Three-dimensional imaging, complete with large fields of view and depth of field, combined with micrometer-scale resolution, is facilitated by in-line digital holographic microscopy (DHM), all within a compact, cost-effective, and stable system. We present the theoretical foundation and experimental verification of an in-line DHM system, employing a gradient-index (GRIN) rod lens. Moreover, we design a conventional in-line DHM employing pinholes with various arrangements, to analyze the resolution and image quality performance of GRIN-based and pinhole-based systems. Our optimized GRIN-based approach shows enhanced resolution (138m) within a high-magnification setting, achieved by placing the sample near a source of spherical waves. This microscope was employed for the purpose of holographically imaging dilute polystyrene microparticles, having diameters of 30 and 20 nanometers. Our study considered the effect of varying distances between the light source and the detector, and the sample and the detector, on resolution, through a combination of theoretical deduction and empirical testing. The results of our experiments perfectly match our theoretical estimations.

Inspired by the multifaceted nature of natural compound eyes, artificial optical devices are engineered for extensive visual coverage and rapid motion tracking. In contrast, the imaging within artificial compound eyes is strongly dictated by the function of numerous microlenses. The single focal length of the microlens array demonstrably reduces the applicability of artificial optical devices, hindering tasks like distinguishing objects placed at varying distances. An inkjet-printed, air-assisted, curved artificial compound eye, featuring a microlens array of varying focal lengths, was constructed in this study. The microlens array's inter-microlens spaces were altered, leading to the creation of additional microlenses situated between the original primary microlenses. The primary microlens array's diameter and height are 75 meters and 25 meters, while the secondary array's dimensions are 30 meters in diameter and 9 meters in height. Air-assisted deformation was instrumental in changing the planar-distributed microlens array to a curved configuration. Simplicity and ease of operation characterize the reported method, which contrasts with the alternative of adjusting the curved base to differentiate objects at diverse distances. The artificial compound eye's field of view is tunable via alterations in the applied air pressure. Without additional components, microlens arrays, each possessing a distinct focal length, allowed for the differentiation of objects positioned at disparate distances. Microlens arrays discern minute movements of external objects, owing to variations in focal length. Implementation of this method could yield a considerable advancement in the optical system's motion perception capabilities. Additionally, the fabricated artificial compound eye's imaging and focusing capabilities were thoroughly tested and assessed. The compound eye, a synthesis of monocular vision and compound eye structure, holds significant promise for the design of sophisticated optical instruments, characterized by extensive field of view and adaptable focusing mechanisms.

We have, through the successful implementation of the computer-to-film (CtF) process for computer-generated hologram (CGH) creation, developed, to the best of our knowledge, a new methodology for efficient and economical hologram manufacturing. This method facilitates the advancement of CtF processing and manufacturing, all thanks to innovative developments in hologram creation. In these techniques, the identical CGH calculations and prepress stages are applied to computer-to-plate, offset printing, and surface engraving. The presented approach, in conjunction with the previously mentioned techniques, possesses a substantial advantage in cost and scalability, creating a solid groundwork for their employment as security components.

The global environment is under serious threat from microplastic (MP) pollution, driving the creation of more sophisticated identification and characterization methods. Digital holography (DH), an innovative approach, provides a means for the detection of micro-particles (MPs) in a high-throughput flow system. This paper reviews the advancements in DH-assisted MP screening procedures. Our analysis of the problem incorporates both hardware and software perspectives. check details Automatic analysis, employing smart DH processing, reveals the significant contribution of artificial intelligence to classification and regression. Further examining this framework, the sustained development and prevalence of field-portable holographic flow cytometers for aquatic environments are also examined within the context of recent years' advancements.

Assessing the dimensions of each segment of the mantis shrimp is essential for determining the optimal form and architecture, and is pivotal in ideotype selection. Point clouds' efficiency has made them a popular solution in recent years. Nonetheless, the present manual measurement procedure is labor-intensive, expensive, and fraught with uncertainty. Automatic organ point cloud segmentation forms the basis and is a prerequisite for phenotypic measurements in mantis shrimps. In spite of this, few studies have examined the segmentation of mantis shrimp point clouds. For the purpose of filling this gap, this paper establishes a framework for automatic segmentation of mantis shrimp organs from multiview stereo (MVS) point clouds. In the initial stage, a Transformer-based multi-view stereo architecture is used to produce a dense point cloud from a selection of calibrated photographs from mobile phones and calculated camera parameters. The subsequent step involves the introduction of an improved point cloud segmentation technique, ShrimpSeg, which capitalizes on local and global features derived from contextual information for mantis shrimp organ segmentation. check details Based on the evaluation, the organ-level segmentation's per-class intersection over union measurement is 824%. Extensive experiments unequivocally demonstrate the effectiveness of ShrimpSeg, surpassing other commonly employed segmentation methods. Shrimp phenotyping and intelligent aquaculture practices at the production stage can potentially benefit from this work.

In the realm of high-quality spatial and spectral mode shaping, volume holographic elements stand out. Many applications in microscopy and laser-tissue interaction rely on the precise placement of optical energy at specific locations, with minimal effects on the surrounding tissues. The extreme energy contrast between the input and focal plane makes abrupt autofocusing (AAF) beams a good option for laser-tissue interaction processes. Within this work, we illustrate the recording and reconstruction methods of a volume holographic optical beam shaper fabricated from PQPMMA photopolymer material, intended for an AAF beam. The generated AAF beams are experimentally examined, exhibiting broadband operational behavior. The fabricated volume holographic beam shaper demonstrates consistent and high-quality optical performance over time. The advantages of our method include high angular selectivity, broadband functionality, and an intrinsically compact design. The present methodology may prove crucial in the development of compact optical beam shapers for diverse applications, including biomedical laser systems, microscopy illumination, optical trapping devices, and laser-tissue interaction investigations.

The task of reconstructing a scene's depth map from a computer-generated hologram, despite rising scholarly interest, continues to elude a solution. Employing depth-from-focus (DFF) methods, this paper seeks to recover depth information from the hologram. The hyperparameters required for this method and their subsequent influence on the final result are thoroughly investigated. Based on the findings, DFF methods permit depth estimation from holograms when the hyperparameter set is carefully calibrated, as evidenced by the results.

The paper demonstrates digital holographic imaging within a fog tube of 27 meters, filled with ultrasonically-generated fog. The ability of holography to image through scattering media is a consequence of its extraordinarily high sensitivity. Through extensive large-scale experiments, we evaluate holographic imaging's role in road traffic, which is crucial for autonomous vehicles requiring dependable environmental perception in all weather conditions. Single-shot, off-axis digital holography is evaluated and contrasted with conventional coherent imaging to demonstrate a 30-fold decrease in illumination power needed for comparable imaging coverage. Our work involves evaluating the signal-to-noise ratio, utilizing a simulation model, and generating quantitative conclusions about how different physical parameters affect the imaging range.

The fractional topological charge (TC) inherent in optical vortex beams has prompted significant interest due to its unique intensity distribution and distinctive fractional phase front characteristics in transverse planes. Among the potential applications are micro-particle manipulation, optical communication, quantum information processing, optical encryption, and optical imaging techniques. check details These applications necessitate an accurate knowledge of the orbital angular momentum, which is determined by the fractional TC of the beam. For this reason, the accurate measurement of fractional TC is a vital consideration. Employing a spiral interferometer and fork-shaped interference patterns, this study presents a simple method for determining the fractional topological charge (TC) of an optical vortex with a resolution of 0.005. We further illustrate the satisfactory performance of the proposed technique in situations of low to moderate atmospheric turbulence, a factor directly impacting free-space optical communication.

To maintain road safety for vehicles, the detection of tire defects plays a vital and indispensable role. Therefore, a rapid, non-invasive procedure is required for routinely evaluating tires in operation and for quality control of newly produced tires in the automotive industry.