物理与天体物理最新文献

{"title":"High-efficiency polarization beam merging metagrating design via global initial solution-based topology optimization.","authors":"Zhiqiang Han, Yuhan Zheng, Mingfeng Xu, Si Wang, Mingbo Pu, Xiaoliang Ma, Yinghui Guo, Xiong Li, Xiangang Luo","doi":"10.1364/OL.557718","DOIUrl":"https://doi.org/10.1364/OL.557718","url":null,"abstract":"<p><p>Freeform metasurfaces based on topology optimization enable precise control over electromagnetic functionalities, with widespread applications in metagratings, metalenses, and polarization transformations. The selection of the initial structure plays a crucial role in determining the quality of the final optimization results. In this study, a global initial solution-based topology optimization (GISTO) is proposed to design a polarization beam merging metagrating efficiently. A two-dimensional encoded non-dominated sorting genetic algorithm II is employed for global exploration to obtain a high-quality initial structure, which is then refined using gradient-based topology optimization for a local optimization design. By integrating global and local optimization, the efficiency of polarization beam merging metagrating is significantly improved. Under symmetric incidence, the efficiencies for x-polarized and y-polarized beams reach 93.6% and 95.3%, respectively, while under asymmetric incidence, the efficiencies achieve 99.4% and 95.4%, respectively.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1637-1640"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528119","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":"Purity-based self-calibration in ptychography.","authors":"Chang Liu, Wilhelm Eschen, Daniel S Penagos Molina, Leona Licht, Mahmoud Abdelaal, Jan Rothhardt","doi":"10.1364/OL.543865","DOIUrl":"https://doi.org/10.1364/OL.543865","url":null,"abstract":"<p><p>Calibration of ptychographic setup properties, such as the sample-detector axial distance, is crucial for quantitative and high-resolution reconstructions. This study proposes a calibration scheme based on the degree of coherence (i.e., purity) of the probe in mixed-state ptychography. Compared to established sharpness metric-based methods, it is significantly more robust and applicable to arbitrary samples. A numerical study and validations with various experimental datasets have been conducted to verify the performance of the proposed method, including the application to high-contrast samples and weakly-scattering biological samples. This calibration scheme can significantly enhance the image quality, the precision of wavefront sensing, and the reliability of quantitative analysis for ptychography. Potentially, we believe this optimization method can find further applications in other areas of computational imaging.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1581-1584"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528152","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":"Ultrasensitive dynamic ultraviolet imaging based on a Ga₂O₃ photodetector array.","authors":"Tiwei Chen, Nan Liu, Suzhen Cheng, Xiaodong Zhang, Peng Ding, Chunhong Zeng, Li Zhang, Gaofu Guo, An Yang, Yu Hu, Zhucheng Li, Dengrui Zhao, Huanyu Zhang, Shige Dai, Jiawei Ye, Jingwu Gong, Zhanqiang Ru, Wenhua Shi, Zhongming Zeng, Helun Song, Baoshun Zhang","doi":"10.1364/OL.555862","DOIUrl":"https://doi.org/10.1364/OL.555862","url":null,"abstract":"<p><p>Defects and noise in Ga₂O₃ detectors have traditionally limited their practical application. In this work, by reducing the triethylgallium flow from 200 sccm to 50 sccm, oxygen vacancy was effectively suppressed, leading to a transition in noise from Lorentzian to flicker-type, with a significant decrease in noise current from 0.15 nA to 1.01 pA. This improvement enhanced the detector's performance, yielding high sensitivity (3.72 A/W), fast response time (<i>τ</i>_d1/<i>τ</i>_d2 = 1.6/13 ms), and solar-blind detection characteristics. Leveraging this low-noise detector, an 8 × 8 photodetector array and UV imaging system were developed, capable of target identification at distances up to 3 m, detecting UV radiation at intensities of 2.6 μW/cm², and capturing real-time spatial movement of point light sources. These advancements mark a significant contribution to the development of high-speed, high-sensitivity, solar-blind UV imaging systems.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1633-1636"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528166","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":"Low-loss and tight-bend waveguides via multiple scans of a femtosecond laser.","authors":"Kai-Heng Xiao, Yi-Hao Zan, Yang Ouyang, Si-Xue Fei, Zhi-Yong Hu, Li-Nan Fang, Zhen-Nan Tian, Qi-Dai Chen","doi":"10.1364/OL.551272","DOIUrl":"https://doi.org/10.1364/OL.551272","url":null,"abstract":"<p><p>In this paper, in situ multiple scans of a femtosecond laser are employed to optimize the refractive index distribution in a glass optical waveguide. The emergence of second bright core boundary (SBCB) and the increasing density of three- and four-membered rings in silica were thoroughly investigated. They can lead to a higher refractive index in a waveguide core and enhance the light confinement capability, which can increase the spatial integration density of bent waveguide structures. A 90° tightly bent single-mode waveguide is prepared at 808 nm, achieving a minimum bending loss of 1.028 dB/cm at a bending radius of 10 mm. This study will facilitate the preparation of on-chip large-scale, highly integrated photonic chips.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1449-1452"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528132","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":"Multi-megawatt pulses from 1030 to 1300 nm based on soliton self-frequency shifting in a nitrogen-filled fiber.","authors":"Yishai Eisenberg, Wenchao Wang, Yi-Hao Chen, Jose Enrique Antonio-Lopez, Rodrigo Amezcua-Correa, Chris Xu, Frank W Wise","doi":"10.1364/OL.551046","DOIUrl":"https://doi.org/10.1364/OL.551046","url":null,"abstract":"<p><p>Soliton formation and soliton self-frequency shift are investigated in a hollow-core fiber filled with N₂ gas. With 10-µJ and 80-fs input pulses at 1030 nm, solitons with greater than 500-nJ energy and duration less than 100 fs can be generated between 1090 and 1310 nm. With peak powers above 5 MW, we expect that these pulses will be useful for applications such as nonlinear microscopy.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1593-1596"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528137","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":"Rapid configuring method for a programmable photonic integrated circuit based on a tandem neural network.","authors":"Zeyang Fan, Yihang Dan, Junmin Lin, Tian Zhang, Jian Dai, Kun Xu","doi":"10.1364/OL.551119","DOIUrl":"https://doi.org/10.1364/OL.551119","url":null,"abstract":"<p><p>Programmable photonic integrated circuits (PPICs), as optical analog matrix multipliers, emerge as a leading candidate of a revolutionary technology. However, the efficient voltage configuration of programmable devices in the circuit presents a significant challenge to its development. Here, we propose a black-box method based on tandem neural network to rapidly predict the voltage configuration of arbitrary matrices. We experimentally demonstrate the feasibility of our method on a 4 × 4 PPIC, achieving the average fidelity of 0.989 for 10,000 matrices. Furthermore, we experimentally implement an optical-electric hybrid model based on our method, obtaining a training accuracy of 97.59% on the MNIST dataset.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 5","pages":"1731-1734"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528154","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":"Gravitational wave emission in binary neutron star early post-merger within a dark environment","authors":"D. Suárez-Fontanella,&nbsp;D. Barba-González,&nbsp;C. Albertus,&nbsp;M. Ángeles Pérez-García","doi":"10.1016/j.physletb.2025.139358","DOIUrl":"10.1016/j.physletb.2025.139358","url":null,"abstract":"<div><div>Using an effective Lagrangian model inspired by Takami et al. <span><span>[1]</span></span> we qualitatively study the early post-merger of a nearly symmetric binary Neutron Star (BNS) merger event with a non-vanishing ambient fraction of dark matter. For this we first mimic the dynamics of two oscillating Neutron Star (NS) masses in the gravitational potential well as they merge. We parametrize the dynamics and ejecta properties in the coalescence event allowing the formation of a surrounding debris disk that may be containing a non-vanishing dark matter fraction. In order to analyze the possible novel dark contribution, we start from a dark-matter free modelization as a benchmark. Using Monte Carlo Markov Chain (MCMC) techniques we approximately recover the gravitational waveforms, restricted to early post-merger time interval from existing simulations in the CoRe database. Later, we explore the impact of an additional dark viscous fluid under a prescribed velocity dependent force in the Lagrangian and obtain the resulting waveforms and some spectral features originating in the first few ms in the BNS post-merger. Finally we discuss our qualitative findings and its range of validity in light of the prospects of detectability in present or future experimental settings.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"862 ","pages":"Article 139358"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvement of microstructure and mechanical properties of Inconel718 by the synergistic strategy of laser power and interlayer temperature control in laser directed energy deposition","authors":"Siwei Xin ,&nbsp;Defu Liu ,&nbsp;Xingyu Li ,&nbsp;Xuyu Pi ,&nbsp;Guan Liu ,&nbsp;Zixin Deng ,&nbsp;Tao Chen","doi":"10.1016/j.optlastec.2025.112715","DOIUrl":"10.1016/j.optlastec.2025.112715","url":null,"abstract":"<div><div>This paper addresses common issues such as microstructure defects, columnar grains, and elemental segregation in Laser Directed Energy Deposition (LDED) of Inconel718 superalloy thin-walled components. A novel synergistic control strategy for the LDED process is proposed. This strategy involves decreasing the input laser power layer by layer and forcibly lowering the interlayer temperature with forced air cooling, aiming to improve the microstructure and mechanical properties of Inconel718 superalloy thin-walled components. The research results show that compared with the traditional LDED process, the LDED process using the novel synergistic control strategy enhances the stability of the molten pool in each deposition layer, maintains the constant width of each deposition layer, significantly reduces porosity, and improves the material density of the components. Under the synergistic strategy, discrete fine Laves phases, as well as a mixed structure of disorderly grown fine columnar grains and equiaxed grains, were formed in the Inconel718 thin-walled components. These improvements in microstructure have led to an increase in the microhardness, tensile strength, yield strength, and elongation of the components by 9.30%, 41.12%, 26.05%, and 40%, respectively. Further analysis of the porosity, grain morphology, and distribution of Laves phases in the components reveals the strengthening mechanism of the new synergistic strategy proposed in this paper. The reasons for the improvement in tensile properties include HAGB (High Angle Grain Boundary) strengthening, LABG (Low Angle Grain Boundary) strengthening, dislocation strengthening, pore healing, the formation of discrete fine Laves phases, and the reduction of polarization density. This study provides an effective technical approach for the LDED of high-performance Inconel718 superalloy thin-walled components.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"186 ","pages":"Article 112715"},"PeriodicalIF":4.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520188","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":"Power efficiency comparison for various MIM tile structures of fully integrated two-phase 2:1 SCVR for photovoltaic applications","authors":"Sunita Saini,&nbsp;Davinder Singh Saini","doi":"10.1016/j.optlastec.2025.112701","DOIUrl":"10.1016/j.optlastec.2025.112701","url":null,"abstract":"<div><div>Fully integrated switched capacitor voltage regulators are evolved as promising devices for solar photovoltaic systems as they can efficiently convert one voltage level into another. This work introduces a novel approach for enhancing the power efficiency of fully integrated switched capacitor voltage regulators specifically designed for solar photovoltaic systems. A general steady-state performance model of switched capacitor converter is investigated using charge-multiplier approach. In order to improve the converter efficiency in the presence of parasitic losses, the basic<!--> <!-->switched capacitor converter analysis is extended to incorporate expressions for the lowest attainable power loss using on-die high-density capacitor. The novelty of this study lies in the investigation of integrated metal–insulator-metal capacitors with various tile structures, which are utilized to realize compact, fully integrated DC-DC converters with enhanced efficiency for photovoltaic applications. This work presents a comparative study of different MIM capacitor tile structures of a two-phase 2:1 series–parallel converter operating at an input voltage of 1.24 V. The efficiency of these structures is evaluated by considering various factors, including the impact of switch and pre-driver parasitic. The analysis is done to optimally select the component values, switch size, capacitance and switching frequency for a two-phase 2:1 series–parallel converter implemented in 22 nm tri-gate process technology. Through a comprehensive set of cross-corner PSpice simulations, the impact of different MIM capacitor tile structures on converter efficiency is investigated at current densities of 400 mA/mm² and 650 mA/mm², respectively. The results shows that MIM tile1 (corresponding to the core height) exhibits approximately 0.5 % lower efficiency than MIM tile2 (corresponding to half of the core height) at the lower current density of 400 mA/mm², with a slightly larger efficiency reduction of about 1 % observed at the higher current density of 650 mA/mm². The results are validated using MATLAB and PSpice simulation tools.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"186 ","pages":"Article 112701"},"PeriodicalIF":4.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520288","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":"Nonclassicality and Sub-Planck Structures of Photon Subtracted Compass States","authors":"Amit Das,&nbsp;Sobhan Sounda","doi":"10.1007/s10773-025-05938-2","DOIUrl":"10.1007/s10773-025-05938-2","url":null,"abstract":"<div><p>We discuss the nonclassical properties of photon-subtracted compass states (PSCS). Nonclassical behavior is studied using various parameters like the Wigner function, squeezing, and photon statistical parameters like Mandel’s <i>Q</i>-function, second-order correlation function, Agarwal-Tara <span>(A_3)</span> criterion, and photon number distribution. Further analysis is being done to investigate the sub-Planck structures in the Wigner functions of these PSCS. We also show that the photon subtraction doesn’t cause the loss of sensitivity due to displacement of the states in phase space.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"64 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}