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Transmitter diversity and OAM incorporated 40 Gbps free space optical system

Journal of optical Communications 2025年第2期46卷 445-456页

作者： Singh, Somdeep Singh, Preeti Kaur, Pardeep University Institute of Engineering and Technology Panjab University Chandigarh India Electronics and Communication Engineering University Institute of Engineering & Technology Chandigarh India

The present research evaluates optical angular momentum's (OAM) performance in challenging atmospheric conditions and emphasizes its significance in free space optical (FSO) communication systems. It has been demonstrated that implementing the transmitter diversity (TD) technique effectively suppresses inter-channel interference, improving system performance as a whole. The best option among the studied encodings is found to be the combination of non-return-to-zero (NRZ) and carrier suppressed RZ (CSRZ), which performs better in a variety of weather scenarios and covers a wide FSO range from 72 m to 1450 m. Proposed system offered distance enhancement of 81.25 % under clear sky, 16.66 % under light rain, 10.22 % under moderate rain, 3.4 % under heavy rain, 10 % under light haze, 4 % under moderate haze, 4.44 % under heavy haze, 12.5 % under light fog, 4 % under moderate fog, 7.8 % under heavy fog, 5.8 % under light dust, 7.6 % under medium dust and 12.5 % under heavy dust as compared to existing workIn particular, during bad weather, this research offers significant insights into the design and optimisation of high-speed FSO systems. © 2024 Walter de Gruyter GmbH, Berlin/Boston.

关键词： Fog

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optical Software-Assisted design and Optimization of Bessel Beam systems for applications to laser materials processing 9

Optical Software-Assisted Design and Optimization of Bessel ...

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Conference on optical design and engineering IX

作者： Froehly, L. Hassan, M. Belloni, V Meyer, R. Furfaro, L. Giust, R. Courvoisier, F. Univ Franche Comte CNRS UMR 6174 Inst FEMTO ST F-25000 Besancon France

ISBN: (纸本)9781510673571;9781510673564

Bessel beams, known for maintaining focus over long distances, find many applications in imaging, nonlinear optics and laser material processing. For these applications, generating sub-micrometer Bessel beams is essential, but requires complex optical systems. Traditional optical software, designed for ray tracing, are challenged for this task. Here we show how we can use optical software to create and optimize optical design to generate these unconventional beams. The research involves high numerical aperture systems, investigates the influence of polarization, and the use of diffractive optical elements. Numerical findings are compared to experimental results, highlighting the potential of software-assisted beam design for various applications.

关键词： Bessel beams Laser ablation optical system ZEMAX OpticStudio@ANSYS

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Force-compensation-based adaptive thermal shape correction method for XFEL optics

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OPTICS EXPRESS 2024年第24期32卷 43118-43133页

作者： Liu, Jiayin Xu, Zhongmin Zhu, Ye Zhang, Weiqing Yan, Xinxin Qin, Hongliang Inst Adv Sci Facil Shenzhen 518107 Guangdong Peoples R China Chinese Acad Sci Dalian Inst Chem Phys Dalian 116023 Liaoning Peoples R China Univ Sci & Technol China Natl Synchrotron Radiat Lab Hefei 230029 Anhui Peoples R China

With the successive development of free electron laser (FEL) facilities based on superconducting technology, the advance and diversity of beamline optical design have posed more stringent challenges to the controlling of thermal deformation for key optical elements. In this article, an adaptive thermal shape correction structure is presented, which converts the thermal stress into a bending moment to correct the mirror thermal bump by utilizing the difference in coefficient of thermal expansion (CTE) between materials, and the location relative to the mirror neutral plane. This moment is involved owing to the temperature rise derived from the FEL heat load, which has a certain adaptability to various thermal surface profile and can be precisely controlled by a chiller temperature regulation. In this work, we optimize the dimensions and position of the thermal shape correction blocks by analytical method and FEA simulation respectively. Eventually, this force-compensation-based adaptive scheme can achieve sub-nano sensitivity (similar to 0.1 nm) of mirror shape control, considering factors such as ease of engineering implementation and operational feasibility, even under repetition rates up to 100 kHz.

关键词： Free electron lasers optical design and fabrication optical elements optical systems Photon counting Ultrashort pulses

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Demonstration of unified metalens workflow through design and manufacture of example eye-tracking meta-optic 6

Demonstration of unified metalens workflow through design an...

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6th Conference on optical Architectures for Displays and Sensing in Augmented, virtual, and Mixed Reality-AR, VR, MR

作者： Bacon-Brown, Daniel Leportier, Thibault Williams, Brad George, Matthew Gangadhara, Sanjay McGuire, Dylan Moxtek Inc 452 W 1260 N Orem UT 84057 USA Ansys Inc 10230 NE Points DrSuite 500 Kirkland WA 98033 USA

ISBN: (纸本)9781510686069;9781510686076

Metalenses and other metasurfaces are now established in academic settings and are approaching adoption in commercial applications. One of the major challenges in further development in this area is the coordination of system design with component design and manufacturing. There has been a significant communication gap between the optical systems designers who work with ray-tracing software, component designers who work with phase-profiles calculated with full-wave optical simulations, and metasurface manufacturers who work to turn the designs into actual elements. The need to perform this communication while also ensuring that the details of each organization's plans and methods are kept secret is challenging. Moxtek is collaborating with Ansys to bridge these gaps to establish a robust workflow that will allow optical systems designers to easily optimize a metasurface to maximize optical performance and be confident that the design is suitable for manufacturing. We demonstrate this workflow by walking through the design, layout, manufacturing, and metrology of an eye-tracking system for XR devices. This metalens was designed with ray-tracing software to have imaging properties that are difficult to create by conventional metalens design methods. The layout file was created using the manufacturer's established geometries that are known to be suitable for mass-production, which enabled the manufacturer to follow their own best-practices during the manufacturing process. Simulations were performed to predict the performance of the optic in a wafer-scale metrology tool, allowing a 1-to-1 comparison of simulation and metrology. Finally, the meta-optic was incorporated into a complete eye-tracking system and the performance of the complete system compared to the initial design.

关键词： metalens metasurface metastructure nanoimprint lithography eye-tracking metalens manufacturing volume manufacturing metalens metrology

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Influence of point cloud filtering on optical inspection of additive manufactured metal parts

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PRECISION engineering-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION engineering AND NANOTECHNOLOGY 2024年 90卷 12-20页

作者： Giganto, Sara Martinez-Pellitero, Susana Meana, victor Cuesta, Eduardo Barreiro, Joaquin Univ Leon Area Mfg Engn Campus Vegazana S-N Leon 24071 Spain Univ Oviedo Dept Construct & Mfg Engn Campus Gijon Gijon 33204 Spain

The characteristics of additively manufactured parts (topological optimisation, freedom of design ...) present a challenge from a metrological point of view. In this respect, non-contact inspection is of great importance for the rapid verification of this type of parts. However, their particular characteristics (stair-effect, high roughness, surface finish) can contribute to measurement errors and deviations when using different optical inspection equipment. In relation to this, 3D scanning point-clouds filtering can improve the results by increasing precision during inspection. In particular, this paper evaluates the influence of applying filters to digitize additive manufactured metal parts, which are scanned using different optical inspection systems commonly used in industry (based on laser triangulation, conoscopic holography and structured light techniques). The main objective is to establish the most suitable inspection procedure depending on the inspection system used. According to the dimensional results achieved, it can be concluded that the filtering does not have significant influence, regardless of the used sensor. However, the geometrical results are strongly influenced by the point-cloud quality;consequently, it is recommended to apply filters for most of the evaluated optical systems. One of the main contributions of this study is the definition of the filtering process methodology prior to non-contact inspection, depending on both the used optical system and the part to be evaluated, in order to define the most suitable filtering parameter to achieve a precise optical inspection.

关键词： optical measuring systems Non-contact inspection Point cloud filtering Metrological evaluation 3D scanning Metrological software filters Geometrical and dimensional analysis Metal additive manufacturing

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Inverse-designed 3D Laser Nanoprinted Phase Masks to Extend the Depth of Field of Imaging systems

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ACS PHOTONICS 2024年第9期11卷 3765-3773页

作者： Sturges, Thomas Jebb Nyman, Markus Kalt, Sebastian Palsi, Kauri Hilden, Panu Wegener, Martin Rockstuhl, Carsten Shevchenko, Andriy Karlsruhe Inst Technol KIT Inst Nanotechnol D-76131 Karlsruhe Germany Karlsruhe Inst Technol KIT Inst Appl Phys APH D-76131 Karlsruhe Germany Aalto Univ Dept Appl Phys FI-00076 Aalto Finland

In optical imaging, achieving high resolution often comes at the expense of a shallow depth of field. This means that when using a standard microscope, any minor movement of the object along the optical axis can cause the image to become blurry. To address this issue, we exploit inverse design techniques to optimize a phase mask which, when inserted into a standard microscope, extends the depth of field by a factor of approximately four without compromising the microscope's resolution. Differentiable Fourier optics simulations allow us to rapidly iterate toward an optimized design in a hybrid fashion, starting with gradient-free Bayesian optimization and proceeding to a local gradient-based optimization. To fabricate the device, a commercial two-photon 3D laser nanoprinter is used, in combination with a two-step precompensation routine, providing high fabrication speed and much better than subwavelength accuracy. We find excellent agreement between our numerical predictions and the measurements upon integrating the phase mask into a microscope and optically characterizing selected samples. The phase mask enables us to conduct simultaneous multiplane imaging of objects separated by distances that cannot be achieved with the original microscope.

关键词： optical imaging depth of field phase mask inverse design 3D laser nanoprinting

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Numerical optimization of auxiliary biaxial receiver to detect blind zone of pulsed coherent wind lidar

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OPTICS EXPRESS 2024年第7期32卷 12800-12815页

作者： Zhao, Mingguang Yu, Zhibin Wang, Huaijin Li, Mengpei Harbin Inst Technol Shenzhen Inst Space Sci & Appl Technol ISSAT Shenzhen 518055 Peoples R China Harbin Inst Technol Inst Space Sci & Appl Technol Shenzhen Key Lab Numer Predict Space Storm Shenzhen 518055 Peoples R China

The conventional pulsed monostatic coaxial coherent Doppler wind lidar (CDWL) has a blind detection zone of tens of meters, causing the loss of near-field wind field data. While maintaining the long-range detection capabilities of pulsed lidar, we introduce a novel auxiliary biaxial receiver (ABR) aimed at acquiring dependable coherent signals within blind zones. This is achieved by incorporating a receiver in close proximity to the monostatic coaxial transceiver (MCT), thereby mitigating end-face reflections and laser pulse tailing effects. A specific model of multiple aperture coherent wind detection is established for the ABR system without blind zone problem (BZP). The numerical simulations demonstrate that the biaxial receiver with reasonable design can meet the detection needs of the entire range of the blind zone. By using an ABR with a smaller focal length under appropriate transceiver pointing and general pointing accuracy, the BZP can be solved. The study also exhaustively obtained all parameter combinations that can solve the near-field BZP for a specific system. The results provide a new idea and engineering design guidance for the optical system design of pulsed CDWL without BZP.

关键词： Coherent systems Heterodyne detection Numerical simulation optical systems Polarization control systems design

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A new approach to chromatic variations of Seidel coefficients 9

A new approach to chromatic variations of Seidel coefficient...

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Conference on optical design and engineering IX

作者： Ochse, Dennis JENOPT Opt Syst GmbH Goeschwitzer Str 25 D-07745 Jena Germany

ISBN: (纸本)9781510673571;9781510673564

For the design of well corrected optical systems with a certain spectral bandwidth, it is often not sufficient to only control axial and lateral color, but also chromatic variations of the fourth order wave aberrations or Seidel coefficients need to be considered. This has already been studied in detail in the literature by Berner. We propose a different approach to calculate the induced surface contributions to chromatic variations of the Seidel coefficients, which is based on the principles of stop and object shift. This offers a different perspective that might be helpful for optical designers. Furthermore, it is demonstrated how this approach generalizes to other cases of tolerance sensitivities of rotationally symmetric systems.

关键词： optical design aberration theory spherochromatism stop shift object shift tolerance sensitivities

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Modeling extended L-band fiber amplifiers using neural networks trained on experimental data

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OPTICS EXPRESS 2024年第9期32卷 16182-16198页

作者： Rabbani, Hamed Jalilpiran, Saber Monga, Kaboko Jean-Jacques Larochelle, Sophie Rusch, Leslie a. Univ Laval Ctr Opt Photon & Lasers ECE Dept Quebec City PQ Canada

Producing high performance amplifiers requires accurate numerical models. As the optimization space is large, computationally efficient models are of great value. Parameter -based models for L -band amplifiers have accuracy limited by difficulty in estimating the Giles -parameter. The use a neural network model can avoid parametrization. We exploit a rich, experimentally captured training set to achieve a high accuracy neural network model. Our approach creates independent models for gain and noise figure. We examine both core and cladding pumping methods, again with independent models for each. The neural networks outperform parameterbased models with higher accuracy (variance of error reduced by 50%) and extremely fast simulation times (400 times faster), greatly facilitating amplifier design. As an example application, we design an amplifier to optimize optical signal-to-noise ratio by exhaustive search with our fast neural network models. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： Erbium fibers Machine learning Neural networks optical amplifiers optical signal to noise ratio optical systems

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Density functional theory-based strain engineering of electronic optical and thermoelectric properties of A2OX (A = Ga, in and X = S, Se) monolayers

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APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 2024年第6期130卷 456-456页

作者： Khan, Fawad Ahmad, Iftikhar Amin, Bin Ilyas, Muhammad Khalid, Sidra Fatima, Misbah Anwar Gomal Univ Inst Phys Dera Ismail Khan 29220 Khyber Pakhtunk Pakistan Univ Malakand Dept Phys Chakdara 18800 Pakistan Abbottabad Univ Sci & Technol Dept Phys Abbottabad Pakistan

The realization of Janus monolayers presents an exciting opportunity to disrupt structural symmetry, opening up novel avenues in the realm of layered materials. While several ternary systems, comprising the group-III monochalcogenides, has been proposed for this purpose, the impact of oxygen interaction on the electronic, thermoelectric and optical characteristics of gallium and indium monochalcogenides has been observed. Interestingly, the concept of incorporating oxygen as a third element in ternary systems has not yet been explored extensively. Here we embark on the design and exploration of 2D A(2)OX (A = Ga, In and X = S, Se) monolayer through first-principles calculations. Our investigation includes the analysis of electronic band structure, optical and thermoelectric properties, revealing that Ga2OS, Ga2OSe and In2OS exhibit direct band nature. However, In2OSe is found to be metallic in unstrained condition. Moreover, the band gap in these materials can be fine-tuned through the application of tensile or compressive strain. Additionally, our analysis suggests strong optical absorption within the visible, and/or ultraviolet regions, depending on the specific system under consideration. Our findings reveal that Ga2OS and In2OS monolayers elevated power factors with application of tensile strain, rendering them as compelling candidates for applications in thermoelectric devices.

关键词： Monolayers

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