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

Vector beams with customizable topological charges hold significant potential for augmenting the capacity of optical communication systems. However, their propagation through random media like atmospheric turbulence induces wavefront distortion and intensity scintillation, severely degrading performance. To address this, we propose and design an inverse super-Gaussian non-uniformly correlated vector beam (ISGNCVB) with a tunable coherence structure. We thoroughly investigate its propagation characteristics in turbulent conditions. Our results demonstrate that the non-uniform correlation design confers remarkable self-focusing effects and stabilizes the received intensity profile. This leads to a signal-to-noise ratio (SNR) gain of up to 2 dB compared to its uniformly correlated counterpart. Furthermore, the polarization mode purity of the ISGNCVB exhibits enhanced robustness against turbulence-induced degradation. These advantages make the ISGNCVB a highly promising candidate for high-performance free-space optical communication links.

A comprehensive analysis of focal energy density is important in designing and improving the performance of any optical system that uses focused light beams. In this work, we propose a geometrical ray tracing-based scheme that can compute the energy densities or spot diagrams corresponding to different polarizations in the imaging plane due to any arbitrary user-defined beam. In our model, we incorporate lens-specific parameters such as radius of curvature, thickness, focal length, and refractive index, the spatial light modulator plane generating an arbitrary beam profile and 4f relay lens pairs, to trace both paraxial and skew rays up to the imaging plane through different refracting surfaces, providing a more realistic computational approach to obtain the focal spot. In particular, our model incorporates the vectorial nature of the light for each ray to facilitate computation of the vectorial spot diagrams, which are in effect a representation of the energy densities, corresponding to different orthogonal polarizations. We have implemented our model using the open-source programming language Python. The results using both low and high numerical aperture lenses indicate interesting similarities as well as distinctions in comparison with those obtained using vectorial diffraction theory.

We recently introduced adaptive Fresnel lenses (AFLs) based on complementary cylindrical lenses "bent into" spirals. Here, we start to investigate the wave optics of such components. We calculate typical point-spread functions and investigate diffraction effects in the case of narrow windings. We design a modification that results in the phase profile for light that passes through corresponding windings being that of a parabolic lens, exactly, but only in the case of infinitesimally thin phase components. Our findings contribute to the improvement and understanding of spiral AFLs.

The integration of space optical communication and fiber optical system plays a vital role in satellite communications and deep space exploration. However, achieving efficient fiber coupling under defocus conditions remains a key challenge. Consequently, a new, to our knowledge, aspheric shaping lens set composed of elliptical and hyperboloidal (E-H) surfaces is proposed in this study. This E-H lens set transforms the hollow beam emitted from the receiving end of a Cassegrain antenna into a solid beam, thereby reducing the loss of central energy inherent in hollow beam transmission. An optical system incorporating the Cassegrain antenna and the aspheric lens set is designed, with the lens surface equations derived based on the principle of equal optical path. Furthermore, considering chamfer design and Fresnel reflection loss, a new, to our knowledge, hyperbolic Fresnel (H-F) coupling lens is researched. This system achieves a coupling efficiency of 79.55% for a fiber mode field radius of 5 µm, with fiber defocus ranges of 2.36 µm (lateral offset), 68.34 µm (longitudinal offset), and 47.24 mrad (angular jitter). Importantly, within these defocus ranges, offsets of the optical fiber receiver do not cause a significant variation in the coupling efficiency of the optical communication system.

Optical cavities serve as powerful tools for sensing experiments, often relying on narrow-linewidth laser sources to minimize the impact of optical coherence on measurements. However, demands for affordable integrated and miniaturized sensing platforms in point-of-care diagnostics, environmental monitoring, and similar applications motivate switching to sources with broader linewidths suitable for both monolithic and heterogeneous integrations. Time-domain measurement techniques such as cavity ring-down spectroscopy (CRDS) are widely used in conjunction with optical cavities, but to date there has been no universal model that quantifies the impact of partial coherence on the cavity temporal transfer function. We apply a linear systems theory approach to develop a closed-form analytic model for cavity-based sensing that quantifies the influence of source bandwidth (i.e., temporal coherence) on spectroscopic measurements in the time domain. This approach can be applied to a variety of cavity-based spectroscopies. In this study, cavity-enhanced absorption spectroscopy (CEAS) and CRDS paradigms have been examined using standing- and traveling-wave resonator examples. Results show that although increased cavity loss is the primary factor reducing output power and photon lifetime in both CEAS and CRDS, broader source linewidths can also influence cavity buildup and transmission and must be accounted for when modeling the system response. The model is consistent with known results in the literature and provides a framework for evaluating source detuning and coherence effects on cavity dynamics.

Optical wave propagation through oceanic turbulence suffers from phase and amplitude distortions caused by refractive-index fluctuations due to temperature and salinity random variations in seawater. The split-step method has been widely employed for numerical simulation of light propagation in turbulent media, where the propagation path is discretized into multiple segments. This discretization ensures that each segment is sufficiently short such that refractive-index variations induce only phase distortions without affecting the amplitude. A critical component of this method involves accurate generation of thin phase screens (PSs) based on the refractive-index spatial power-law spectrum (RISPS). This study utilizes the general oceanic turbulence RISPS to create PSs. We show that optimal accuracy requires a hybrid implementation combining PWD (proposed by Paulson, Wu, and Davis) frequency-domain approach with Zernike polynomial-based spatial-domain decomposition.

Two complementary cylindrical lenses, each bent into a spiral, can form the components of an adaptive Fresnel lens whose focusing power can be tuned by rotating the two components relative to each other [Armstrong et al., J. Opt. Soc. Am. A42, 211 (2025)JOAOD60740-323210.1364/JOSAA.540585]. Corresponding windings of the cylindrical-lens spirals form the windings of the resulting adaptive Fresnel lens, and the addition of an Alvarez-Lohmann lens to the cylindrical lenses can improve the device through winding focusing-ensuring that each winding has the same focusing power as the Fresnel lens. Here we extend the type of spiral from logarithmic to Archimedean and hyperbolic; we introduce an alternative type of winding focusing by varying the separation between the two components; and we show how to design our adaptive Fresnel lenses so that, unlike the original design, they work best around non-zero focusing power. Finally, we present SpiralFresnelFrenzy, a web app that allows interactive and immersive raytracing simulations of the view through adaptive Fresnel lenses using augmented reality (AR) or virtual reality (VR). Our work significantly generalizes and improves spiral adaptive Fresnel lenses.

Convolutional neural networks (CNNs), widely employed in image recognition, show significant promise in identifying topological charges of vortex beams. Elliptical Airy vortex beams (EAVBs) introduce an additional elliptical parameter t, expand the dimensionality of Airy vortex beams, and thus offer an opportunity to increase the capacity for orbital angular momentum communication. In this work, we develop a compact CNN architecture to classify key parameters of EAVBs: the topological charge m and the elliptical parameter t. Trained on physics-augmented datasets that combine simulated and experimental autofocusing intensity patterns, the network achieves over 99.80% accuracy on a standard test set across three independent training runs. Its robustness is further validated on a set of unseen experimental patterns: it accurately recognizes all unaugmented new patterns and maintains consistent performance (98.24%-100%) on augmented variations. These results lay the groundwork for EAVB-based optical communications enhanced by machine learning, providing large capacity and high dimensionality to meet growing bandwidth requirements.

A new, to our knowledge, design method for panoramic reflective infrared systems is proposed using dynamic curvature compensation and gradient descent to improve image irradiance uniformity. By combining ray tracing and multi-parameter analysis, the reflective surface is replaced with segmented arcs, and the design is iteratively expanded. This concise and effective method achieves 99.19% irradiance uniformity with accuracy five times higher than traditional methods. The design time is only 0.17 s, and one-step forming eliminates the need for secondary optimization, greatly simplifying the system design process. This provides new ideas for high-resolution, wide-field infrared imaging system design.

The application of vortex beams in optical communications is significantly constrained by wavefront distortions caused by atmospheric turbulence and system-induced aberrations. In high-energy laser systems, spherical and coma aberrations are commonly introduced due to thermal effects during manufacturing or beam propagation. To address the challenge of topological charge identification under such complex distortions, this paper proposes an enhanced IResNet18 model capable of simultaneously predicting the topological charge, spherical aberration coefficient, and coma aberration coefficient from distorted intensity patterns. Three experimental configurations are designed: vortex beams with spherical aberration, vortex beams with coma aberration, and vortex beams with combined spherical and coma aberrations. This study systematically investigates the impact of varying propagation distances and turbulence intensities on model performance. Results demonstrate that the proposed model achieves superior accuracy and training efficiency compared to existing models. These findings provide a robust framework for aberration-aware vortex beam recognition and offer valuable insights for enhancing the reliability of free-space optical communication systems.