Optics and Lasers in Engineering最新文献

{"title":"Trace gas detection using anti-resonant hollow-core fiber Raman spectroscopy based on a multi-stage spatial filtering method","authors":"Yukun Wan,&nbsp;Xudong Li,&nbsp;Zhehan Wang,&nbsp;Xinyang Liu,&nbsp;Min Xia,&nbsp;Li Xia,&nbsp;Wei Li","doi":"10.1016/j.optlaseng.2025.109341","DOIUrl":"10.1016/j.optlaseng.2025.109341","url":null,"abstract":"<div><div>Hollow-core anti-resonant fibers (HC-ARFs) have demonstrated remarkable advantages in gas-phase Raman spectroscopy in recent years. However, the background fluorescence surrounding the Raman signal within the fiber core typically exhibits a ring-like but spatially non-uniform distribution, which often overwhelms weak Raman features of trace gases, thus limiting the detection sensitivity. To address this issue, we propose a Raman spectroscopic gas detection system based on hollow-core anti-resonant fiber (HC-ARF), incorporating a multi-stage spatial filtering strategy tailored to the spatially non-uniform distribution of Raman signals and background noise. To implement this strategy, a custom imaging spectrometer was developed, integrating three cascaded spatial filtering components: radial filtering using an iris diaphragm, longitudinal filtering via a precision slit, and lateral filtering through CCD row-selective integration. Compared to the unfiltered condition, this method suppresses approximately 94% of the spectral background noise and enhances the signal-to-noise ratio (SNR) by a factor of 9.4. The system achieves high-sensitivity detection of ¹³CO₂ and ¹²CO₂ in ambient air, with detection limits reaching 0.07 ppm and 0.64 ppm, respectively. Notably, this system enables accurate identification of trace components without requiring complex gas pretreatment, even under high background gas interference. The proposed method provides a promising solution for field-deployable Raman-based gas sensing using HC-ARFs.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109341"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terahertz flat-top beam generation via triple-polarization-channel multiplexed metasurface","authors":"Jieyang Tang ,&nbsp;Jierong Cheng ,&nbsp;Shengjiang Chang","doi":"10.1016/j.optlaseng.2025.109357","DOIUrl":"10.1016/j.optlaseng.2025.109357","url":null,"abstract":"<div><div>Different from laser sources, terahertz emitters typically generate beams with spatial inhomogeneity and small aperture size due to limited power. This can limit system performance in applications such as imaging. Optical components for beam shaping are highly desirable. Leveraging metasurfaces' versatile wavefront manipulation capabilities and a non-orthogonal polarization multiplexing strategy, we demonstrate the simultaneous generation of terahertz flat-top beams in three distinct polarization channels. Specifically, circular, rectangular, and square beam profiles are achieved in the <em>x</em>-polarized, 45°, and <em>y</em>-polarized channels, respectively. By implementing the Gerchberg-Saxton angular spectrum iterative algorithm and constructing a full-parameter Jones matrix model, the generated flat-top beams with negligible crosstalk exhibit remarkable improvements in both intensity uniformity and edge steepness compared to the original terahertz source. These advancements enable precise radiation pattern engineering, addressing critical requirements across diverse terahertz applications.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109357"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Groundbreaking experimental demonstration of generalized chaos synchronization prediction in multi-drive unidirectionally-coupled laser systems using DFB-based photonic reservoir computing","authors":"Dongzhou Zhong,&nbsp;Hongen Zeng,&nbsp;Jiangtao Xi,&nbsp;Youmeng Wang,&nbsp;Zhanfeng Ren,&nbsp;Chenghao Qiu,&nbsp;Guihong Chen,&nbsp;Liuyang Guo,&nbsp;Kun Liu,&nbsp;Yang Xie,&nbsp;Wenxian Wu","doi":"10.1016/j.optlaseng.2025.109328","DOIUrl":"10.1016/j.optlaseng.2025.109328","url":null,"abstract":"<div><div>Photonic Reservoir Computing (PRC) has emerged as a powerful tool for complex photonic dynamics, offering distinct advantages over traditional methods that often struggle with causality modeling in unidirectionally coupled systems. In this study, we experimentally explore a PRC physical hardware system based on a delay-feedback distributed feedback (DFB) laser, uncovering its remarkable ability to learn unidirectional coupling schemes and predict the response dynamics of multi-drive systems using limited time-series data from the drive-response DFB laser system. After training with partial dynamics data from the drive-response semiconductor laser system, the PRC demonstrates precise prediction capability for the dynamics of the response DFB laser system across various drive optical signals sharing the same coupling scheme. Notably, even when the drive laser system is replaced, the PRC effectively reproduces the dynamics of the response laser system by leveraging the dynamics of the new drive system. Furthermore, the trained reservoir achieves high-quality synchronization with outputs from different drive-response systems. Our analysis delves into the effects of sampling period (<em>T</em> <!-->=<!--> <!-->30<!--> <!-->-<!--> <!-->60<!--> <!-->ns) and the number of virtual nodes (<em>N</em> <!-->=<!--> <!-->50<!--> <!-->-<!--> <!-->300) on the normalized mean square error (<em>NMSE</em>), while also confirming the robustness of feedback strength (<span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> <!-->=<!--> <!-->0.1<!--> <!-->-<!--> <!-->0.2) and injection strength (<span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>i</mi><mi>n</mi><mi>j</mi></mrow></msub></math></span> <!-->=<!--> <!-->0.06<!--> <!-->-<!--> <!-->0.2) to synchronization quality. Experimental results reveal that the PRC system consistently achieves high-quality chaotic synchronization (correlation coefficient <em>ρ</em> <!-->&gt;<!--> <!-->0.93) across various drive modes, with a prediction error <em>NMSE</em> less than 0.133. Particularly, when <em>T</em> <!-->=<!--> <!-->60<!--> <!-->ns and <em>N</em> <!-->=<!--> <!-->300, the <em>NMSE</em> of the drive-response system, constructed using optical feedback DFB lasers and optical injection DFB lasers, drops to as low as 0.0951, underscoring the efficacy of parameter optimization. This research highlights the generalization capability of PRC under complex drive signals, paving the way for a new paradigm in dynamics prediction for multi-physical field coupled systems. The findings hold significant promise for advancing applications in photonic computing and beyond.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109328"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SVC-FRET: Spatial-vector-based calibration on a FRET microscope","authors":"Yan Mao ,&nbsp;Yongqiang Liu ,&nbsp;Tian Pang ,&nbsp;Yue Wang ,&nbsp;Beini Sun ,&nbsp;Zhengfei Zhuang ,&nbsp;Min Hu ,&nbsp;Tongsheng Chen","doi":"10.1016/j.optlaseng.2025.109323","DOIUrl":"10.1016/j.optlaseng.2025.109323","url":null,"abstract":"<div><div>Accurate quantitative measurement of Förster resonance energy transfer (FRET) in living cells relies critically on precise system calibration parameters. Coullomb et al. introduced QuanTI-FRET, a method for determining system calibration parameters (<em>G</em> and <em>k</em>) through three-dimensional fitting using standard FRET plasmids of known stoichiometry. However, this method requires pre-determined spectral crosstalk coefficients (<em>a</em> and <em>d</em>) from donor-only and acceptor-only samples. To address this limitation, we propose SVC-FRET (spatial-vector-based calibration on a FRET microscope), which utilizes three-channel intensity distributions from three standard FRET plasmids to construct spatial vectors. Through fitting of these vectors under physical constraints, SVC-FRET simultaneously resolves five key parameters—including spectral crosstalk correction parameters (<span><math><mi>β</mi><mo>≈</mo><mi>a</mi></math></span>, <span><math><mi>δ</mi><mo>≈</mo><mi>d</mi></math></span>), system calibration parameters (<em>G</em>, <em>k</em>), and the acceptor-to-donor extinction coefficient ratio (<span><math><msub><mrow><mi>ε</mi></mrow><mrow><mi>A</mi></mrow></msub><mo>/</mo><msub><mrow><mi>ε</mi></mrow><mrow><mi>D</mi></mrow></msub></math></span>). Experimental results demonstrate that SVC-FRET-derived parameters enable reliable quantitative FRET analysis. Compared to QuanTI-FRET, SVC-FRET streamlines experimental workflows by eliminating the need for separate donor/acceptor samples and reduces potential errors from experimental condition inconsistencies, thereby enhancing robustness and measurement reliability.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109323"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beam distortion and pointing instability in non-critical phase matching second harmonic generation","authors":"Yingtong Shi ,&nbsp;Jiaqi Wang ,&nbsp;Xiang Zhang ,&nbsp;Zhongqi Liu ,&nbsp;Hang Xu ,&nbsp;Senlin Huang","doi":"10.1016/j.optlaseng.2025.109344","DOIUrl":"10.1016/j.optlaseng.2025.109344","url":null,"abstract":"<div><div>We propose a three-dimensional phase mismatch model for non-critical phase matching in second harmonic generation (NCPM-SHG). The model refines the simulation of NCPM-SHG and provides accurate predictions of beam distortion phenomena in NCPM-SHG. With the incorporation of temperature effects on phase matching, we derive the relationship between pointing jitter and temperature control precision of NCPM-SHG crystals. Our study with Lithium Triborate (LBO) crystals indicates that achieving pointing jitter below 20 μrad requires crystal temperature control precision to be better than 0.05 °C. Numerical simulations of the theoretical model were validated experimentally, in which the beam distortion and pointing jitter introduced by NCPM-SHG are analyzed quantitatively for the first time. Our research provides a valuable reference for optimizing beam profile and stability in laser systems based on NCPM-SHG.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109344"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anti-aliasing heterogeneous chirp modulation in FMCW LiDAR systems for simultaneous range-velocity sensing","authors":"Chunyu Hou ,&nbsp;Guohui Yuan ,&nbsp;Shichang Xu ,&nbsp;Zhirong Li ,&nbsp;Hongwei Zhang ,&nbsp;Junxiang Zhang ,&nbsp;Zhuoran Wang","doi":"10.1016/j.optlaseng.2025.109313","DOIUrl":"10.1016/j.optlaseng.2025.109313","url":null,"abstract":"<div><div>Frequency Modulated Continuous Wave (FMCW) LiDAR achieves simultaneous high-precision target measurement, offering inherent anti-interference capability and sub-millimeter stability for mission-critical applications. However, spectral aliasing caused by Doppler–range coupling in high-speed or short-range scenarios limits dynamic target detection and constrains measurable velocities. This work proposes a heterogeneous chirp modulation-based FMCW LiDAR system for simultaneous and unambiguous range and velocity measurement. It employs two independent lasers that generate a wideband triangular-chirp and a narrowband sawtooth-chirp optical signal, respectively. This modulation strategy produces multiple beat signals with distinct spectral separation, which establishes a deterministic mapping between range- and velocity-dependent components and enables their decoupling. As a result, the heterogeneous chirp architecture effectively resolves spectral aliasing and achieves robust, unambiguous sensing in high-dynamic scenarios. The system is first validated through MATLAB-based frequency-domain simulation and optical system modeling, followed by experimental evaluation under both typical and high-dynamic (short-range vibration and AOM-based high-speed simulation) motion. Under typical motion conditions, it achieves a range error below <figure><img></figure> and a velocity error below <figure><img></figure> across all tested conditions. In a near-range vibration experiment, it measures a distance of <figure><img></figure> and a velocity of <figure><img></figure>. By emulating Doppler shifts with an acousto-optic modulator (AOM), the system is further demonstrated to be capable of tracking high-speed motion up to <figure><img></figure> within a range of <figure><img></figure>, corresponding to approximately 20 times the upper velocity limit of conventional FMCW LiDAR under similar short-range conditions.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109313"},"PeriodicalIF":3.7,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental demonstration of 10 Gbps security-enhanced optical transmission link over turbulent atmosphere","authors":"Chao Chen,&nbsp;Yufeng Song,&nbsp;Jianhua Ji","doi":"10.1016/j.optlaseng.2025.109347","DOIUrl":"10.1016/j.optlaseng.2025.109347","url":null,"abstract":"<div><div>Physical layer security is a crucial research aspect for future optical transmission systems. This paper introduces a novel low-complexity two-stage composite encryption scheme with time-frequency scrambling, chaotic interpolation and permutation for differential free-space optical (D-FSO) systems. It also experimentally demonstrates for the first time that the scheme can enhance the physical layer security of <span>D</span>-FSO systems using 4-level pulse amplitude modulation (PAM4) technology. In the first stage, the grouped PAM4 mapping signals are encrypted using time-frequency scrambling, with different scrambling parameters for each group to enhance the security of the first stage. In the second stage, the scrambled signals undergo chaotic interpolation and permutation encryption in groups using one-dimensional Logistic map sequences, with each group's chaotic mapping and the dual links of the <span>D</span>-FSO system being independently encrypted to enhance the security of the second stage. Experimental results show that under various turbulence conditions, the proposed encryption scheme significantly enhances the security of a 10 Gbps <span>D</span>-FSO system. Compared to traditional FSO systems, the average received optical power gain is approximately 0.9 dBm, and the symbol error rate achieved by eavesdroppers remains above 0.6. Therefore, this presented scheme holds promising application prospects for future secure optical communication systems due to its superior reliability and security performance.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109347"},"PeriodicalIF":3.7,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser signal processing technology: a coaxial laser ranging module of light detection and ranging device","authors":"Jinlin Cui","doi":"10.1016/j.optlaseng.2025.109345","DOIUrl":"10.1016/j.optlaseng.2025.109345","url":null,"abstract":"<div><div>Light Detection and Ranging (LiDAR) devices are essential components in the fields of autonomous driving and drone environmental perception. Theoretically, coaxial laser ranging systems of LiDAR offer significant advantages, including high precision, lightweight design, and cost-effectiveness. However, practical applications have shown that coaxial systems often face challenges such as low energy utilization and suboptimal signal-to-noise ratios. In our previous work, we addressed the issue of energy efficiency. In this study, we successfully completed the trial production of consumer modules. By taking advantage of the characteristics of the laser beam within the optical system, we improved the signal-to-noise ratio through advanced photoelectric filtering techniques applied to the detector. Experimental results indicate that, without any algorithmic optimization of the original signal, the blind area of the laser ranging system has been reduced to 0.5 meters. This approach represents a cost-effective and efficient way to improve the performance of coaxial laser ranging devices.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109345"},"PeriodicalIF":3.7,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ measurement of single-nanoparticle refractive index via electrically modulated optical tweezers","authors":"Peng Chen ,&nbsp;Nan Li ,&nbsp;Peitong He ,&nbsp;Xingfan Chen ,&nbsp;Xincai Xu ,&nbsp;Dawei Wang ,&nbsp;Huizhu Hu","doi":"10.1016/j.optlaseng.2025.109331","DOIUrl":"10.1016/j.optlaseng.2025.109331","url":null,"abstract":"<div><div>Accurate measurement of the refractive index of nanoparticles is a core challenge in basic science and multi-disciplinary application. The current methods usually involve statistical analysis of the particle group, which reduces the measurement accuracy and ignores the individual characteristics. Based on the photomechanical regulation mechanism, the research constructed an optical tweezers and electric field synergistic platform, and realized the in-situ dynamic measurement of the refractive index of single- nanoparticles through the composite drive of periodic electric field and direct-current field. By driving the sensing unit to change the equilibrium position, the sub-wavelength size optical field is accurately measured, and the nanoscale physical information under the force equilibrium state is measured. This method is sensitive to the refractive index of typical particles such as SiO₂ and PS. It can distinguish different types of particles and different states of particles based on real-time detection of refractive index measurement, with a maximum standard deviation of 4.9 %.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109331"},"PeriodicalIF":3.7,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-step automated method for robust Fourier ptychographic microscopy LED misalignment calibration","authors":"Piotr Arcab,&nbsp;Mikołaj Rogalski,&nbsp;Maciej Trusiak,&nbsp;Piotr Zdańkowski","doi":"10.1016/j.optlaseng.2025.109340","DOIUrl":"10.1016/j.optlaseng.2025.109340","url":null,"abstract":"<div><div>This article introduces a fully automated and robust hardware calibration method for aligning the LED matrix in Fourier Ptychographic Microscopy (FPM). The proposed method is divided into two independent procedures targeting translational and rotational misalignments. Translational errors are corrected using the Automatic LED Calibration (ALC) metric, which evaluates the symmetry of Fourier spectra obtained from two images illuminated from opposite angles. Rotational misalignments are handled through a subpixel image registration algorithm that estimates direction and magnitude of the angular deviation. Neither step requires specialized calibration targets or complex modeling. Experimental results confirm that method reliably compensates for a wide range of misalignments, delivering stable and reproducible outcomes across diverse conditions and calibration objects. This dual-step approach significantly reduces alignment effort and improves the quality of image reconstruction. Once calibrated, the system enables high-fidelity reconstructions using both Quasi-Newton and Gerchberg-Saxton algorithms. The method is compatible with open-source platforms like FPMapp, streamlining its integration into existing workflows. By simplifying system alignment while maintaining precision, this calibration strategy is poised to accelerate the broader adoption of FPM in digital pathology and biomedical imaging. The proposed approach is presented as a step-by-step procedure suitable even for non-expert users, facilitating practical implementation across various applications.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"195 ","pages":"Article 109340"},"PeriodicalIF":3.7,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}