Optics and Laser Technology最新文献

{"title":"Core-cladding parallel FBG with enhanced SNR via direct femtosecond laser inscription","authors":"Koustav Dey,&nbsp;Ogbole Collins Inalegwu,&nbsp;Chen Zhu,&nbsp;Rex E. Gerald II,&nbsp;Jie Huang","doi":"10.1016/j.optlastec.2025.114019","DOIUrl":"10.1016/j.optlastec.2025.114019","url":null,"abstract":"<div><div>The signal-to-noise ratio (SNR) is a critical parameter influencing the performance of fiber Bragg grating (FBG)-based sensors, particularly in distributed sensing and harsh-environment applications. Enhancing the SNR is therefore essential for achieving repeatable, reliable and high-precision sensing. In this study, we present a novel approach based on evanescent wave coupling, wherein a cladding FBG is fabricated parallel to the primary core FBG at an offset of 2 µm from the core-cladding interface by utilizing the direct femtosecond (fs) laser inscription. This configuration significantly enhances the reflectivity of the sensing system. At the same time, it also preserves high spatial resolution and ensures minimal insertion loss (IL). The proposed method has demonstrated its effectiveness in enhancing reflectivity across FBGs with varying initial reflectivity levels, achieving a maximum improvement of approximately 700 % as reported in this study. This significant improvement is particularly beneficial for low-reflectivity FBGs utilized in a wider range of distributed sensing applications. Moreover, the sensor was subjected to temperature testing over a range of 25 °C–700 °C, followed by a long-term stability assessment conducted over an 18-hour period at 500 °C. The approach has also been successfully implemented in quasi-distributed sensing applications. Additionally, it has been demonstrated that the incorporation of cladding FBGs does not introduce any significant IL: four fabricated cladding FBGs showed maximum IL of ∼0.088 dB. This proposed method, therefore, holds significant potential and opens up a new avenue for improving the performance of low-reflectivity FBGs, enabling longer sensing ranges with minimal IL and improved measurement resolution, particularly in distributed sensing applications.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 114019"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct welding of glass and aluminum alloy using nanosecond fiber laser with beam oscillation","authors":"Jinming Ma ,&nbsp;Meng Jiang ,&nbsp;Xi Chen ,&nbsp;Ao Chen ,&nbsp;Xuan Su ,&nbsp;Yanbin Chen ,&nbsp;Peng He","doi":"10.1016/j.optlastec.2025.114011","DOIUrl":"10.1016/j.optlastec.2025.114011","url":null,"abstract":"<div><div>In this work, glass and aluminum alloy were directly welded using a novel process of nanosecond fiber laser with beam oscillation. The feasibility of achieving reliable joining of glass and aluminum alloy without surface polishing or external pressure was explored via changing the beam oscillation strategy. The results showed that a defect-free glass/aluminum alloy joint could be fabricated with a 40 μm lap gap using optimized parameters: a laser power of 25 W, a scanning speed of 50 mm/s, an oscillation frequency of 750 Hz, and an oscillation amplitude of 150 μm. The welded joints exhibited a maximum shear strength of 10.95 MPa, which is 6 times higher than that without beam oscillation. Fractographic analysis results showed that beam oscillation homogenized laser energy distribution, which could result in an uniform melting and intermixing of glass and aluminum alloy. The enhanced strength of the weld joint was attributed to the improved mechanical interlocking and reduced cracks in the glass modification zone. This work presents a reliable approach for the direct joining of glass and aluminum alloy without the need for surface polishing or external pressure, ensuring high welding efficiency.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 114011"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Packaged ultrahigh-Q silica hollow microrod WGM resonator with simplified modes for nonlinear photonics","authors":"Zhaofeng Kang ,&nbsp;Binbin Yang ,&nbsp;Jiacheng Liu ,&nbsp;Yang Wang ,&nbsp;Di Tang ,&nbsp;Lei Zhang ,&nbsp;Keyi Wang ,&nbsp;Yu Yang","doi":"10.1016/j.optlastec.2025.113981","DOIUrl":"10.1016/j.optlastec.2025.113981","url":null,"abstract":"<div><div>This study analyzed the influence of resonator edge curvature on resonator modes, improved the processing technology for producing silica microrod resonators via CO₂ lasers, and developed a hollow microrod resonator with an ultrahigh <em>Q</em>-factor. Simulation results showed that reducing the axial width of the resonator and increasing the axial cross-sectional curvature effectively suppressed the generation of high-order axial modes in the resonator. The edge morphology of the resonator could be easily controlled because of the improved processing technology, and hollow microrods with an ultrahigh <em>Q</em>-factor could be produced. A package that could effectively couple the microrod resonator with tapered fiber for long-term stability was also designed. In addition, the generation of Kerr–Raman combs was demonstrated using the packaged microrod resonator. Experimental results demonstrated that the microrod resonator had an ultrahigh <em>Q</em>-factor and a concise mode. It is expected to play an important role in various nonlinear photonics applications, such as optical frequency comb generation and quantum information.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 113981"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wavelength-tunable fiber comb filter with wide bandpass characteristics based on a first-order polarization-diversified loop","authors":"Yong Wook Lee ,&nbsp;Jaehoon Jung","doi":"10.1016/j.optlastec.2025.114013","DOIUrl":"10.1016/j.optlastec.2025.114013","url":null,"abstract":"<div><div>For the first time, a novel design methodology is presented for the wide bandpass transmittance function (WBTF), enabling spectral bandwidth extension by controlling the incident state of polarization on the second polarization-maintaining fiber segment in a first-order fiber comb filter based on a polarization-diversified fiber loop configuration. An analytical expression for the final transmission spectrum is derived as a function of the design parameter, and the feasibility of continuous wavelength tunability is verified through both theoretical analysis and experimental validation. A closed-form transmittance expression for arbitrary phase shifts is also formulated, allowing direct determination of suitable waveplate orientation angles via numerical evaluation and eliminating exhaustive angular searches. The proposed angular search procedure identifies 360 distinct waveplate orientation sets, each corresponding to a 1° incremental phase shift over the full 0°–360° range, confirming the WBTF’s tunability. Eight wavelength-shifted spectra corresponding to specific phase shifts of 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° are computed, demonstrating that deliberate waveplate angle selection enables continuous wavelength tuning. Experimental measurements validate the predicted frequency tuning, confirming the practical feasibility of the mechanism. To the best of our knowledge, this work presents the first spectral bandwidth design that enhances filter performance by manipulating the polarization trajectory in a first-order filter based on polarization-diversified fiber loop, offering a versatile approach for advanced optical filtering applications.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 114013"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operando monitoring of battery state-of-charge via tilted fiber Bragg grating cascaded with chirp fiber Bragg grating using integrated area method","authors":"Tingting Gang ,&nbsp;Shanshan Fu ,&nbsp;Xiaomeng Xu ,&nbsp;Qimeng Lin ,&nbsp;Chun Zhang ,&nbsp;Qian Zhang","doi":"10.1016/j.optlastec.2025.114029","DOIUrl":"10.1016/j.optlastec.2025.114029","url":null,"abstract":"<div><div>An in situ optical sensing method, which is based on a cascaded tilted fiber Bragg grating and chirped fiber Bragg grating (TFBG-CFBG) configuration, is proposed and experimentally demonstrated for monitoring the electrolyte status of the lead-acid batteries. In the proposed system, the TFBG is embedded within the battery to monitor variations in the refractive index (RI) of the electrolyte, whereas the CFBG, placed externally, functions as a spectral filter. The reflected optical signals from both gratings are captured and subsequently measured using an optical power meter (OPM). During battery charging and discharging, changes in the electrolyte concentration alter the RI, thereby modifying the degree of spectral overlap between the TFBG and CFBG, which in turn leads to changes in the reflected power. Experimental results demonstrate that the real-time monitoring of electrolyte dynamics can be achieved by adopting an integrated area interrogation technique, while temperature interference within the range of 22 ℃–60 ℃ is significantly reduced. This study provides an optical sensing strategy for investigating battery reaction kinetics and for dynamically enhancing state-of-charge (SOC) monitoring through the use of compact and cost-effective instrumentation.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 114029"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Opto-thermomechanical microfluidics: hybrid optical trapping and photothermal convection for multiscale particle manipulation","authors":"Bingjie Li ,&nbsp;Weitao Dai ,&nbsp;Yiwen Yang ,&nbsp;Xu Xia ,&nbsp;Zhishan Hou ,&nbsp;Wei Xue ,&nbsp;Yu Cao","doi":"10.1016/j.optlastec.2025.113995","DOIUrl":"10.1016/j.optlastec.2025.113995","url":null,"abstract":"<div><div>An optofluidic chip with integrated dual-mode optical manipulation is proposed by us, combining scattering force-driven propulsion with photothermal-induced convection. By embedding twelve functionalized fibers—eight dedicated to optical forces and four to optothermal actuation—the platform enables long-range (972 μm) and high-speed (72 μm/s) particle control, exceeding the limited working distance (&lt;200 μm) of conventional optical tweezers. This hybrid mechanism facilitates multiscale operations, ranging from single-particle translocation to the collective migration of particle assemblies, with sub-micron precision. Experimental and simulation results reveal size-dependent particle dynamics under varying laser powers and channel geometries. This low-cost, modular design opens avenues for on-chip biosensing and micro-robotic systems, as validated by applications in particle sorting, patterning, and transport.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 113995"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization and optimization of the low-toxicity nanocomposite photopolymer Biophotopol for holographic couplers","authors":"J.J. Sirvent-Verdú ,&nbsp;J.C. García-Vázquez ,&nbsp;J.C. Bravo ,&nbsp;J. Ferrández ,&nbsp;C. Neipp ,&nbsp;S. Gallego ,&nbsp;A. Beléndez","doi":"10.1016/j.optlastec.2025.113946","DOIUrl":"10.1016/j.optlastec.2025.113946","url":null,"abstract":"<div><div>In this work, we aim to study and exploit the photosensitivity properties of a low-toxicity photopolymer Biophotopol for the manufacturing of holographic couplers for see-through applications. The different geometries used to record such holographic gratings, both in transmission and reflection schemes, are explained. In our proposal, no prisms or index matching systems are used in the recording geometry, thanks to the wavelength shift between the recording and reconstruction steps. Moreover, the material’s composition is optimized and characterized for different recording schemes. We provide experimental evidence that the holographic optical elements maintain their designed properties by allowing the diffracted beam to propagate under Total Internal Reflection at the Bragg condition. The shrinkage present in this material is overcome by including a cross-linker monomer and Pt nanoparticles, while also increasing the average refractive index modulation of the holograms. This effect also causes the recording light to be coupled within the system, providing a single coupler that can guide different wavelengths.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 113946"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Si-based amorphous SnO2 vertical heterojunction photodetectors with high responsivity and nanosecond photoresponse","authors":"Can Zhang ,&nbsp;Hongyan Yin ,&nbsp;Sui Mao ,&nbsp;Dongyang Li ,&nbsp;Hao Jing ,&nbsp;Xuelei Cao ,&nbsp;Peng Liu ,&nbsp;Enze Li ,&nbsp;Junwei Nan ,&nbsp;Peter Strizhak ,&nbsp;Linjun Huang ,&nbsp;Jianguo Tang","doi":"10.1016/j.optlastec.2025.113930","DOIUrl":"10.1016/j.optlastec.2025.113930","url":null,"abstract":"<div><div>Photodetectors play a crucial role in the field of optoelectronic communications and other information-related domains. Si as one of the most important materials for visible light detection, has its performance constrained by factors such as its low absorption coefficient, which limits the further enhancement of commercial photodetector performance. In this work, by employing a SnO₂ heterojunction, we have fabricated a MSM structured photodetector with a vertical PN space charge region. The photoelectrons generated in the space charge region can be accelerated onto the SnO₂ surface and achieve sensitive spectral response. By varying the thickness of SnO₂, the thickness of the space charge layer in the detector is gradiently modulated. Together with the photo-induced potential from KPFM characterization, the key role of the space charge layer thickness is fully confirmed in performance modulation of devices. The device achieves a maximum responsivity of 0.65 A/W and a quantum efficiency of 94.6 %. More notably, the transient response of the device is below 20 ns, demonstrating the application potential of this structure in photodetectors.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 113930"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving mechanical properties of the Al–Si coated press-hardened steel self-fusion joint by utilizing dual-beam laser welding","authors":"Yanjie Sun ,&nbsp;Y.J. Wang ,&nbsp;X.Z. Zhang ,&nbsp;S.L. Yang ,&nbsp;F.L. Jiang","doi":"10.1016/j.optlastec.2025.114026","DOIUrl":"10.1016/j.optlastec.2025.114026","url":null,"abstract":"<div><div>The Al–Si coated press-hardened steels (PHS) are increasingly used in the automotive industry, but their welding properties are significantly degraded due to frequent melting of the Al–Si coating into the molten pool. Al in the coating melts into the weld and undergoes local enrichment, inducing the formation of <em>δ</em>-ferrite in this region. The interface between such <em>δ</em>-ferrite and martensite acts as a crack initiation site, leading to premature weld fracture, which necessitates either removing the Al–Si coating before laser welding or adding filler wire during welding to dilute the Al content. In this study, a laser processing head with a beam splitting device was used to split a laser beam generated into two serially arranged beams for welding. Without removing the coating or adding additional filler wire, the mechanical properties of the laser-welded joints of the new thin-coated PHS have reached a level comparable to those of the base metal. The microstructure, fracture morphology, dynamic behavior, and morphological evolution of the molten pool under different welding conditions were investigated. The results showed that dual-beam laser welding with a spot spacing of 490 μm achieved an elongation of 9.21 %, representing an increase of 52.43 % compared with single-beam laser welding joints (5.67 %), and the tensile strength was almost identical to unwelded base metal. As the spot spacing increased, the joint elongation decreased gradually. In the fusion zone of single-beam joints, long and wide strips of <em>δ</em>-ferrite were observed, which contributed to brittle fracture and low elongation. As the spot spacing increased from 0 μm to 490 μm, 1000 μm, and 1500 μm, the area ratio of these <em>δ</em>-ferrite to martensite in the fusion line region is 6.84 %, 0 %, 0.56 %, and 2.55 %, respectively. The average grain size in the fusion line region of the single-beam joint was 8.13 μm, which was reduced to 7.79 μm in the dual-beam joint. The morphological characteristics of the molten pool and keyhole in top-view and longitudinal section were captured in real-time using a high-speed camera in combination with the “sandwich” welding method. The results demonstrated that the dual-beam laser enlarged the length and width dimensions of the melt pool by more than 15 % compared with the single-beam laser, and intensified melt flow within the pool, effectively suppressing macroscopic segregation of Al.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 114026"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of 100 kHz femtosecond laser continuous scanning welding and spot welding of glass and aluminium film","authors":"Hongrui Wang,&nbsp;Wenchao Zhong,&nbsp;Zizheng Zhao,&nbsp;Bowen Liu,&nbsp;Dongqing Pang,&nbsp;Minglie Hu","doi":"10.1016/j.optlastec.2025.113969","DOIUrl":"10.1016/j.optlastec.2025.113969","url":null,"abstract":"<div><div>In this paper, we studied the femtosecond laser welding of soda–lime–silicate glass and a pure aluminium film by employing a 100 kHz femtosecond laser. The morphology of the whole welding region is the same as that of the glass. The sizes of the defects in the welding regions must be very small, so that it looks like that the welding region integrates seamlessly with the glass. However, the real profile of the welding region can be still plotted after analyzing the SEM-EDS data and the Raman data. The welding region can be divided into three major parts: the area formed from the solidifying plasma of aluminium, from the solidifying mixed plasma of two materials, and where the silicate networks are partly destroyed, respectively. This means that the material properties in the welding region gradually transform from ductile to brittle towards the beam. We also studied two types of welding, continuous scanning welding and spot welding, and the lap shear strengths are compared in the different total areas of the welds. The data show that both types of the laser welding can provide strong strength. We attribute the high strength to the density of the welding region which results from a step welding dynamics caused by a relatively low repetition rate and a relatively high intensity.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"192 ","pages":"Article 113969"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}