2024

• Record 49 of
  
  Title:Spectral imaging based on custom-made multi-strip filter arrays
  
  Author(s):Guo, Quan; Wu, Dengshan; Yu, Weixing
  Source: APPLIED OPTICS  Volume: 63  Issue: 13  DOI: 10.1364/AO.522642  Published: 2024  
  Abstract:Spectral imaging technology based on on -chip spectroscopy can find applications in areas including aerospace, industrial and consumer electronics, and so on. Since each application normally requires a different set and number of spectral bands, the development of customized spectroscopy solutions with more compact size and lower cost becomes quite important. In this paper, we demonstrate a compact, highly customizable imaging spectrometer scheme based on custom-made multi -strip filter arrays, which maintains an average high transmission of similar to 85%, narrow bandwidth of similar to 30 nm, and high optical density of similar to OD2 in the blocking regions across the visible to nearinfrared waveband. Spectral imaging experiments are conducted, and the accurate reconstruction of sparse spectral image data is demonstrated as well to prove the validity of the proposed scheme. As a result, the work reported in this paper allows researchers to develop customized spectral imaging equipment in a relatively easy way and also has a great potential to be engineered further for scalable production with a quite low cost. (c) 2024 Optica Publishing Group
  Accession Number:
  ISSN: 1559-128X
  eISSN: 2155-3165
• Record 50 of
  
  Title:Study on Spectrum Shifting and Pulse Splitting of Mode-Locked Fiber Lasers Based on NPR Technology
  
  Author(s):Hao, Zhenhua; Hu, Yu; Zhou, Siyu; Liu, Jinhui; Li, Xiaohui; Wang, Yishan; Gao, Cunxiao
  Source: NANOMATERIALS  Volume: 14  Issue: 9  DOI: 10.3390/nano14090739  Published: 2024  
  Abstract:We conducted a systematic investigation into the spectral and pulse characteristics of C and L-band Nonlinear Polarization Rotation (NPR) mode-locked fiber lasers effectively employing nonlinear polarization rotation technology. In our experimental setup, we achieved a stable mode-locked state at 1560.076 nm, exhibiting a 3 dB spectral bandwidth of 9.1 nm. As the pump power increased, we observed spectral shifts accompanied by shifts in the first Kelly sideband and the generation of new Kelly sidebands. In this paper, the phenomenon of spectral deviation is elucidated through the interplay of self-phase modulation, group velocity drift, and polarization-dependent isolator (PD-ISO) filter effect, with an analysis of the formation and deviation of Kelly sidebands. Notably, spectral shift persisted even when the pump power exceeded 200 mW. However, continuous pump power escalation led to soliton splitting, resulting in the formation of new soliton beams. Based on the simultaneous generation of spectral shift and pulse splitting, our study contributes to an enhanced understanding of soliton dynamics in ultrafast fiber lasers and lays a foundation for the application of high-repetition-frequency harmonic mode-locked lasers with tunable wavelengths.
  Accession Number: 739
  ISSN:
  eISSN: 2079-4991
• Record 51 of
  
  Title:Integrating a Physical Model with Multi-Objective Optimization for the Design of Optical Angle Nano-Positioning Mechanism
  
  Author(s):Jiang, Bo; Dong, Yiming; Zhang, Zijie; Li, Xiangyu; Wei, Yuxuan; Guo, Yifan; Liu, Haixia
  Source: APPLIED SCIENCES-BASEL  Volume: 14  Issue: 9  DOI: 10.3390/app14093756  Published: 2024  
  Abstract:In light of recent advancements in synchrotron radiation technology and nano-technology, there has been a marked increase in the need for ultra-precision nano-positioning mechanisms. This paper presents a method that integrates physical models with multi-objective optimization for developing an optical angle nano-positioning mechanism. We begin by examining the actual motion law of the mechanism, based on kinematic principles. The outcomes from this kinematic analysis facilitate a static analysis of the flexible hinge, identified as a critical component of the mechanism. Subsequently, we establish a dynamic model for the entire mechanism. By employing the physical model as a base and combining it with the optimization algorithm, we identify the optimal design parameters for the mechanism. The design achieves a resolution of 50 nrad and meets the specified requirements. The first-order inherent frequency of the mechanism is approximately 43.75 Hz. There is a discrepancy of 2.63% from the finite element modal analysis results and a 3.33% difference from the theoretical analysis results, validating the reliability of the design method proposed in this study.
  Accession Number: 3756
  ISSN:
  eISSN: 2076-3417
• Record 52 of
  
  Title:Laser-guided anisotropic etching for precision machining of micro-engineered glass components
  
  Author(s):Li, Jun; Zhong, Shuai; Huang, Jiaxu; Qiu, Pei; Wang, Pu; Li, Hui; Qin, Chu; Miao, Duo; Xu, Shaolin

  Source: INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE  Volume: 198 DOI: 10.1016/j.ijmachtools.2024.104152  Published: 2024  

  Abstract:Micro-engineered glass components play a vital role in various domains, but their full potential remains untapped due to the lack of easily accessible high-precision machining methods for customizable microstructure. Our discovery of a new phenomenon, where laser-modified regions break the rule of inherently isotropic glass etching and regulate a directional anisotropic etching along modified tracks, has led to the development of a laser-guided anisotropic etching (LGAE) method. This method enables crafting precision glass microstructures with sharp features, smooth surfaces, and adjustable shapes and sizes. An ultrafast Bessel beam is utilized to create high aspect-ratio line-shaped modification within the glass. With a higher etching rate than pristine glass, the modified line guides directional anisotropic etching along the modified track, facilitating the formation of a V-shape with an angle altered by the etching ratio. These modified lines can further serve as basic building blocks to interconnect to construct a 3D internal modification region and then guide the glass's overall surface morphology etching evolution, enabling the creation of microstructures featuring designable shapes and adjustable feature sizes. To accurately predict and control the shape of the microstructures, we establish a finite difference etching model that incorporates localized etching rate regulation, validating the robustness and controllability of LGAE. This scalable method has successfully fabricated a 50 mu m period micro-pyramid array with high uniformity over a centimeter-scale area, demonstrating its suitability for large-scale manufacturing. The showcased micro-engineered glass components encompass V-groove arrays for fiber alignment, blazed gratings for light modulation, and microchannels with customized trajectories for microfluidic chips. These advancements driven by LGAE can significantly contribute to the progress of glass-based research and industries.

  Accession Number: 104152

  ISSN: 0890-6955

  eISSN: 1879-2170
• Record 53 of
  
  Title:A systematic study on linear thermal expansion coefficient of metals based on interferometric measurement with Fresnel bimirror
  
  Author(s):Lu, Sifan; Zhao, Wenyu; Lin, Jia; Zhao, Xiaorui; Xu, Ruoyu; Bai, Jin; Sun, Chunyan
  Source: MICROWAVE AND OPTICAL TECHNOLOGY LETTERS  Volume: 66  Issue: 5  DOI: 10.1002/mop.34178  Published: 2024  
  Abstract:Linear thermal expansion coefficient, which is vital for measuring the thermal expansion characteristics of metals, has been attracting considerable attention globally. Herein, a novel design based on Fresnel bimirror has been developed. In this design, when the upper end of the object to be measured comes in contact with a tilted double-sided mirror, the temperature rises and intersection angle of the Fresnel bimirror decreases. Meanwhile, interference fringe spacing becomes narrower, while the number of fringes increases. An imaging system based on a digital microscope and smartphone is also incorporated in this design, which records the changes in the interference fringes. Then, using a self-programmed software, the linear thermal expansion coefficients of Cu, Fe, and Al samples are determined at elevated temperatures as 17.85 +/- 0.23 x 10-6/degrees C (alpha Cu _{C{\rm{u}}}$), 11.8 +/- 0.09 x 10-6/degrees C (alpha Fe _{F{\rm{e}}}$), and 23.34 +/- 0.16 x 10-6/degrees C (alpha Al _{Al}$), respectively, with a relative error of less than 1.6%. A cooling process is also designed, and the average value of the linear thermal expansion coefficient of metal samples during heating and cooling conditions is determined. The measurement results obtained via the finite-method simulation demonstrate the feasibility and reliability of the system. Overall, this study provides a new idea for measuring the linear thermal expansion coefficient of metals.
  Accession Number: e34178
  ISSN: 0895-2477
  eISSN: 1098-2760
• Record 54 of
  
  Title:Switchable hybrid-order optical vortex lattice
  
  Author(s):Qin, Xueyun; Zhang, Hao; Tang, Miaomiao; Zhou, Yujie; Tai, Yuping; Li, Xinzhong
  Source: OPTICS LETTERS  Volume: 49  Issue: 9  DOI: 10.1364/OL.515906  Published: 2024  
  Abstract:Optical vortex (OV) modulation is a powerful technique for enhancing the intrinsic degrees -of -freedom in structured light applications. Particularly, the lattices involving multiple OVs have garnered significant academic interest owing to their wide applicability in optical tweezers and condensed matter physics. However, all OVs in a lattice possess the same order, which cannot be modulated individually, limiting its versatile application. Herein, we propose, to our knowledge, a novel concept, called the hot -swap method, to design a switchable hybrid -order OV lattice, in which each OV is easily replaced by arbitrary orders. We experimentally generated the switchable hybrid -order OV lattice and studied its characteristics, including interferograms, retrieved phase, energy flow, and orbital angular momentum. Furthermore, the significant advantages of the switchable hybrid -order OV lattice are demonstrated through the independent manipulation of multiple yeast cells. This study provides a novel scheme for accurate control and modulation of OV lattices, which greatly facilitates the diverse applications of optical manipulation and particle trapping and control. (c) 2024 Optica Publishing Group
  Accession Number:
  ISSN: 0146-9592
  eISSN: 1539-4794
• Record 55 of
  
  Title:Exploration of Eye Fatigue Detection Features and Algorithm Based on Eye-Tracking Signal
  
  Author(s):Sun, Weifeng; Wang, Yuqi; Hu, Bingliang; Wang, Quan
  Source: ELECTRONICS  Volume: 13  Issue: 10  DOI: 10.3390/electronics13101798  Published: 2024  
  Abstract:Eye fatigue has a fatiguing effect on the eye muscles, and eye movement performance is a macroscopic response to the eye fatigue state. To detect and prevent the risk of eye fatigue in advance, this study designed an eye fatigue detection experiment, collected experimental data samples, and constructed experimental data sets. In this study, eye-tracking feature extraction was completed, and the significance difference of eye-tracking features under different fatigue states was discussed by two-way repeated-measures ANOVA (Analysis of Variance). The experimental results demonstrate the feasibility of eye fatigue detection from eye-tracking signals. In addition, this study considers the effects of different feature extraction methods on eye fatigue detection accuracy. This study examines the performance of machine learning algorithms based on manual feature calculation (SVM, DT, RM, ET) and deep learning algorithms based on automatic feature extraction (CNN, auto-encoder, transformer) in eye fatigue detection. Based on the combination of the methods, this study proposes the feature union auto-encoder algorithm, and the accuracy of the algorithm for eye fatigue detection on the experimental dataset is improved from 82.4% to 87.9%.
  Accession Number: 1798
  ISSN:
  eISSN: 2079-9292
• Record 56 of
  
  Title:Classification of Benign-Malignant Thyroid Nodules Based on Hyperspectral Technology
  
  Author(s):Wang, Junjie; Du, Jian; Tao, Chenglong; Qi, Meijie; Yan, Jiayue; Hu, Bingliang; Zhang, Zhoufeng
  Source: SENSORS  Volume: 24  Issue: 10  DOI: 10.3390/s24103197  Published: 2024  
  Abstract:In recent years, the incidence of thyroid cancer has rapidly increased. To address the issue of the inefficient diagnosis of thyroid cancer during surgery, we propose a rapid method for the diagnosis of benign and malignant thyroid nodules based on hyperspectral technology. Firstly, using our self-developed thyroid nodule hyperspectral acquisition system, data for a large number of diverse thyroid nodule samples were obtained, providing a foundation for subsequent diagnosis. Secondly, to better meet clinical practical needs, we address the current situation of medical hyperspectral image classification research being mainly focused on pixel-based region segmentation, by proposing a method for nodule classification as benign or malignant based on thyroid nodule hyperspectral data blocks. Using 3D CNN and VGG16 networks as a basis, we designed a neural network algorithm (V3Dnet) for classification based on three-dimensional hyperspectral data blocks. In the case of a dataset with a block size of 50 x 50 x 196, the classification accuracy for benign and malignant samples reaches 84.63%. We also investigated the impact of data block size on the classification performance and constructed a classification model that includes thyroid nodule sample acquisition, hyperspectral data preprocessing, and an algorithm for thyroid nodule classification as benign and malignant based on hyperspectral data blocks. The proposed model for thyroid nodule classification is expected to be applied in thyroid surgery, thereby improving surgical accuracy and providing strong support for scientific research in related fields.
  Accession Number: 3197
  ISSN:
  eISSN: 1424-8220
• Record 57 of
  
  Title:Design of an optical passive semi-athermalization zoom lens
  
  Author(s):Yan, Aqi; Chen, Weining; Li, Qianxi; Guo, Min; Wang, Hao
  Source: APPLIED OPTICS  Volume: 63  Issue: 13  DOI: 10.1364/AO.517025  Published: 2024  
  Abstract:Traditional zoom lenses cannot clearly image during the entire zoom process when the ambient temperature changes and needs to focus frequently at middle focal length positions. An innovative design method called the optical passive semi-athermalization (OPSA) design for zoom optical systems is proposed which, based on the difference in the focusing sensitivity of the focusing group at short and long focal length positions, seeks out sensitive groups that have a greater impact on the imaging quality at the short focal position. By changing the temperature characteristics of the temperature-sensitive lenses in these groups, an OPSA zoom optical system can be realized, which exhibits a compact structure and excellent imaging quality. Under the ambient temperature of - 40 degrees C to + 60 degrees C, the OPSA zoom lens needs to refocus only once at the long focal length position, which can ensure an image clearly during the entire zoom process. Remarkably, this innovative method not only mitigates the frequent focusing challenges in traditional zoom lenses, but also contributes to the diminutive size. (c) 2024 Optica Publishing Group
  Accession Number:
  ISSN: 1559-128X
  eISSN: 2155-3165
• Record 58 of
  
  Title:Hierarchical Semantic-Guided Contextual Structure-Aware Network for Spectral Satellite Image Dehazing
  
  Author(s):Yang, Lei; Cao, Jianzhong; Wang, Hua; Dong, Sen; Ning, Hailong
  Source: REMOTE SENSING  Volume: 16  Issue: 9  DOI: 10.3390/rs16091525  Published: 2024  
  Abstract:Haze or cloud always shrouds satellite images, obscuring valuable geographic information for military surveillance, natural calamity surveillance and mineral resource exploration. Satellite image dehazing (SID) provides the possibility for better applications of satellite images. Most of the existing dehazing methods are tailored for natural images and are not very effective for satellite images with non-homogeneous haze since the semantic structure information and inconsistent attenuation are not fully considered. To tackle this problem, this study proposes a hierarchical semantic-guided contextual structure-aware network (SCSNet) for spectral satellite image dehazing. Specifically, a hybrid CNN-Transformer architecture integrated with a hierarchical semantic guidance (HSG) module is presented to learn semantic structure information by synergetically complementing local representation from non-local features. Furthermore, a cross-layer fusion (CLF) module is specially designed to replace the traditional skip connection during the feature decoding stage so as to reinforce the attention to the spatial regions and feature channels with more serious attenuation. The results on the SateHaze1k, RS-Haze, and RSID datasets demonstrated that the proposed SCSNet can achieve effective dehazing and outperforms existing state-of-the-art methods.
  Accession Number: 1525
  ISSN:
  eISSN: 2072-4292
• Record 59 of
  
  Title:Adaptive decision threshold algorithm based on a sliding window to reduce BER of free-space optical communication systems
  
  Author(s):Ying, Ruilei; Zheng, Yunqiang; Wei, Sentao; He, Yuanchen; Xie, Zhuang; He, Mingze; Wang, Wei
  Source: APPLIED OPTICS  Volume: 63  Issue: 13  DOI: 10.1364/AO.519321  Published: 2024  
  Abstract:Free-space optical communication (FSOC) systems face susceptibility to several factors, such as transmission distance, atmospheric turbulence, and alignment errors. These elements contribute to fluctuations in the signal strength reaching the receiver. The resultant signal fluctuations can result in misjudgments and an elevated bit error rate (BER). This paper proposes an adaptive decision threshold algorithm based on a sliding window (ADTSW). By estimating received signal parameters and delimiting the amplitude interval, the algorithm ensures that the decision threshold tracks signal fluctuations, thereby reducing signal misjudgment. The effectiveness of the algorithm is validated through simulations and experimentation. When the signal peak-to-peak value fluctuates, simulation results demonstrate that the proposed algorithm achieves a 1-order-of-magnitude reduction in BER compared to the traditional fixed decision threshold (FDT) method. Under the influence of weak atmospheric turbulence with different scintillation variance, both simulation and experimentation indicate a 1-order-of-magnitude reduction in BER compared to the FDT method. The ADTSW algorithm proves its capability in minimizing misjudgments, thereby effectively reducing BER and improving communication quality. (c) 2024 Optica Publishing Group
  Accession Number:
  ISSN: 1559-128X
  eISSN: 2155-3165
• Record 60 of
  
  Title:An Infrared Evanescent Wave Sensor for Detection of Ascorbic Acid in Food and Drugs
  
  Author(s):You, Tianxiang; Zhao, Yongkun; Xu, Yantao; Guo, Haitao; Zhu, Jihong; Tao, Haizheng; Zhang, Xianghua; Xu, Yinsheng
  Source: JOURNAL OF LIGHTWAVE TECHNOLOGY  Volume: 42  Issue: 9  DOI: 10.1109/JLT.2024.3357491  Published: 2024  
  Abstract:An infrared evanescent wave sensor was developed to accurately detect ascorbic acid (vitamin C) in food and drugs. The sensor was fabricated by tapering and bending of As2S3 infrared fibers. Due to the broad transmission range (5000-1500 cm(-1)) of the infrared fibers, covering the characteristic absorption peak of ascorbic acid (C = O at 1760 cm(-1) and C = C at 1690 cm(-1)), the sensor is capable of accurately identifying and detecting the concentration of ascorbic acid. Experimental results demonstrated that a conically tapered fiber sensor with a waist diameter of 50 mu m, waist length of 30 mm, and a radius of 2 mm achieved a maximum sensitivity of 0.1257 (a.u./(mg center dot ml(-1))) and a limit of detection (LoD) of 0.917 mg/ml. Furthermore, the application of this fiber sensor in various vitamin C-containing tablets and juices validated its high accuracy and minimal measurement deviation (as low as 0.19 mg/ml). Compared to traditional detection methods, the sensor not only provides a faster and cost-effective solution to identify the substance but also maintains high accuracy. It offers a new approach to quantitative and qualitative analysis of food and drugs.
  Accession Number:
  ISSN: 0733-8724
  eISSN: 1558-2213