The decay behavior of specific intensity is studied for spatial-frequency domain imaging (SFDI). It is shown using the radiative transport equation that the decay is given by a superposition of different decay modes, and the decay rates of these modes are determined by spatial frequencies and Case’s eigenvalues. This explains why SFDI can focus on shallow regions. The fact that light with nonzero spatial

This paper deals with the theory of primary aberrations for perturbed double-plane symmetric optical systems consisting of a combination of tilted and decentered surfaces and a circular pupil. First, the analytical expressions describing the full field behavior of Zernike polynomials are derived from the fourth-order wavefront aberration function for this class of optical systems. Then, such expressions

Laser scanners can be employed for spatial measuring tasks, but measuring accuracy is restricted because of the time of flight working principle. Laser-scanner-based observations with measuring errors might lead to rough spatial reconstruction. In this paper, an image registration method applying a Markov random field (MRF) algorithm is proposed. First, point cloud images are projected to a particular

We describe a generalized formalism, addressing the fundamental problem of reflection and transmission of complex optical waves at a plane dielectric interface. Our formalism involves the application of generalized operator matrices to the incident constituent plane-wave fields to obtain the reflected and transmitted fields. This formalism, though physically equivalent to Fresnel formalism, has greater

We demonstrate a type of singular beam that accelerates along a parabolic trajectory and has a cross-section intensity pattern exhibiting a dark central region surrounded by multiple rings with the innermost (main) ring resembling an equilateral triangle. The key to creating such beams is to replace the standard triangle with a rounded one, made up of six circular arcs connected end to end. The individual

Previous electromagnetic computations of multilayered dielectric/metallic spheres identified the ideal dimensions and composition for achieving optimized mass extinction coefficients (${{\rm{m}}^2}\!/{\rm{g}}$). A hollow metallic sphere, with a thin metallic shell, is one such example of a spherical structure that can theoretically achieve high mass extinction coefficients in the long wave infrared

We proposed a method for extracting the optical flow suitable for visualization, pseudo-flow (P-flow), from a natural movie [Exp. Brain Res. 237, 3321 (2019) [CrossRef] ]. The P-flow algorithm comprises two stages: (1) extraction of a local motion vector field from two successive frames and (2) tracking of vectors between two successive frame pairs. In this study, we show that while P-flow takes a

We use Mellin-transform techniques to derive generalized expressions for the piston-removed and piston-and-tilt-removed anisoplanatic error in non-Kolmogorov turbulence with a finite outer scale. We use these expressions to investigate the behavior of the anisoplanatic error when imaging over long horizontal paths where the angular extent of the scene is often many times the isoplanatic angle. By evaluating

The traditional Born series (TBS) and convergent Born series (CBS) methods to numerically solve the time-independent inhomogeneous photoacoustic (PA) wave equation are discussed. The performance of these algorithms is examined for a circular PA source (a disk of radius, $a = 5\,\,\unicode{x00B5}{\rm m}$) in two dimensions. The speed of sound within the source region was gradually decreased from ${v_s}

We present a novel acquisition scheme based on a dual-disperser architecture, which can reconstruct a hyperspectral datacube using many times fewer acquisitions than spectral bands. The reconstruction algorithm follows a quadratic regularization approach, based on the assumption that adjacent pixels in the scene share similar spectra, and, if they do not, this corresponds to an edge that is detectable

Monitoring strain is important in precision engineering applications that require maintaining the precise alignments of structures over time, such as those found in machine tools and metrology frames. We present a fiber-optic strain measurement technique based upon broadband interferometry that is variously configurable in terms of gauge length and sensitivity. This is achieved by the use of an unbalanced

A visual experiment using a beam-splitter-based optical see-through augmented reality (OST-AR) setup tested the effect of the size and alignment of AR overlays with a brightness-matching task using physical cubes. Results indicate that more luminance is required when AR overlays are oversized with respect to the cubes, showing that observers discount the AR overlay to a greater extent when it is more

Described over 100 years ago, the Gouy phase anomaly refers to the additional $\pi$ phase shift that is accumulated as a wave passes through focus. It is potentially useful in analyzing any type of phase-sensitive imaging; in light microscopy, digital holographic microscopy (DHM) provides phase information in the encoded hologram. One limitation of DHM is the weak contrast generated by many biological

This publisher’s note corrects the contents of references in J. Opt. Soc. Am. A 37, 1043 (2020) [CrossRef] .

This publisher’s note corrects the Fig. 6 caption in J. Opt. Soc. Am. A 37, C1 (2020) [CrossRef] .

Editor-in-Chief P. Scott Carney introduces the Journal’s newest Topical Editor, Arti Agrawal.

Africa has a long history in optics, but decades of turmoil have seen optical science in Africa advance only slowly, punching far below its weight. But a younger generation of scientists hold promise for the brighter future, addressing continental issues with photonics. In this Feature Issue on Optics in Africa we capture some of the exciting optical research from across the continent in 51 research

A quantitative analysis of optical fields is essential, particularly when the light is structured in some desired manner, or when there is perhaps an undesired structure that must be corrected for. A ubiquitous procedure in the optical community is that of optical mode projections—a modal analysis of light—for the unveiling of amplitude and phase information of a light field. When correctly performed

The distribution of optical turbulence ($C_n^2$ profiles) is the fundamental parameter closely related to the design and application of optoelectronic systems. Since systematic direct measurements of optical turbulence for many climates and seasons are not available, it is useful to estimate $C_n^2$ effectively from the routine meteorological parameters. The $C_n^2$ profiles are estimated by routine

Range (i.e., absolute distance), displacement, and velocity of a moving target have been measured with a frequency scanning interferometer that incorporates a ${100}{,}{000}\;{\rm scan}\;{{\rm s}^{- 1}}$ vertical-cavity surface-emitting laser with 100 nm tuning range. An adaptive delay line in the reference beam, consisting of a chain of switchable exponentially growing optical delays, reduced modulation

A frequency dependent differential photoacoustic cross-section (DPACS) over a large frequency band (100–1000 MHz) was computed, and subsequently, morphological parameters of a photoacoustic (PA) source were quantified. The Green’s function approach was utilized for calculating the DPACS for spheroidal droplets with varying aspect ratios, Chebyshev particles with different waviness and deformation parameters

The statistical properties of the polarization speckle produced by a random polarization phasor sum plus a constant polarization phasor are studied. Based on the Gaussian assumption for the random electric field, the three-dimensional joint probability density functions of the Stokes parameters and the parameters characterizing the polarization ellipse for the produced random polarization fields are

The method and corresponding optical scheme for the registration and reconstruction of digital volume holograms are considered. It is shown that a set of digital holograms recorded with a scanning reference beam makes it possible to reconstruct the complex amplitude of the object field. The proposed method for registering digital holograms is considered a digital analog of Denisyuk’s holography. In

We theoretically and experimentally study the propagation characteristics of elliptical Airy vortex beams (EAVBs) with a circular concentric vortex. It is found that EAVBs inherit the abruptly autofocusing properties of the circular Airy beams (CABs), but EAVBs will have a better autofocusing performance than circular Airy vortex beams (CAVBs) under certain conditions. It is also found that the initial

A numerical analysis of wave scattering by a body of revolution composed of a homogeneous dielectric sphere and an external inhomogeneous dielectric layer with arbitrary generatrix is carried out. A modification of the hybrid projection method developed in the paper includes expansion of the fields in terms of transverse vector spherical functions, projection of the Maxwell’s equations in the inhomogeneous

Three-dimensional quantitative phase imaging (3D QPI) is widely recognized as a potentially high-impact microscopic modality. Central to determining the resolution capability of 3D QPI is the phase optical transfer function (POTF). The magnitude of the POTF over its spatial frequency coverage (SFC) specifies the intensity of the response for each allowed spatial frequency. In this paper, a detailed

Time-domain diffuse optical tomography (TD-DOT) uses near-infrared pulsed lasers as light sources to measure time-varying exitance on the boundary of the target. These are used to estimate optical properties of the imaged target. Several integral-transform-based moments of the time-resolved data have been utilized in TD-DOT, the most common being the mean time of flight and variance. Recently, it has

We present a holographic imaging approach for the case in which a single source-detector pair is used to scan a sample. The source-detector pair collects intensity-only data at different frequencies and positions. By using an appropriate illumination strategy, we recover field cross correlations over different frequencies for each scan location. The problem is that these field cross correlations are

In this paper, we introduce a comprehensive study of the performance of intensity modulation (IM) techniques over gamma–gamma (GG) distributed free-space optical (FSO) channels. We derive closed-form expressions for the average bit error rate (BER) of thermal-noise-limited FSO systems adopting various IM techniques. The effect of atmospheric turbulence is studied. Comparisons are presented in terms

A contact-free inexpensive measurement system with an algorithm based on the integral form of video frames is proposed to estimate the respiration rate from an extracted respiration pattern. The proposed algorithm is applied and tested on 28 videos of sleeping-simulated positions, and the results are compared with the manual visual inspection values. With linear regression, the determination coefficient

Elastic properties of TaN films on (001)Si are investigated by surface Brillouin scattering (SBS). The velocity dispersion is obtained from Brillouin frequency shifts and surface acoustic wave phase velocities derived from measured SBS spectra. The observed Rayleigh surface acoustic and Sezawa waves indicate a soft on hard configuration. The elastic stiffnesses from the best fit of the calculated and

Phase-change materials are chalcogenide alloys used for nonvolatile memory applications due to their rapid and reversible structural transformation. ${{\rm In}_3}{{\rm SbTe}_2}$ is a promising candidate that exhibits transitions dependent on thermal conductivity. The minimum lattice thermal conductivity of amorphous ${{\rm In}_3}{{\rm SbTe}_2}$ is investigated by surface acoustic propagation. ${{\rm

Degree of paraxiality (DOP) of an anisotropic hollow multi-Gaussian Schell-model (HMGSM) beam is discussed, and the influence of parameters of the beam source on its DOP is studied. It is shown that the parameters of the beam source, including the anisotropy, boundary characteristic, beam waist width, and beam coherence width, may play an important role in its DOP. Moreover, in order to illustrate

Free-space propagation and experimental generation of a partially coherent radially polarized (PCRP) vortex beam were studied recently [Opt. Express 24, 13714 (2016) [CrossRef] ]. In this work, we explore the statistical properties of such a PCRP vortex beam propagating in a uniaxial crystal. We show that the anisotropy of the refractive index of the uniaxial crystal induces the asymmetrical distribution

Light spectra are a very important source of information for diverse classification problems, e.g., for discrimination of materials. To lower the cost of acquiring this information, multispectral cameras are used. Several techniques exist for estimating light spectra out of multispectral images by exploiting properties about the spectrum. Unfortunately, especially when capturing multispectral videos

A phase-retrieval algorithm can reconstruct the phase of an object from an intensity image of a diffraction pattern recorded at the Fourier plane, provided one makes a right initial guess. For the algorithms that are based on an initial random guess, at times, the output either becomes nondeterministic, becomes nonconvergent, or develops a twin image. For improving the performance of the algorithms

Diffraction calculations are widely used in applications that require numerical simulation of optical wave propagation. Different numerical diffraction calculation methods have their own transform and sampling properties. In this study, we provide a unified analysis where five popular fast diffraction calculation methods are analyzed from the perspective of phase space optics and the sampling theorem:

The emergence of the three-dimensional (3D) scanner has greatly benefited archeology, which can now store cultural heritage artifacts in computers and present them on the Internet. As many Terracotta Warriors have been predominantly found in fragments, the pre-processing of these fragments is very important. The raw point cloud of the fragments has lots of redundant points; it requires an excessively

Infrared imaging has been widely used in the field of sea surface monitoring. Horizon detection is a key step before a target’s detection, locating, and tracking in the sea–sky infrared scene. Reducing processing time while ensuring accuracy is the research focus of infrared horizon detection. This paper proposes a novel method of a line segment detector (LSD) algorithm with gradient direction filtering

We compare two analytical methods for designing stigmatic lenses that are based on very different paradigms published recently [Appl. Opt. 57, 9341 (2018) [CrossRef] ; J. Opt. Soc. Am. A 37, 1155 (2020) [CrossRef] ]. In the process, we derive a third hybrid approach, which is the result of combining the two original methods. Given the same initial conditions, an accurate numerical analysis shows that

Instrumentation design for Fourier transform spectroscopy has until now been hindered by a seemingly fundamental tradeoff between the étendue of the analyzed light source on one hand and the spectral resolution on the other. For example, if a freespace scanning Michelson interferometer is to achieve a spectral resolution of $4\;{{\rm cm}^{- {1}}}$, it can have a maximum angular field of view of roughly

This paper presents an approach to design the all-dielectric metasurface with multi-function in the near-infrared range of 1.5–1.6 µm. Based on the geometric phase principle, the all-dielectric metasurface is composed of the Si nanopillar and the ${\rm SiO}_2$ substrate as an emitter unit distributed in a ${21} \times {21}$ array. Under the incidence of the circularly polarized light at 1550 nm, the

We report on a theoretical and numerical study of a Gaussian beam modulated by several optical vortices (OV) that carry same-sign unity topological charge (TC) and are unevenly arranged on a circle. The TC of such a multi-vortex beam equals the sum of the TCs of all OVs. If the OVs are located evenly along an arbitrary-radius circle, a simple relationship for the normalized orbital angular momentum

Laser beam divergence was considered using the components of the Poynting vector. A physical interpretation of the real and imaginary parts of the “longitudinal” field component (along the $z$ axis, the direction of beam propagation) is given in an exponential representation. The longitudinal field component was shown to be the reason for the formation of laser beam divergence. This fact was used to

Color constancy algorithms are typically evaluated with a statistical analysis of the recovery angular error and the reproduction angular error between the estimated and ground truth illuminants. Such analysis provides information about only the magnitude of the errors, and not about their chromatic properties. We propose an Angle-Retaining Chromaticity diagram (ARC) for the visual analysis of the

We describe the details of an optical communication system using Gaussian vortex beams (GVBs). Our main focus will be on the detection strategy. The transmitter encodes the message symbols into the topological charges of the GVBs. Then the receiver implements a detection strategy based on the orthogonality of the GVBs. The graphical results obtained from the related theoretical derivation indicate

We introduce a partially coherent beam, called a multi-hyperbolic sine-correlated (MHSC) beam, by employing a multi-hyperbolic sine function to modulate the spectral degree of coherence. Based on the extended Huygens–Fresnel principle and second-order moments of the Wigner distribution function, we derive the analytical expressions for the spectral intensity, the root-mean-square (rms) angular width

The power spectrum of water optical turbulence is shown to vary with its average temperature $\langle T \rangle$ and average salinity concentration $\langle S \rangle$, as well as with light wavelength $\lambda$. This study explores such variations for $\langle T \rangle \in [{0{^ \circ}{\rm C},30{^ \circ}{\rm C}}]$, $\langle S \rangle \in [{0\;{\rm ppt},40\;{\rm ppt}}]$ covering most of the possible

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

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

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

The stripe of the tropical freshwater fish “neon tetra” consists of many iridophores, in which tilted reflecting platelets are periodically arranged. The neon tetra has structural coloration and changes the color of a stripe in response to the surrounding conditions. The mechanism of the color change is thought to be controlling a slant angle of the platelets and changing the spacing between the platelets

In a previous paper we described an accurate method for tracking a Gaussian beam incident on a particular diffraction grating. In this paper we use the same method to track a fundamental Gaussian beam at microwave frequency incident upon rectangular and sinusoidal gratings for more general information about the interaction during the process. We extensively study how different parameters of the incident

We call a surface that appears undistorted when viewed in a curved mirror an eigensurface and the mirror an eigenmirror. Such pairs are described by a first-order nonlinear partial differential equation of the form ${a_0} + {a_1}{u_x} \,+ {a_2}{u_y} + {a_3}{u_x}{u_y} + {a_4}u_x^2 + {a_5}u_y^2 = 0$, where ${a_i} = {a_i}(x,y,u)$, which we call the anti-eikonal equation. We give examples of symbolic and

A laboratory-prepared wedge-shaped fiber probe using step-index multimode plastic optical fiber was described and tested in a lab-scale gas–liquid flow generator. A three-dimensional model was established in order to fully simulate the process of bubble piercing by the optical fiber probe. A theoretical analysis of the luminous intensity distribution of the light transmission in the process of bubble

CMOS sensors employ a row-wise acquisition mechanism while imaging a scene, which can result in undesired motion artifacts known as rolling shutter (RS) distortions in the captured image. Existing single image RS rectification methods attempt to account for these distortions by using either algorithms tailored for a specific class of scenes that warrants information of intrinsic camera parameters or

The paper describes a method using digital image processing in the detection of vaguely defined visual defects on objects symmetric with respect to a rotation axis. Automotive wheels and hubcaps, fans, turbines, symmetrical ceramic goods, merchandise, etc., are examples of such objects. The method uses the object’s surface symmetry to identify areas that do not meet the requirement for the symmetry

Wave optics is usually thought to be more rigorous than geometrical optics to analyze integral imaging (II) systems. However, most of the previous wave-optics investigations are directed to a certain subsystem or do not sufficiently consider the finite aperture of microlens arrays (MLAs). Therefore, a diffraction-limited model of the entire II system, which consists of pickup, image processing, and

Adaptive optics (AO) is an established technique to measure and compensate for optical aberrations. One of its key components is the wavefront sensor (WFS), which is typically a Shack–Hartmann sensor (SH) capturing an image related to the aberrated wavefront. We propose an efficient implementation of the SH-WFS centroid extraction algorithm, tailored for edge computing. In the edge-computing paradigm

Modern Flash X-ray diffraction Imaging (FXI) acquires diffraction signals from single biomolecules at a high repetition rate from X-ray Free Electron Lasers (XFELs), easily obtaining millions of 2D diffraction patterns from a single experiment. Due to the stochastic nature of FXI experiments and the massive volumes of data, retrieving 3D electron densities from raw 2D diffraction patterns is a challenging