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

We investigate the pair correlation function of the random phase component of light waves propagating through turbulent media. Specifically, we focus on the correlation function of phase gradients, considering the case of Gaussian initial profiles, with special attention paid to plane and spherical waves. The calculations are carried out within the framework of the principal order of perturbation theory.

In order to evaluate the far-field encircled radius of Gaussian beam propagation, we construct the scaling law from both theoretical and numerical aspects. First, we derived the theoretical formula of the far-field encircled radius for aperture-truncated Gaussian beams at different encircled power ratios. Then, the scaling law based on a theoretical formula considering jitter and aberration effects is further proposed. Finally, the scaling law is validated against wave-optics simulations. The results show that the scaling law we proposed can effectively predict the far-field encircled radius of Gaussian beams under different effects. It is hoped that the result can provide researchers and engineers with a predictive tool for laser applications ranging from laser systems to directed energy technologies.

Designing an optical aerial imaging system with high resolution and large fields of view (FoV) is a longstanding problem in remote sensing, astronomical observation, and geological exploration. In this paper, we propose a light field-guided optical synthetic aperture imaging system on master-slave unmanned aerial vehicles (UAVs). This system consists of single-master UAV and multiple-slave UAVs to capture cross-scale multiview aerial images to stitch an aerial image and even a video with high resolution and large FoV. However, relative poses of UAVs change dynamically during the flight, which causes the inaccuracy of large-FoV image stitching. To address this problem, we convert image stitching as a novel-view synthesis problem on a large-FoV light field. Under this insight, we construct a 5D light field to cover FoVs of all slave UAVs via Gaussian splatting technique. Then we exploit a light field-guided synthetic aperture imaging scheme to generate the high-resolution image. Additionally, this scheme can be extended for large-FoV video generation. Experimental results on real-world scenes show that the proposed imaging system is capable of generating the accurate, large-FoV, high-resolution image sequences. Hence, we believe that this system has great potential in large-FoV high-resolution aerial imaging.

A novel, to our knowledge, photonic quasi-crystal fiber surface plasmon resonance methane sensor with high sensitivity is designed and analyzed. The dual eccentric-core D-shaped structure enhances the surface plasmon resonance effect. The groove is fabricated on the D-shaped surface, and then zinc oxide and gold films are sequentially deposited on the surface of the grooved structure. Finally, a methane-sensitive film is deposited. The effects of the structural parameters on the sensing properties are analyzed by finite element analysis. The results show that the optimal sensitivity and average wavelength sensitivity are 140 nm/% and 71.43 nm/% for methane concentrations in the range of 0%-3.5%. Owing to its small size, high sensitivity, and real-time online monitoring capabilities, the sensor has significant commercial potential in methane leakage detection.

Full-space metasurfaces have attracted much interest due to their ability to simultaneously manipulate the reflection and transmission of incident waves. Manipulating multifunctional devices with greater degrees of freedom is an ongoing trend of development. The realization of full-space multi-channel holographic and its dynamic display in the terahertz region remains a challenge. In this paper, a two-resonator terahertz metasurface based on photosensitive silicon is proposed to achieve integrated reflective-transmissive functionality. The conjugate response of a unit structure consisting of two photosensitive silicon resonators is decoupled by introducing the propagation phase and the geometric phase. Four independent channels can be dynamically displayed simultaneously in full space at the same frequency, with their output modulated by both the polarization of the incident wave and the state of the photosensitive silicon. As an illustrative example, a four-channel dynamic display metasurface is designed to project three-bit polarization-encoded holographic images. In addition, by employing the convolution theorem and the generalized Snell's law, dynamic control of beam deflection and multi-beam generation is realized for four-channel holographic projections. This work not only proposes a generic strategy for realizing full-space multifunctional metasurfaces, but also has applications in miniaturized optical systems, high-capacity optical encryption and data storage.

This study quantifies the unintended changes in wavefront aberrations within a sample of commercial scleral lenses due to the re-blocking step in the patch-cutting method for manufacturing wavefront-guided scleral lenses. The wavefront aberrations for a sample of 15 sphero-cylindrical scleral lenses were measured (Measurement 1) using a wavefront sensor. The lenses were mounted (re-blocked) onto a lens mount, removed (de-blocked) from the lens mount, and again measured (Measurement 2). The lenses were measured a third time (Measurement 3) after a period of storage. The difference in wavefront aberrations between Measurements 1 and 2 served as a treatment condition, and the difference between Measurements 2 and 3 served as a control condition. This study demonstrated that re-blocking of commercial scleral lenses induces small but measurable changes in the aberration structure of the lenses that may be important once aberrations from all steps in the method are considered.

Arrayed vortex beams hold promise for optical imaging, trapping, and free-space communication. In this paper, we propose a method to generate array-focused vortex beams using composite spiral zone plate gratings, with emphasis on a cross-shaped vortex array. Unlike conventional techniques that often rely on complex systems and inflexible experimental structures, the proposed method is easy to reconstruct, flexible to program, and simple in structure. We used genetic algorithms to optimize the structure of the cross-shaped vortex array to achieve better performance in atmospheric turbulence propagation. Through simulations and experiments, we demonstrate that the cross-shaped vortex array exhibits superior stability. This design improves propagation robustness in free space, particularly for practical optical communication applications where turbulence resistance is crucial.

A partially coherent rectangular symmetric array beam for the light source of the laser display system is proposed. The speckle of the laser display system is simulated theoretically by using the angular spectrum method combined with the random phase screen, and the experimental results are given. It is found that unlike traditional lasers, with the increase of the brightness of the laser display system, the speckle contrast does not increase significantly, i.e., the image quality does not decline. The purpose of increasing the brightness of the laser display system without affecting the image quality is achieved by either increasing the number of arrays or increasing the output of laser. The array offset does not affect speckle contrast. Similar to the traditional partially coherent beam, the speckle of the laser display system can be effectively suppressed by reducing the spatial coherence of the partially coherent array beam while keeping the number of arrays unchanged. As a light source, partially coherent array beams provide a novel means to resolve the contradiction between the increase in brightness leading to an increase in speckle contrast and affecting imaging quality, which is different from the traditional methods, and will have a good application prospect in large-size laser display systems or outdoor laser display systems.

Visualization in the virtual image formed by dielectric microparticles has been shown to enable the distinction of objects that remain indistinguishable under direct observation. We perform the resolution analysis based on a full two-dimensional simulation in the TE mode of optical image formation, taking into account the diffraction of partially coherent light on the microparticle and the objects under study. The oscillating nature of optical resolution is demonstrated depending on the size of the microparticle. The presence of strong resonances is observed in both transmission and reflection modes. It is shown that as the size of the object decreases, the optical resolution tends to the classical limit. An analytical estimate for the resolution criterion is presented.

Atmospheric turbulence significantly affects the propagation of light beams, which in turn impacts the quality of optical communication systems. However, the autofocusing beam is helpful in improving the propagation stability, resulting in better optical communication performance. In this paper, we have investigated the propagation characteristics of a ring Airy vortex beam (RAVB) and a ring Airyprime vortex beam (RAPVB) using a multiple random phase screens model, and the communication performance is a main focus of study, including orbital angular momentum crosstalk, channel capacity, and bit error rate. Quantitative analysis under moderate turbulence reveals that RAVB maintains a mode purity of 89.5% compared with 79.9% for RAPVB. The influences of atmospheric turbulence on the propagation stability and communication performance are discussed, and our results demonstrate that RAVB offers better performance than RAPVB under turbulent conditions. This work provides a pioneering comparative analysis of RAVB and RAPVB, offering valuable insights and tools for improving optical communication in turbulent environments.