPM with multi-height illumination based on an energy threshold pre-search. This method simply involves moving the LED array to three planes for multi-height sample illumination on the traditional FPM hardware, thus improving the sampling conditions and enhancing the reconstruction accuracy. The low-resolution images acquired in this way are then screened using an energy threshold method to select images with higher energy, and a phase retrieval method is employed to reconstruct high-resolution complex amplitude images. The results of simulations and experiments demonstrate that compared to traditional methods, our approach not only improves the reconstruction accuracy but also reduces the number of low-resolution images by at least approximately 60%, thereby significantly enhancing the reconstruction efficiency.

The diffraction of the so-called nondiffracting Bessel beam by an impedance disc immersed in an anisotropic medium is examined. The external uniform magnetic field, which makes the plasma anisotropic, is taken to be rotational as opposed to being parallel to the edge of the problem geometries in the literature. Thus, the appropriate dielectric matrix that models the anisotropic region under the rotational dc external magnetic field is derived for the first time, to the best of our knowledge. Upon considering the geometric optics waves, the total scattered waves are obtained with the diffracted waves by using the definition of high-frequency asymptotic expressions associated with the scattered waves at the transition regions. The results are expressed in terms of the Fresnel functions so that the wave behaviors in the transition regions are uniform. The solutions are compared numerically with existing studies in the literature, including limit values.

Dynamic fluorescence molecular tomography (DFMT) is a promising imaging method that can furnish three-dimensional information regarding the absorption, distribution, and excretion of fluorescent probes in organisms. Achieving precise dynamic fluorescence images is the linchpin for realizing high-resolution, high-sensitivity, and high-precision tomography. Traditional preprocessing methods for dynamic fluorescence images often face challenges due to the non-specificity of fluorescent probes in living organisms, requiring complex imaging systems or biological interventions. These methods can result in significant processing errors, negatively impacting the imaging accuracy of DFMT. In this study, we present, a novel, to the best of our knowledge, strategy based on the spatiotemporal Gaussian mixture model (STGMM) for the processing of dynamic fluorescence images. The STGMM is primarily divided into four components: dataset construction, time domain prior information, spatial Gaussian fitting with time prior, and fluorescence separation. Numerical simulations and in vivo experimental results demonstrate that our proposed method significantly enhances image processing speed and accuracy compared to existing methods, especially when faced with fluorescence interference from other organs. Our research contributes to substantial reductions in time and processing complexity, providing robust support for dynamic imaging applications.

Atmospheric turbulence results in the degradation of performance in optical communications, with the scintillation phenomenon significantly influencing the optical link performance. Various physical parameters influence optical scintillation, such as the atmospheric refractive index structure constant, optical transmission distance, turbulence intensity, and anisotropy. In classical theoretical predictions, the anisotropic factor is often assumed to be constant over the long term. Nevertheless, anisotropic factors in real turbulence undergo temporal fluctuations, manifesting as a distribution. Consequently, it is imperative to examine the correlation between the distribution of anisotropic factors and the outcomes of scintillation. This study utilizes a semi-Gaussian distribution for sampling anisotropic factors and employs the non-Kolmogorov spectrum to develop scintillation theory for Gaussian beams in the transition region from weak to strong turbulence. The results indicate that the scintillation index may be higher than the theoretical prediction when considering the distribution of anisotropic factors in weak turbulence. Conversely, in strong turbulence, the scintillation index may be lower than the theoretical prediction, necessitating further judgment for moderate to strong turbulence.