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

By combining the improved properties of the Bessel modulated autofocusing beam [Phys. Rev. A104, 043524 (2021)PLRAAN1050-294710.1103/PhysRevA.104.043524] with the influence of the canonical optical vortex, we study the dynamical characteristics of tightly focused circularly polarized modulated autofocusing vortex beams (CPMAVBs) and their performance in trapping chiral nanoparticles. We find that the distributions of the beam's intensity and dynamical characteristics depend on the value of the topological charge carried by the beam. Moreover, CPMAVBs exhibit higher peak intensity and superior dynamical characteristics compared to the circularly polarized circular Airy vortex beam (CPCAVB), despite the attenuation of the optimized modulation of the Bessel function due to the presence of vortex. Building on these excellent properties, CPMAVB demonstrates greater radial optical force (transverse trapping potential) and azimuthal optical force (orbital rotation frequency) for trapping chiral nanoparticles compared to CPCAVB. We also discuss the effects of input power and particle radius on the manipulation capabilities of CPMAVB and CPCAVB. Our results provide insights into the dynamical characteristics of the CPMAVB and may open new possibilities for the optical manipulation of chiral particles using this structured beam.

JOSA A and JOSA B are archival journals that have preserved the heritage and served the community in the field of optics for the past 40 years. In line with the community's expansion and evolution over this time, the journals have regularly reinvented themselves while also keeping an eye on the future. This editorial celebrates the journals' ruby anniversary and introduces readers to some recent statistical data points and trends.

Lorentz algebra is a significant and elegant language in 2-D SAM-related polarization optics, and it also holds potential theoretical value in 3-D polarization optics. This paper focuses on developing a decomposed generalized Mueller matrix (GMM) model for 3-D polarization transformations through a Lorentz algebraic approach. We first present a comprehensive analysis and review of the 2-D polarization state (SoP) and polarization transformations, introducing the necessary algebraic representations and approaches. Then, we further develop the 3-D transformation theory and present a convenient decomposed 3-D transformation model, which exists in both generalized Jones matrices (GJMs) and GMM representations. For GMM, the generator matrices of all sub-transformations (r→-rotation, z→-rotation, and z→-boost) are clearly defined and discussed for the first time, to our knowledge. And their correctness is verified from commutative relations and GMM simulations. Additionally, another simulation is presented to illustrate the potential application of decomposed GMM in non-paraxial beams and polarized ray-optics.

The possibility of realizing time dilation and time reversal of events taking place in a scene by using the multiple-wavelengths range-gated active imaging (WRAI) principle in superimposed style was studied. Both temporal behaviors could be analyzed as a function of time since the WRAI principle allows different positions of the object in the image to be frozen at different moments according to the wavelengths. As the speed of the photons varies in the function of the refraction law of the crossed medium, different media were used to intervene in the time of the events recorded by the camera. Different wavelengths were used to select these media. By increasing the refractive index of the crossed medium as a function of time, the scene events arrived chronologically with an increasing delay compared to the events seen in the open, giving the impression of slowing down time. Similarly, by decreasing the refractive index of the crossed medium as a function of time, the scene events arrived chronologically in the opposite direction compared to the events seen in the open, giving the impression of going back in time. Experimental test results validated the theoretical part and the possibility of observing these different temporal behaviors with the multiple-wavelengths range-gated active imaging principle in superimposed style.

We undertake a computational study of the steady-state thermal blooming effect on a special class of partially coherent vector beams, called partially coherent radially polarized (PCRP) beams, propagating through the atmosphere. A computational propagation model that is based on a multi-phase screen method is established to simulate partially coherent vector beams. With the use of this model, the propagation properties of PCRP beams with different initial powers and spatial coherence widths are studied in detail, including average intensity distribution, r.m.s. beam width, and polarization. Our results unveil that PCRP beams can effectively reduce or overcome the negative effects caused by thermal blooming when the initial coherence width falls below a certain threshold. Further, it is shown that the spatial distribution of degree of polarization (DOP) is significantly affected by the thermal blooming during beam propagation, whereas the global DOP (integrating the DOP over a beam's cross-section) is not.

Synthetic dimensions have drawn intense recent attention in investigating higher-dimensional topological physics and offering additional degrees of freedom for manipulating light. It has been demonstrated that synthetic dimensions can help to concentrate light with different frequencies at different locations. Here, we show that synthetic dimensions can also route light from different incident directions. Our system consists of an interface formed by two different photonic crystals. A synthetic dimension ξ is introduced by shifting the termination position of the photonic crystal on the right-hand side of the interface. We identify a correspondence between ξ and the interface state such that light incident from a specific direction can be collected. Thus, routing incident light from different directions is achieved by designing an interface with a proper distribution of ξ. Traditionally, this goal is achieved with a standard 4f optical system using a convex lens, and our approach offers the possibility for such a capability within a few lattice sites of photonic crystals. Such an approach reduces the size of the system, making it easier for integration. Our work provides, to our knowledge, a new direction for routing light with different momentums and possibly contributes to applications such as lidar.

Solar noise, when it interferes with the received signal at the system receiver (Rx) of an optical wireless communication (OWC) system, degrades the system's performance. The detrimental effect of solar noise on OWC systems has been well established in the literature. This work experimentally demonstrates solar noise interference in the OWC system by pointing the system Rx in various orientations in air and water mediums, e.g., 0° (Rx pointing horizontally leftward), 45°, 90° (Rx pointing vertically downward), 135°, 180° (Rx pointing horizontally rightward), 225°, 270° (Rx pointing vertically upward), and 315°. The experimental outcomes depict the signal's noise content, spectral leakage, and roll-off rate variation at multiple Rx orientations. We also demonstrate the solar noise interference in transmitting an image through the outdoor underwater OWC link by pointing the system Rx in various orientations. Experimental demonstration confirms that the same OWC system never behaves identically in the presence of solar noise if the system Rx keeps changing its orientation during the maneuver.

In applications such as free-space optical communication, a signal is often recovered after propagation through a turbulent medium. In this setting, it is common to assume that limited information is known about the turbulent medium, such as a space- and time-averaged statistic (e.g., root-mean-square), but without information about the state of the spatial variations. It could be helpful to gain more information if the state of the turbulent medium can be characterized with the spatial variations and evolution in time described. Here, we propose to investigate the use of data assimilation techniques for this purpose. A computational setting is used with the paraxial wave equation, and the extended Kalman filter is used to conduct data assimilation using intensity measurements. To reduce computational cost, the evolution of the turbulent medium is modeled as a stochastic process. Following some past studies, the process has only a small number of Fourier wavelengths for spatial variations. The results show that the spatial and temporal variations of the medium are recovered accurately in many cases. In some time windows in some cases, the error is large for the recovery. Finally, we discuss the potential use of the spatial variation information for aiding the recovery of the transmitted signal or beam source.

The recovery of a complex-valued exit wavefront from its Fourier transform magnitude is challenging due to the stagnation problems associated with iterative phase retrieval algorithms. Among the various stagnation artifacts, the twin-image stagnation is the most difficult to address. The upright object and its inverted and complex-conjugated twin correspond to the identical Fourier magnitude data and hence appear simultaneously in the iterative solution. We show that the twin stagnation problem can be eliminated completely if a coherent beam with charge-1 vortex phase is used for illumination. Unlike the usual plane wave illumination case, a charge-1 vortex illumination intentionally introduces an isolated zero near the zero spatial frequency region, where maximal energy in the Fourier space is usually concentrated for most natural objects. The early iterations of iterative phase retrieval algorithms are observed to develop a clockwise or anti-clockwise vortex in the vicinity of this isolated zero. Once the Fourier transform of the solution latches onto a specific vortex profile in the neighborhood of this intentionally introduced intensity zero in early iterations, the solution quickly adjusts to the corresponding twin (upright or inverted) and further iterations are not observed to bring the other twin into the reconstruction. Our simulation studies with the well-known hybrid input-output (HIO) algorithm show that the solution always converges to one of the twins within a few hundred iterations when vortex phase illumination is used. Using a clockwise or anti-clockwise vortex phase as an initial guess is also seen to deterministically lead to a solution consisting of the corresponding twin. The resultant solution still has some faint residual artifacts that can be addressed via the recently introduced complexity guidance methodology. There is an additional vortex phase in the final solution that can simply be subtracted out to obtain the original test object. The near guaranteed convergence to a twin-stagnation-free solution with vortex illumination as described here is potentially valuable for deploying practical imaging systems that work based on the iterative phase retrieval algorithms.

The Bessel-Gauss beam (BGB) stands as a physically realizable beam extensively employed in applications such as micromanipulation and optical trapping. In these contexts, the assessment of beam shape coefficients (BSCs) becomes imperative. Previous research reveals that the BSCs of the BGBs obtained with different methods deviate from each other under certain circumstances. In this paper, the formulation of BSCs employs the radial quadrature method, and a comparative analysis is conducted with counterparts formulated using the angular spectrum decomposition and the finite series technique. Contributions stemming from evanescent waves and the situation of the BSC blowing-ups are discussed, offering a deep insight of pertinent BSC evaluation methods. The paper provides an alternative approach for calculating the BSCs of the BGBs.