2024

• Record 37 of
  
  Title:Differentiable design of a double-freeform lens with multi-level radial basis functions for extended source irradiance tailoring
  
  Author(s):Tang, Haisong; Li, Haoran; Feng, Zexin; Luo, Yi; Mao, Xianglong
  Source: OPTICA  Volume: 11  Issue: 5  DOI: 10.1364/OPTICA.520485  Published: 2024  
  Abstract:Freeform optics are key for generating prescribed illumination patterns from given sources, which are crucial for solidstate lighting and machine vision illumination. There is an increasing demand for compact freeform optics, which presents a substantial challenge for current design methods since the source dimensions must be considered. Most current extended-source design methods, although requiring profound knowledge of optics and mathematics, focus on the modest goal of obtaining uniform irradiance distributions. We address a more challenging design problem of generating an irradiance distribution of arbitrary shape through a double-freeform lens that can fully encompass the extended source. We propose a differentiable design method whose uniqueness lies in the representation of the double-freeform surfaces using multi-level spherical radial basis functions, which has a natural link to a multi-scale optimization technique. In addition, we employ a sequential unconstrained minimization technology complemented with Lagrange multipliers that add key feasibility constraints on lens shape and size. The proposed method is flexible, general, and efficient in designing highly compact freeform lenses for generating both simple and complex irradiance distributions, as demonstrated through the design examples. This could enable a universal solution to the extended-source design problem. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 2334-2536
  eISSN:
• Record 38 of
  
  Title:FPM-WSI: Fourier ptychographic whole slide imaging via feature-domain backdiffraction
  
  Author(s):Zhang, Shuhe; Wang, Aiye; Xu, Jinghao; Feng, Tianci; Zhou, Jinhua; Pan, An
  Source: OPTICA  Volume: 11  Issue: 5  DOI: 10.1364/OPTICA.517277  Published: 2024  
  Abstract:Fourier ptychographic microscopy (FPM) theoretically provides a solution to the trade-off between spatial resolution and field of view (FOV), and has promising prospects in digital pathology. However, block reconstruction and then stitching has become an unavoidable procedure for reconstruction of large FOV due to vignetting artifacts. This introduces digital stitching artifacts, as the existing image-domain optimization algorithms are highly sensitive to systematic errors. Such obstacles significantly impede the advancement and practical implementation of FPM, explaining why, despite a decade of development, FPM has not gained widespread recognition in the field of biomedicine. We report a feature-domain FPM (FD-FPM) based on the structure-aware forward model to realize stitching-free, full-FOV reconstruction. The loss function is uniquely formulated in the feature domain of images, which bypasses the troublesome vignetting effect and algorithmic vulnerability via feature-domain backdiffraction. Through massive simulations and experiments, we show that FD-FPM effectively eliminates vignetting artifacts for full-FOV reconstruction, and still achieves impressive reconstructions despite the presence of various systematic errors. We also found it has great potential in recovering the data with a lower spectrum overlapping rate, and in realizing digital refocusing without a prior defocus distance. With FD-FPM, we achieved full-color and high-throughput imaging (4.7 mm diameter FOV, 336 nm resolution in the blue channel) free of blocking-and-stitching procedures on a self-developed Fourier ptychographic microscopy whole slide imaging platform. The reported FD-FPM shows the value of FPM for various experimental circumstances, and offers physical insights useful for the developments of models for other computational imaging techniques. The reported platform demonstrates high-quality, high -speed imaging and low cost, and could find applications in many fields of biomedical research, as well as in clinical applications. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 2334-2536
  eISSN:
• Record 39 of
  
  Title:Advanced lead-free double perovskites/silica hybrid nanocrystals for highly stable light-emitting diodes
  
  Author(s):Shi, Jindou; Wang, Zeyu; Xu, Luxia; Wang, Junnan; Da, Zheyuan; Zhang, Chen; Ji, Yongqiang; Yao, Qing; Xu, Youlong; Gaponenko, Nikolai V.; Tian, Jinshou; Wang, Minqiang
  Source: JOURNAL OF MATERIALS CHEMISTRY C  Volume:   Issue:   DOI: 10.1039/d4tc00585f  Published: 2024  
  Abstract:The commercial viability of fluorescent materials is critically contingent on their thermal stability. Recent interest has converged on lead-free double perovskites (DPs), renowned for their optical properties mirroring those of traditional lead-based counterparts and superior atmospheric stability. However, these materials encounter significant fluorescence degradation in thermal environments, a challenging scenario given the high temperatures endemic to the surfaces of optoelectronic devices during prolonged operation, detrimentally impacting the fluorescent attributes of lead-free DPs. To address this challenge, in situ synthesis of lead-free DP nanocrystals (NCs) within KIT-6 mesoporous molecular sieves is proposed, yielding Cs2AgIn0.98Bi0.02Cl6@KIT-6 NCs with enhanced optical qualities. Experimental results demonstrate a marked enhancement in the fluorescence thermal stability of these NCs, attributed to the protective KIT-6 shell layer. Subjected to high power operation (100 mA) for 270 minutes, the fabricated orange light-emitting diode (LED) device maintained 80% of initial luminous efficiency, despite the resultant elevated surface temperature of 326.8 K. Therefore, this novel in situ assembly approach significantly bolsters the operational stability of lead-free DPs, paving the way for their potential commercial applications. Cs2AgIn0.98Bi0.02Cl6@KIT-6 NCs were obtained by in situ assembly within KIT-6 mesoporous molecular sieves, and their fluorescence thermal stability was significantly improved benefiting from the protection of the KIT-6 shell layer.
  Accession Number:
  ISSN: 2050-7526
  eISSN: 2050-7534
• Record 40 of
  
  Title:Linear-space-variant model for Fourier ptychographic microscopy
  
  Author(s):Feng, Tianci; Wang, Aiye; Wang, Zhiping; Liao, Yizheng; Pan, An
  Source: OPTICS LETTERS  Volume: 49  Issue: 10  DOI: 10.1364/OL.522745  Published: 2024  
  Abstract:Fourier ptychographic microscopy (FPM) needs to realize well-accepted reconstruction by image segmentation and discarding problematic data due to artifacts caused by vignetting. However, the imaging results have long suffered from uneven color blocks and the consequent digital stitching artifacts, failing to bring satisfying experiences to researchers and users over the past decade since the invention of FPM. In fact, the fundamental reason for vignetting artifacts lies in that the acquired data does not match the adopted linear-space-invariant (LSI) forward model, i.e., the actual object function is modulated by a quadratic phase factor during data acquisition, which has been neglected in the advancement of FPM. In this Letter, we rederive a linear-space-variant (LSV) model for FPM and design the corresponding loss function for FPM, termed LSV-FPM. Utilizing LSV-FPM for optimization enables the efficient removal of wrinkle artifacts caused by vignetting in the reconstruction results, without the need of segmenting or discarding images. The effectiveness of LSV-FPM is validated through data acquired in both 4f and finite conjugate
  Accession Number:
  ISSN: 0146-9592
  eISSN: 1539-4794
• Record 41 of
  
  Title:Forming quality optimization of 2219 aluminum alloy thin-walled complex components based on fracture constraint in spin forming
  
  Author(s):Li, Rui; Zheng, Zebang; Zhao, Tao; Liu, Qi; Yu, Zhenyang; Zhang, Hongrui
  Source: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY  Volume:   Issue:   DOI: 10.1007/s00170-024-13759-6  Published: 2024  
  Abstract:The 2219 aluminum alloy thin-walled complex components manufactured by spin forming are frequently applied to the bottom end of rocket fuel tanks. However, fracture and quality problems (large part-mold contact gap, low roundness, thickness accuracy) are prone to occur during their multi-pass spin forming. While the material anisotropy, complicated components geometry and the complex stress state evolution make it difficult to obtain the appropriate forming process parameters in spin forming. With the help of finite element methods, it is possible to solve this difficulty. Thus, based on the anisotropic Barlat89 yield function and the DF2016 fracture criterion, a spin forming finite element model considering material anisotropy and damage evolution is established first for the components. Then, a method by using multi-pass involute spinning track with variable diameter base circle to form the components is proposed, and also the spinning passes are determined. Finally, taking the non-fracture as the constraint condition and the forming quality indexes (part-mold contact gap, roundness, and thickness accuracy) as the optimization objectives, a multi-objective optimization model based on orthogonal experimental design and response surface model is established. The optimized process parameters are solved and determined by a combination of the Archive-Based Micro Genetic Algorithm, and the optimized results are verified by the experiments.
  Accession Number:
  ISSN: 0268-3768
  eISSN: 1433-3015
• Record 42 of
  
  Title:Synergistic effects and competitive relationships between DOC and DOX as acting on DNA molecules: Studied with confocal Raman spectroscopy and molecular docking technology
  
  Author(s):Zhou, Suli; Feng, Xiaoqiang; Bai, Jintao; Sun, Dan; Yao, Baoli; Wang, Kaige
  Source: HELIYON  Volume: 10  Issue: 9  DOI: 10.1016/j.heliyon.2024.e30233  Published: 2024  
  Abstract:Docetaxel (DOC) is one of the second-generation antineoplastic drugs of the taxanes family with excellent antitumor activity. However, the mechanism of DOC inducing tumor cell apoptosis and treating cancer diseases, especially its interaction with DNA in the nucleus, and its adjuvant or combined Doxorubicin (DOX) acting on DNA molecules are unclear. In this study, the interaction mechanism between DOC and DNA, as well as the synergistic effects and competitive relationships among DOC and DOX when they simultaneously interact with DNA molecules were studied by laser confocal Raman spectroscopy combined with UV-visible absorption spectroscopy and molecular docking technology. The spectroscopic results showed that the binding constant of DOC to DNA is 5.25 x 103 M-1, the binding modes of DOC and DNA are non-classical intercalation and electrostatic binding, and the DNA-DOC complex has good stability. When DOC or DOX interacts with DNA alone, both of them can bind with bases and phosphate backbone of DNA, and also lead to DNA conformation changes; when DOC and DOX interact with DNA at the same time, the orders of interaction not only affect their binding sites with DNA, but also cause changes in the surrounding environment of the binding sites. In addition, the molecular docking results further verified that DOC and DOX have synergy and competition when they interact with DNA molecules simultaneously. The docking energies of DNA-DOC and DNA-DOX indicate the important role of van der Waals forces and hydrogen bonds. This study has practical significance for the design and development of antitumor drugs with less toxic based on the taxanes family and the combination with other drugs for the treatment of cancer.
  Accession Number: e30233
  ISSN:
  eISSN: 2405-8440
• Record 43 of
  
  Title:Single shot depth-resolved imaging through dynamic turbid media
  
  Author(s):Li, Runze; Peng, Tong; Bai, Chen; Zhou, Meiling; Yu, Xianghua; Min, Junwei; Yang, Yanlong; Yao, Baoli
  Source: APPLIED PHYSICS LETTERS  Volume: 124  Issue: 20  DOI: 10.1063/5.0201501  Published: 2024  
  Abstract:Guide star assisted wavefront shaping techniques have been exploited for focusing and imaging through turbid media by addressing a scatter inverse pattern. However, the turbid medium is required to be steady before finding the proper correction pattern, which limits applications in focusing and imaging through dynamic media, such as turbid water or blood. This study proposes a holography-based dual-polarization computational wavefront shaping method for imaging objects at variant depths behind dynamic turbid media. The orthogonal polarized output speckles of a point source (considered as a guide star) and an object are simultaneously recorded in holograms in separate regions of a single CCD camera. The holograms of the point source and object are subjected to the same distortion regardless of whether the media is static or dynamic. The hologram of the point source is used to determine the correction phase pattern for the distortion, while that of the object is used to record the complex scattered wavefront of the object. To reconstruct a clear object image, the wavefront of the scattered object is digitally corrected using the correction phase pattern and is then transferred to the image plane by calculating the transmission of the angular spectrum. Benefiting from the autofocusing feature of digital holography, objects at different depths can be recovered from a single shot hologram pair. The potential applications of the proposed method in diverse dynamic scattering media are demonstrated by imaging through a moving diffuser, turbid water, and pig blood with optical depth beyond 10.
  Accession Number: 201109
  ISSN: 0003-6951
  eISSN: 1077-3118
• Record 44 of
  
  Title:Efficient characterizations of multiphoton states with an ultra-thin optical device
  
  Author(s):An, Kui; Liu, Zilei; Zhang, Ting; Li, Siqi; Zhou, You; Yuan, Xiao; Wang, Leiran; Zhang, Wenfu; Wang, Guoxi; Lu, He
  Source: NATURE COMMUNICATIONS  Volume: 15  Issue: 1  DOI: 10.1038/s41467-024-48213-4  Published: 2024  
  Abstract:Metasurface enables the generation and manipulation of multiphoton entanglement with flat optics, providing a more efficient platform for large-scale photonic quantum information processing. Here, we show that a single metasurface optical device would allow more efficient characterizations of multiphoton entangled states, such as shadow tomography, which generally requires fast and complicated control of optical setups to perform information-complete measurements, a demanding task using conventional optics. The compact and stable device here allows implementations of general positive operator valued measures with a reduced sample complexity and significantly alleviates the experimental complexity to implement shadow tomography. Integrating self-learning and calibration algorithms, we observe notable advantages in the reconstruction of multiphoton entanglement, including using fewer measurements, having higher accuracy, and being robust against experimental imperfections. Our work unveils the feasibility of metasurface as a favorable integrated optical device for efficient characterization of multiphoton entanglement, and sheds light on scalable photonic quantum technologies with ultra-thin optical devices. Shadow tomography is efficient for quantum state characterization. Here, the authors implement shadow tomography on photonic states with a single metasurface, which alleviates the complexity in measurement
  Accession Number: 3944
  ISSN:
  eISSN: 2041-1723
• Record 45 of
  
  Title:Simulation of evaporation ablation dynamics of materials by nanosecond pulse laser of Gaussian beam and flat-top beam
  
  Author(s):Yin Pei-Qi; Xu Bo-Ping; Liu Ying-Hua; Wang Yi-Shan; Zhao Wei; Tang Jie
  Source: ACTA PHYSICA SINICA  Volume: 73  Issue: 9  DOI: 10.7498/aps.73.20231625  Published: 2024  
  Abstract:Based on the established two-dimensional asymmetric model of the interaction between a nanosecond pulse laser and metallic aluminum, the effect of beam shaping on the evaporation ablation dynamics during the ablation of metallic aluminum by a nanosecond pulse laser is simulated. The results show that plasma shielding, which has a significant influence on the ablation properties of the target, occurs mainly in the middle phase and late phase of the pulse. Among the three laser profiles, the Gaussian beam has the strongest shielding effect. As the diameter of the reshaped flat-top beam increases, the shielding effect gradually weakens. The two-dimensional spatial distribution of target temperature is relatively different between ablation by a Gaussian beam and that by a flat-top beam. For the Gaussian beam, the center of the target is first heated, and then the temperature spreads in radial direction and axial direction. For the flat-top beam, due to the uniform energy distribution, the target is heated within a certain radial range simultaneously. Beam shaping has a great influence on the evaporation ablation dynamics of the target. For the Gaussian beam, the center of the target is first ablated, followed by the radial ablation. For the flat-top beam, the evaporation time of the target surface is delayed due to the lower energy density after the beam has been shaped. In addition, the target evaporates simultaneously in a certain radial range due to the more uniform distribution of laser energy. For each of the three laser profiles, the evaporation morphology of the target resembles the intensity distribution of the laser beam. The crater produced by the Gaussian beam is deep in the center and shallow on both sides, while it becomes relatively flat by the flat-top beam.
  Accession Number: 95202
  ISSN: 1000-3290
  eISSN:
• Record 46 of
  
  Title:A Dual-FSM GI LiDAR Imaging Control Method Based on Two-Dimensional Flexible Turntable Composite Axis Tracking
  
  Author(s):Cao, Yu; Xie, Meilin; Wang, Haitao; Hao, Wei; Guo, Min; Jiang, Kai; Wang, Lei; Guo, Shan; Wang, Fan
  Source: REMOTE SENSING  Volume: 16  Issue: 10  DOI: 10.3390/rs16101679  Published: 2024  
  Abstract:In this study, a tracking and pointing control system with a dual-FSM (fast steering mirror) two-dimensional flexible turntable composite axis is proposed. It is applied to the target-tracking accuracy control in a GI LiDAR (ghost imaging LiDAR) system. Ghost imaging is a multi-measurement imaging method; the dual-FSM GI LiDAR tracking and pointing imaging control system proposed in this study mainly solves the problems of the high-resolution remote sensing imaging of high-speed moving targets and various nonlinear disturbances when this technology is transformed into practical applications. Addressing the detrimental effects of nonlinear disturbances originating from internal flexible mechanisms and assorted external environmental factors on motion control's velocity, stability, and tracking accuracy, a nonlinear active disturbance rejection control (NLADRC) method based on artificial neural networks is advanced. Additionally, to overcome the limitations imposed by receiving aperture constraints in GI LiDAR systems, a novel optical path design for the dual-FSM GI LiDAR tracking and imaging system is put forth. The implementation of the described methodologies culminated in the development of a dual-FSM GI LiDAR tracking and imaging system, which, upon thorough experimental validation, demonstrated significant improvements. Notably, it achieved an improvement in the coarse tracking accuracy from 193.29 mu rad (3 sigma) to 87.21 mu rad (3 sigma) and enhanced the tracking accuracy from 10.1 mu rad (sigma) to 1.5 mu rad (sigma) under specified operational parameters. Furthermore, the method notably diminished the overshoot during the target capture process from 28.85% to 12.8%, concurrently facilitating clear recognition of the target contour. This research contributes significantly to the advancement of GI LiDAR technology for practical application, showcasing the potential of the proposed control and design strategies in enhancing system performance in the face of complex disturbances.
  Accession Number: 1679
  ISSN:
  eISSN: 2072-4292
• Record 47 of
  
  Title:High Fidelity Full-Color Optical Sectioning Structured Illumination Microscopy by Fourier Domain Based Reconstruction
  
  Author(s):Dang, Shipei; Qian, Jia; Ma, Wang; Ma, Rui; Li, Xing; Wang, Siying; Bai, Chen; Dan, Dan; Yao, Baoli
  Source: PHOTONICS  Volume: 11  Issue: 5  DOI: 10.3390/photonics11050405  Published: 2024  
  Abstract:The natural color of biological specimens plays a crucial role in body protection, signaling, physiological adaptations, etc. Full-color optical sectioning structured illumination microscopy (OS-SIM) color is a promising approach that can reconstruct biological specimens in three-dimension meanwhile maintaining their natural color. Full-color OS-SIM takes the advantages of rapid imaging speed, compatibility with fluorescence and non-fluorescence samples, compact configuration, and low cost. However, the commonly used HSV-RMS reconstruction algorithm for full-color OS-SIM faces two issues to be improved. One is the RMS (root-mean-square) OS reconstruction algorithm is prone to background noise, and the other is the reconstruction is bound in RGB and HSV color spaces, consuming more reconstructing time. In this paper, we propose a full-color Fourier-OS-SIM method that allows for the OS reconstruction using the high-frequency spectrum of the sample and thus is immune to the low-frequency background noise. The full-color Fourier-OS-SIM directly runs in the RGB color space, providing an easy way to restore the color information. Simulation and experiments with various samples (pollen grains and tiny animals) demonstrate that the full-color Fourier-OS-SIM method is superior to the HSV-RMS method regarding background noise suppression. Moreover, benefiting from the background noise suppression merit, the quantitative morphological height map analysis with the full-color Fourier-OS-SIM method is more accurate. The proposed full-color Fourier-OS-SIM method is expected to find broad applications in biological and industrial fields where the 3D morphology and the color information of objects both need to be recovered.
  Accession Number: 405
  ISSN:
  eISSN: 2304-6732
• Record 48 of
  
  Title:A frequency-response-optimized Shack-Hartmann zonal wavefront reconstructor based on Fan's model
  
  Author(s):Fan, Yao; Duan, Yaxuan; Da, Zhengshang; Yue, Yang
  Source: REVIEW OF SCIENTIFIC INSTRUMENTS  Volume: 95  Issue: 5  DOI: 10.1063/5.0197071  Published: 2024  
  Abstract:This paper introduces an optimized method for zonal wavefront reconstruction utilizing Fan's model, specifically tailored to enhance the frequency response. Analysis of the system frequency response demonstrates a 27% increase in bandwidth compared to the Southwell model. Examination of reconstruction errors at various frequency points reveals consistently smaller values when compared to the Southwell model. Validation through numerical simulations and real experiments underscores the superior performance of the proposed reconstructor, particularly noticeable at higher response levels within the mid- and high-frequency domains.
  Accession Number: 55004
  ISSN: 0034-6748
  eISSN: 1089-7623