Pub Date : 2024-03-22DOI: 10.1038/s44172-024-00198-0
Yongjian Tan, Jianyu Wang, Jincai Wu, Zhiping He
Polarization drift in fiber and free-space optical links is a major factor in the dynamic increase of bit error rate in polarization-coded quantum key distribution (QKD) systems. A dynamic polarization compensation method applicable to both links is a challenge. Here we propose a universally applicable real-time polarization compensation method, that the Muller parameters of the optical links are first detected using a polarization detector, and then the optimal parameters of the controller are obtained by gradient descent algorithm. Simulation results indicate advantages over current methods, with fewer waveplates, faster speed, and wider applicability for various optical links. In equivalent experiments of both satellite and fiber optical links, the average polarization extinction ratio of 27.9 dB and 32.2 dB are respectively achieved. The successful implementation of our method will contribute to the real-time polarization design of fiber and free-space QKD systems, while also contributing to the design of laser-based polarization systems. Yongjian Tan and colleagues report a universally applicable real-time polarization compensation method for quantum communications. The approach has several advantages over current methods, including a minimum number of waveplates, faster speed, and wider applicability for various optical links.
光纤和自由空间光链路中的偏振漂移是偏振编码量子密钥分发（QKD）系统误码率动态增加的一个主要因素。适用于这两种链路的动态偏振补偿方法是一项挑战。在这里，我们提出了一种普遍适用的实时偏振补偿方法，即首先使用偏振检测器检测光链路的 Muller 参数，然后通过梯度下降算法获得控制器的最优参数。仿真结果表明，与现有方法相比，该方法具有波板少、速度快、适用于各种光链路等优点。在卫星和光纤链路的等效实验中，平均极化消光比分别达到了 27.9 dB 和 32.2 dB。我们的方法的成功实现将有助于光纤和自由空间 QKD 系统的实时偏振设计，同时也有助于基于激光的偏振系统的设计。谭永健及其同事报告了一种普遍适用的量子通信实时偏振补偿方法。与目前的方法相比，该方法有几个优点，包括波板数量最少、速度更快以及更广泛地适用于各种光链路。
{"title":"Real-time polarization compensation method in quantum communication based on channel Muller parameters detection","authors":"Yongjian Tan, Jianyu Wang, Jincai Wu, Zhiping He","doi":"10.1038/s44172-024-00198-0","DOIUrl":"10.1038/s44172-024-00198-0","url":null,"abstract":"Polarization drift in fiber and free-space optical links is a major factor in the dynamic increase of bit error rate in polarization-coded quantum key distribution (QKD) systems. A dynamic polarization compensation method applicable to both links is a challenge. Here we propose a universally applicable real-time polarization compensation method, that the Muller parameters of the optical links are first detected using a polarization detector, and then the optimal parameters of the controller are obtained by gradient descent algorithm. Simulation results indicate advantages over current methods, with fewer waveplates, faster speed, and wider applicability for various optical links. In equivalent experiments of both satellite and fiber optical links, the average polarization extinction ratio of 27.9 dB and 32.2 dB are respectively achieved. The successful implementation of our method will contribute to the real-time polarization design of fiber and free-space QKD systems, while also contributing to the design of laser-based polarization systems. Yongjian Tan and colleagues report a universally applicable real-time polarization compensation method for quantum communications. The approach has several advantages over current methods, including a minimum number of waveplates, faster speed, and wider applicability for various optical links.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00198-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-22DOI: 10.1038/s44172-024-00196-2
Lea S. Kollmannsperger, Oliver Maurer, Rebecca Kose, Andre T. Zeuner, Dirk Bähre, Sarah C. L. Fischer
Metamaterials, especially lattice structures, are of great interest for many application areas such as aerospace, automotive and medicine due to their adjustable mechanical properties and their low weight. Due to their complex geometry, lattice structures are usually manufactured additively, which causes a large variance in the manufacturing-related mechanical properties. In order to establish metamaterials in industrial applications under cyclic loading, the fatigue behavior needs to be investigated to evaluate the load capacity of these structures. Here we analyze the fatigue behavior of AlSi10Mg truss structures fabricated with L-PBF using a load increase test in combination with acoustic emission measurements. The acoustic signals are evaluated in terms of time-dependent amplitude signal and frequency spectrum. Increasing load and increasing specimen damage resulted in changes of the acoustic spectrum and the amplitude of the time signal. Based on the results, a correlation of specimen properties with build platform position in the manufacturing process could be established. Acoustic emission measurement as an in situ characterization method during cyclic loading is promising for surveillance of lattice structures in safety related applications. Lea Kollmannsperger and colleagues report the fatigue behaviour of additively manufactured lattice structures under cyclic loading, relating fatigue-induced properties to process characteristics using acoustic emission. The results can help to predict damage during operation through non-destructive testing.
{"title":"Acoustic emission of lattice structures under cycling loading relates process parameters with fatigue properties","authors":"Lea S. Kollmannsperger, Oliver Maurer, Rebecca Kose, Andre T. Zeuner, Dirk Bähre, Sarah C. L. Fischer","doi":"10.1038/s44172-024-00196-2","DOIUrl":"10.1038/s44172-024-00196-2","url":null,"abstract":"Metamaterials, especially lattice structures, are of great interest for many application areas such as aerospace, automotive and medicine due to their adjustable mechanical properties and their low weight. Due to their complex geometry, lattice structures are usually manufactured additively, which causes a large variance in the manufacturing-related mechanical properties. In order to establish metamaterials in industrial applications under cyclic loading, the fatigue behavior needs to be investigated to evaluate the load capacity of these structures. Here we analyze the fatigue behavior of AlSi10Mg truss structures fabricated with L-PBF using a load increase test in combination with acoustic emission measurements. The acoustic signals are evaluated in terms of time-dependent amplitude signal and frequency spectrum. Increasing load and increasing specimen damage resulted in changes of the acoustic spectrum and the amplitude of the time signal. Based on the results, a correlation of specimen properties with build platform position in the manufacturing process could be established. Acoustic emission measurement as an in situ characterization method during cyclic loading is promising for surveillance of lattice structures in safety related applications. Lea Kollmannsperger and colleagues report the fatigue behaviour of additively manufactured lattice structures under cyclic loading, relating fatigue-induced properties to process characteristics using acoustic emission. The results can help to predict damage during operation through non-destructive testing.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00196-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1038/s44172-024-00200-9
Mo-Chou Yang, Peng Wang, Yi Wu, Guo-Ying Feng
Due to the complex physical processes found in underwater environments, such as absorption, scattering, and noise, it is challenging to obtain high-quality images using conventional camera-based imaging techniques. Ghost imaging possesses strong anti-interference capabilities and can effectively obtain images in underwater environments. Here, we propose a ghost imaging framework based on a physical model of M2-ordered laser mode patterns and apply it to Ghost Imaging. The simulation results show that the Laser Mode Speckle Ghost Imaging can reconstruct the overall trapped contour even at a low sampling rate, specifically below 0.64%. A high-quality image with a Peak Signal-to-Noise Ratio of 19 dB can be achieved using the Laser Mode Speckle Ghost Imaging when the sampling rate is 5%. Even with a relative random noise of 1.0%–5.0%, the imaging quality of Laser Mode Speckle Ghost Imaging is superior to that of Random speckle pattern Ghost Imaging, Walsh speckle pattern Ghost Imaging, and Haar speckle pattern Ghost Imaging when the sampling rate consistent. Our experimental results in a turbid water environment confirm the conclusions drawn from the simulation results. The proposed Laser Mode Speckle Ghost Imaging can be used as an imaging solution in challenging liquid environments, such as turbid liquids, inclement weather, and biological tissue fluids. Mochou Yang and colleagues describe a a ghost imaging framework based on laser mode speckle pattern which improves imaging quality at low sampling rate. The feasibility of this method is demonstrated in a turbid water environment.
由于水下环境中存在着复杂的物理过程，如吸收、散射和噪声，因此使用传统的相机成像技术获取高质量图像具有挑战性。鬼影成像具有很强的抗干扰能力，能有效获取水下环境中的图像。在此，我们提出了基于 M2 有序激光模式模式物理模型的鬼影成像框架，并将其应用于鬼影成像。仿真结果表明，激光模式斑点鬼影成像技术即使在较低的采样率下，特别是低于 0.64% 的采样率下，也能重建整个被困轮廓。当采样率为 5%时，使用激光模式斑点鬼成像技术可以获得峰值信噪比为 19 dB 的高质量图像。即使相对随机噪声为 1.0%-5.0%，当采样率一致时，激光模式斑点鬼成像的成像质量也优于随机斑点模式鬼成像、沃尔什斑点模式鬼成像和哈尔斑点模式鬼成像。我们在浑浊水环境中的实验结果证实了模拟结果得出的结论。所提出的激光模式斑点鬼成像技术可作为一种成像解决方案，用于具有挑战性的液体环境，如浑浊液体、恶劣天气和生物组织液。Mochou Yang 及其同事描述了一种基于激光模式斑点模式的鬼影成像框架，它能在低采样率下提高成像质量。他们在浑浊的水环境中演示了这种方法的可行性。
{"title":"A ghost imaging framework based on laser mode speckle pattern for underwater environments","authors":"Mo-Chou Yang, Peng Wang, Yi Wu, Guo-Ying Feng","doi":"10.1038/s44172-024-00200-9","DOIUrl":"10.1038/s44172-024-00200-9","url":null,"abstract":"Due to the complex physical processes found in underwater environments, such as absorption, scattering, and noise, it is challenging to obtain high-quality images using conventional camera-based imaging techniques. Ghost imaging possesses strong anti-interference capabilities and can effectively obtain images in underwater environments. Here, we propose a ghost imaging framework based on a physical model of M2-ordered laser mode patterns and apply it to Ghost Imaging. The simulation results show that the Laser Mode Speckle Ghost Imaging can reconstruct the overall trapped contour even at a low sampling rate, specifically below 0.64%. A high-quality image with a Peak Signal-to-Noise Ratio of 19 dB can be achieved using the Laser Mode Speckle Ghost Imaging when the sampling rate is 5%. Even with a relative random noise of 1.0%–5.0%, the imaging quality of Laser Mode Speckle Ghost Imaging is superior to that of Random speckle pattern Ghost Imaging, Walsh speckle pattern Ghost Imaging, and Haar speckle pattern Ghost Imaging when the sampling rate consistent. Our experimental results in a turbid water environment confirm the conclusions drawn from the simulation results. The proposed Laser Mode Speckle Ghost Imaging can be used as an imaging solution in challenging liquid environments, such as turbid liquids, inclement weather, and biological tissue fluids. Mochou Yang and colleagues describe a a ghost imaging framework based on laser mode speckle pattern which improves imaging quality at low sampling rate. The feasibility of this method is demonstrated in a turbid water environment.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00200-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1038/s44172-024-00199-z
Julius Metzdorf, Patrick Corhan, David Bach, Sakyo Hirose, Dirk Lellinger, Stefan Mönch, Frank Kühnemann, Olaf Schäfer-Welsen, Kilian Bartholomé
Electrocalorics (EC) is potentially more efficient than refrigeration and heat pumps based on compressors and does not need detrimental fluids. Current EC-prototypes use solid-state contact or forced convection with liquids to transfer the heat generated from the EC-material, which inhibits high cycle frequencies and thus limits power density. Here we present a heatpipe system solution, where the heat transfer is realized through condensation and evaporation of ethanol as a heat transfer fluid. Our prototype with lead scandium tantalate (PST) EC-material working at 5 Hz shows a specific cooling power of 1.5 W g−1. This is one order of magnitude more than previously reported for ceramic EC-prototypes. Overcoming the limits of slow heat transfer is essential to reach high specific cooling powers enabling a future commercial success of the technology. Julius Metzdorf and colleagues present a heatpipe system that combines solid-state electrocaloric material with condensation and evaporation of ethanol fluid. The results demonstrate an enhanced cooling power density, which is one order of magnitude higher than that of traditional ceramic electrocaloric systems.
{"title":"Electrocaloric cooling system utilizing latent heat transfer for high power density","authors":"Julius Metzdorf, Patrick Corhan, David Bach, Sakyo Hirose, Dirk Lellinger, Stefan Mönch, Frank Kühnemann, Olaf Schäfer-Welsen, Kilian Bartholomé","doi":"10.1038/s44172-024-00199-z","DOIUrl":"10.1038/s44172-024-00199-z","url":null,"abstract":"Electrocalorics (EC) is potentially more efficient than refrigeration and heat pumps based on compressors and does not need detrimental fluids. Current EC-prototypes use solid-state contact or forced convection with liquids to transfer the heat generated from the EC-material, which inhibits high cycle frequencies and thus limits power density. Here we present a heatpipe system solution, where the heat transfer is realized through condensation and evaporation of ethanol as a heat transfer fluid. Our prototype with lead scandium tantalate (PST) EC-material working at 5 Hz shows a specific cooling power of 1.5 W g−1. This is one order of magnitude more than previously reported for ceramic EC-prototypes. Overcoming the limits of slow heat transfer is essential to reach high specific cooling powers enabling a future commercial success of the technology. Julius Metzdorf and colleagues present a heatpipe system that combines solid-state electrocaloric material with condensation and evaporation of ethanol fluid. The results demonstrate an enhanced cooling power density, which is one order of magnitude higher than that of traditional ceramic electrocaloric systems.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00199-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microfluidic flowmeters are a powerful and highly accurate tool, enabling precise monitoring and measurements of flows of gases and fluids in a range of applications. Here we proposed and experimentally demonstrated a whispering gallery modes flowmeter composed of a liquid crystal-filled nested capillary. Whispering gallery modes are excited by a tapered fiber coupled perpendicularly to the nested capillary. The air flowing through the capillary cools it down, which leads to a temperature-induced change of the refractive index of the nematic liquid crystals. This change in turn leads to a spectral shift of the whispering gallery modes resonances, which can be linked to the airflow rate in the capillary. The temperature change in the liquid crystals was simulated considering the heat transfer between the liquid crystals and airflow in the capillary, which indicated that the liquid crystals temperature decreases in a nonlinear manner with the increase of the airflow rate. A flowmeter with the maximum sensitivity of 0.3423 nm·min·mL−1 in the flowrate range from 0 to 2.52 nm·min·mL−1 and a resolution of 5.72 pm was demonstrated in our experiment. The proposed sensor provides a platform for whispering gallery modes flowmeters and offers the advantages of good stability, high sensitivity, and miniature size. Wang and colleagues design a flowmeter composed of a liquid crystal-filled nested capillary which demonstrates thermal stability and high sensitivity. The device measures air flow via its cooling effect resulting in a measurable spectrum shift in whispering gallery modes.
{"title":"Microfluidic flowmeter based on a liquid crystal-filled nested capillary","authors":"Zhe Wang, Arun Kumar Mallik, Fangfang Wei, Zhuochen Wang, Anuradha Rout, Rayhan Habib Jibon, Qiang Wu, Yuliya Semenova","doi":"10.1038/s44172-024-00202-7","DOIUrl":"10.1038/s44172-024-00202-7","url":null,"abstract":"Microfluidic flowmeters are a powerful and highly accurate tool, enabling precise monitoring and measurements of flows of gases and fluids in a range of applications. Here we proposed and experimentally demonstrated a whispering gallery modes flowmeter composed of a liquid crystal-filled nested capillary. Whispering gallery modes are excited by a tapered fiber coupled perpendicularly to the nested capillary. The air flowing through the capillary cools it down, which leads to a temperature-induced change of the refractive index of the nematic liquid crystals. This change in turn leads to a spectral shift of the whispering gallery modes resonances, which can be linked to the airflow rate in the capillary. The temperature change in the liquid crystals was simulated considering the heat transfer between the liquid crystals and airflow in the capillary, which indicated that the liquid crystals temperature decreases in a nonlinear manner with the increase of the airflow rate. A flowmeter with the maximum sensitivity of 0.3423 nm·min·mL−1 in the flowrate range from 0 to 2.52 nm·min·mL−1 and a resolution of 5.72 pm was demonstrated in our experiment. The proposed sensor provides a platform for whispering gallery modes flowmeters and offers the advantages of good stability, high sensitivity, and miniature size. Wang and colleagues design a flowmeter composed of a liquid crystal-filled nested capillary which demonstrates thermal stability and high sensitivity. The device measures air flow via its cooling effect resulting in a measurable spectrum shift in whispering gallery modes.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00202-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1038/s44172-024-00201-8
Kevin P. T. Haughn, Christina Harvey, Daniel J. Inman
Uncrewed aerial vehicles are integral to a smart city framework, but the dynamic environments above and within urban settings are dangerous for autonomous flight. Wind gusts caused by the uneven landscape jeopardize safe and effective aircraft operation. Birds rapidly reject gusts by changing their wing shape, but current gust alleviation methods for aircraft still use discrete control surfaces. Additionally, modern gust alleviation controllers challenge small uncrewed aerial vehicle power constraints by relying on extensive sensing networks and computationally expensive modeling. Here we show end-to-end deep reinforcement learning forgoing state inference to efficiently alleviate gusts on a smart material camber-morphing wing. In a series of wind tunnel gust experiments at the University of Michigan, trained controllers reduced gust impact by 84% from on-board pressure signals. Notably, gust alleviation using signals from only three pressure taps was statistically indistinguishable from using six pressure tap signals. By efficiently rejecting environmental perturbations, reduced-sensor fly-by-feel controllers open the door to small uncrewed aerial vehicle missions in cities. Haughn and colleagues develop gust rejection controllers and overcome challenges of computationally expensive modeling and expansive distributed sensing networks. With only three pressure tap sensors, small fixed wing uncrewed aerial vehicles could extend into more complex urban environments.
{"title":"Deep learning reduces sensor requirements for gust rejection on a small uncrewed aerial vehicle morphing wing","authors":"Kevin P. T. Haughn, Christina Harvey, Daniel J. Inman","doi":"10.1038/s44172-024-00201-8","DOIUrl":"10.1038/s44172-024-00201-8","url":null,"abstract":"Uncrewed aerial vehicles are integral to a smart city framework, but the dynamic environments above and within urban settings are dangerous for autonomous flight. Wind gusts caused by the uneven landscape jeopardize safe and effective aircraft operation. Birds rapidly reject gusts by changing their wing shape, but current gust alleviation methods for aircraft still use discrete control surfaces. Additionally, modern gust alleviation controllers challenge small uncrewed aerial vehicle power constraints by relying on extensive sensing networks and computationally expensive modeling. Here we show end-to-end deep reinforcement learning forgoing state inference to efficiently alleviate gusts on a smart material camber-morphing wing. In a series of wind tunnel gust experiments at the University of Michigan, trained controllers reduced gust impact by 84% from on-board pressure signals. Notably, gust alleviation using signals from only three pressure taps was statistically indistinguishable from using six pressure tap signals. By efficiently rejecting environmental perturbations, reduced-sensor fly-by-feel controllers open the door to small uncrewed aerial vehicle missions in cities. Haughn and colleagues develop gust rejection controllers and overcome challenges of computationally expensive modeling and expansive distributed sensing networks. With only three pressure tap sensors, small fixed wing uncrewed aerial vehicles could extend into more complex urban environments.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00201-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1038/s44172-024-00188-2
David L. Bakker, Gustavo Castro do Amaral, Eugenio Di Iorio, Linda W. Feenstra, Ivan Ferrario, Breno Perlingeiro, Fabrizio Silvestri
Satellite identification and tracking is fundamental for decision making in space traffic management. Cooperative optical identification methods enlarge the toolbox of identification techniques which currently count on radar and passive optical observations. Here we present a cooperative method to identify satellites from the ground by means of laser techniques: the Satellite License Plate (SLP). SLP employs unique spectrally-encoded retroreflecting tags mounted on the satellite. The interrogation of the tags could be performed with laser enabled optical ground stations. The benefit of the concept is that the tag concept is fully passive, minimally invasive, and scalable from tens to hundreds of unique combinations, allowing to map a large number of satellites on a single orbit. The SLP method is here described by means of end-to-end theoretical analyses on the final performance of identification and experimental results gathered during km-range ground-to-ground free space tests. A research team from the High-Tech Industry Unit at TNO reports a method to identify satellites using retroreflecting tags with spectral signatures mounted on these satellites. The approach reduces the complexity of the observation system and does not require any power sources on board.
{"title":"Satellite License Plate: passive and compact optical spectrally-based identification method for satellites","authors":"David L. Bakker, Gustavo Castro do Amaral, Eugenio Di Iorio, Linda W. Feenstra, Ivan Ferrario, Breno Perlingeiro, Fabrizio Silvestri","doi":"10.1038/s44172-024-00188-2","DOIUrl":"10.1038/s44172-024-00188-2","url":null,"abstract":"Satellite identification and tracking is fundamental for decision making in space traffic management. Cooperative optical identification methods enlarge the toolbox of identification techniques which currently count on radar and passive optical observations. Here we present a cooperative method to identify satellites from the ground by means of laser techniques: the Satellite License Plate (SLP). SLP employs unique spectrally-encoded retroreflecting tags mounted on the satellite. The interrogation of the tags could be performed with laser enabled optical ground stations. The benefit of the concept is that the tag concept is fully passive, minimally invasive, and scalable from tens to hundreds of unique combinations, allowing to map a large number of satellites on a single orbit. The SLP method is here described by means of end-to-end theoretical analyses on the final performance of identification and experimental results gathered during km-range ground-to-ground free space tests. A research team from the High-Tech Industry Unit at TNO reports a method to identify satellites using retroreflecting tags with spectral signatures mounted on these satellites. The approach reduces the complexity of the observation system and does not require any power sources on board.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00188-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140164504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-19DOI: 10.1038/s44172-024-00194-4
Mohammad Omid Bagheri, Ali Gharamohammadi, Serene Abu-Sardanah, Omar M. Ramahi, George Shaker
Metasurfaces, promising technology exemplified by their precise manipulation of incident wave properties and exquisite control over electromagnetic field propagation, offer unparalleled benefits when integrated into radar systems, providing higher resolution and increased sensitivity. Here, we introduce a metasurface-enhanced millimeter-wave radar system for advanced near-field bio-sensing, underscoring its adaptability to the skin-device interface, and heightened diagnostic precision in non-invasive healthcare monitoring. The low-profile planar metasurface, featuring a phase-synthesized array for near-field impedance matching, integrates with radar antennas to concentrate absorbed power density within the skin medium while simultaneously improving the received power level, thereby enhancing sensor signal-to-noise ratio. Measurement verification employs a phantom with material properties resembling human skin within the radar frequency range of 58 to 63 GHz. Results demonstrate a notable increase of over 11 dB in near-field Poynting power density within the phantom model, while radar signal processing analysis indicates a commensurate improvement in signal-to-noise ratio, thus facilitating enhanced sensing in biomedical applications. Mohammad Omid Bagheri and colleagues introduce a metasurface-enhanced millimetre-wave radar system designed for near-field biosensing. Their device adapts to the properties of the skin-device interface, providing heightened diagnostic precision in wearable healthcare monitoring applications.
{"title":"Radar near-field sensing using metasurface for biomedical applications","authors":"Mohammad Omid Bagheri, Ali Gharamohammadi, Serene Abu-Sardanah, Omar M. Ramahi, George Shaker","doi":"10.1038/s44172-024-00194-4","DOIUrl":"10.1038/s44172-024-00194-4","url":null,"abstract":"Metasurfaces, promising technology exemplified by their precise manipulation of incident wave properties and exquisite control over electromagnetic field propagation, offer unparalleled benefits when integrated into radar systems, providing higher resolution and increased sensitivity. Here, we introduce a metasurface-enhanced millimeter-wave radar system for advanced near-field bio-sensing, underscoring its adaptability to the skin-device interface, and heightened diagnostic precision in non-invasive healthcare monitoring. The low-profile planar metasurface, featuring a phase-synthesized array for near-field impedance matching, integrates with radar antennas to concentrate absorbed power density within the skin medium while simultaneously improving the received power level, thereby enhancing sensor signal-to-noise ratio. Measurement verification employs a phantom with material properties resembling human skin within the radar frequency range of 58 to 63 GHz. Results demonstrate a notable increase of over 11 dB in near-field Poynting power density within the phantom model, while radar signal processing analysis indicates a commensurate improvement in signal-to-noise ratio, thus facilitating enhanced sensing in biomedical applications. Mohammad Omid Bagheri and colleagues introduce a metasurface-enhanced millimetre-wave radar system designed for near-field biosensing. Their device adapts to the properties of the skin-device interface, providing heightened diagnostic precision in wearable healthcare monitoring applications.","PeriodicalId":72644,"journal":{"name":"Communications engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44172-024-00194-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140164513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-18DOI: 10.1038/s44172-024-00184-6
A. Ben-Yehuda, O. Sefi, Y. Klein, H. Schwartz, E. Cohen, R. H. Shukrun, S. Shwartz
X-ray imaging is a prevalent technique for non-invasively visualizing the interior of the human body and other opaque samples. In most commercial X-ray modalities, an image is formed by measuring the X-rays that pass through the object of interest. However, despite the potential of scattered radiation to provide additional information about the object, it is often disregarded due to its inherent tendency to cause blurring. Consequently, conventional imaging modalities do not measure or utilize these valuable data. In contrast, we propose and experimentally demonstrate a high resolution technique for X-ray computed tomography (CT) that measures scattered radiation by exploiting computational ghost imaging (CGI). We show that the resolution of our method can exceed 500 µm, which is approximately an order of magnitude higher than the typical resolution of X-ray imaging modalities based on scattered radiation. Our research reveals a promising technique for incorporating scattered radiation data in CT scans to improve image contrast and resolution while minimizing radiation exposure for patients. The findings of our study suggest that our technique could represent a significant advancement in the fields of medical and industrial imaging, with the potential to enhance the accuracy and safety of diagnostic imaging procedures. X-ray computed tomography is a widely used technique for non-invasively visualizing the interior of the human body. A. Ben Yahuda and colleagues report a technique for incorporating scattered radiation data in Computed Tomography scans to improve image resolution and minimize radiation exposure for patients.
X 射线成像是对人体内部和其他不透明样本进行非侵入式可视化的一种流行技术。在大多数商用 X 射线模式中，图像是通过测量穿过相关物体的 X 射线形成的。然而，尽管散射辐射可能提供有关物体的额外信息，但由于其固有的导致模糊的倾向，往往被忽视。因此，传统的成像模式无法测量或利用这些宝贵的数据。与此相反，我们提出并通过实验演示了一种高分辨率的 X 射线计算机断层扫描（CT）技术，该技术通过利用计算鬼影成像（CGI）来测量散射辐射。我们的研究表明，该方法的分辨率可超过 500 微米，比基于散射辐射的 X 射线成像模式的典型分辨率高出约一个数量级。我们的研究揭示了一种将散射辐射数据纳入 CT 扫描的前景广阔的技术，它可以提高图像对比度和分辨率，同时最大限度地减少对患者的辐射照射。我们的研究结果表明，我们的技术代表了医疗和工业成像领域的一大进步，有可能提高成像诊断程序的准确性和安全性。X 射线计算机断层扫描是一种广泛应用的非侵入性人体内部成像技术。A. Ben Yahuda 及其同事报告了一种将散射辐射数据纳入计算机断层扫描的技术，以提高图像分辨率并最大限度地减少对患者的辐射照射。
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Pub Date : 2024-03-18DOI: 10.1038/s44172-024-00195-3
Yujiao Zhao, Yong Ma, Guibing Zhu, Songlin Hu, Xinping Yan
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