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High performance photonic microwave filters based on a 50GHz FSR optical soliton crystal Kerr micro-comb 基于50GHz FSR光学孤子晶体Kerr微梳的高性能光子微波滤波器
Pub Date : 2021-08-30 DOI: 10.21203/RS.3.RS-855578/V1
D. Moss
We demonstrate a photonic radio frequency (RF) transversal filter based on an integrated optical micro-comb source featuring a record low free spectral range of 49 GHz yielding 80 micro-comb lines across the C-band. This record-high number of taps, or wavelengths for the transversal filter results in significantly increased performance including a QRF factor more than four times higher than previous results. Further, by employing both positive and negative taps, an improved out-of-band rejection of up to 48.9 dB is demonstrated using Gaussian apodization, together with a tunable centre frequency covering the RF spectra range, with a widely tunable 3-dB bandwidth and versatile dynamically adjustable filter shapes. Our experimental results match well with theory, showing that our transversal filter is a competitive solution to implement advanced adaptive RF filters with broad operational bandwidths, high frequency selectivity, high reconfigurability, and potentially reduced cost and footprint. This approach is promising for applications in modern radar and communications systems.
我们展示了一种基于集成光学微梳源的光子射频(RF)横向滤波器,该滤波器具有创纪录的49 GHz低自由频谱范围,在c波段产生80条微梳线。这种创纪录的抽头数量或横向滤波器的波长导致性能显着提高,包括QRF因子比以前的结果高出四倍以上。此外,通过采用正抽头和负抽头,改进的带外抑制高达48.9 dB,使用高斯离形,以及覆盖RF频谱范围的可调谐中心频率,具有广泛可调的3db带宽和多种动态可调滤波器形状。我们的实验结果与理论吻合良好,表明我们的横向滤波器是实现先进自适应RF滤波器的有竞争力的解决方案,具有宽操作带宽,高频率选择性,高可重构性,并可能降低成本和占地面积。这种方法在现代雷达和通信系统中有很好的应用前景。
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引用次数: 8
Ultra-high bandwidth fiber-optic data transmission with a single chip source 采用单芯片源进行超高带宽光纤数据传输
Pub Date : 2021-04-27 DOI: 10.1117/12.2584014
D. Moss
We report world record high data transmission over standard optical fiber from a single optical source. We achieve a line rate of 44.2 Terabits per second (Tb/s) employing only the C-band at 1550nm, resulting in a spectral efficiency of 10.4 bits/s/Hz. We use a new and powerful class of micro-comb called soliton crystals that exhibit robust operation and stable generation as well as a high intrinsic efficiency that, together with an extremely low spacing of 48.9 GHz enables a very high coherent data modulation format of 64 QAM. We achieve error free transmission across 75 km of standard optical fiber in the lab and over a field trial with a metropolitan optical fiber network. This work demonstrates the ability of optical micro-combs to exceed other approaches in performance for the most demanding practical optical communications applications.
我们报告了世界纪录的高数据传输标准光纤从一个单一的光源。我们实现了44.2太比特每秒(Tb/s)的线路速率,仅使用c波段在1550nm,从而产生10.4比特/秒/赫兹的频谱效率。我们使用了一种新型的强大的微梳,称为孤子晶体,它具有强大的运行能力和稳定的产生能力,以及高固有效率,加上极低的48.9 GHz间距,可以实现64 QAM的高相干数据调制格式。我们在实验室实现了75公里标准光纤的无误差传输,并通过城域光纤网络进行了现场试验。这项工作证明了光学微梳在性能上超越其他方法的能力,适用于最苛刻的实际光通信应用。
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引用次数: 34
High order pulse-echo (HOPE) ultrasound 高阶脉冲回波(HOPE)超声
Pub Date : 2021-04-23 DOI: 10.21203/RS.3.RS-414115/V1
Urs A. T. Hofmann, Sergio P'erez-L'opez, H. Estrada, D. Razansky
The authors have requested that this preprint be removed from Research Square.
作者已经要求从研究广场上删除这个预印本。
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引用次数: 0
Data-driven modelling of scalable spinodoid structures for energy absorption 可伸缩棘突结构的能量吸收数据驱动建模
Pub Date : 2021-03-30 DOI: 10.17028/RD.LBORO.14588484.V1
H. Kansara, G. Koh, M. Varghese, John Z. X. Luk, E. Gómez, Siddhant Kumar, Han Zhang, Emilio Mart'inez-Paneda, Wei Tan
The project aims to explore a novel way to design and produce cellular materials with good energyabsorption and recoverability properties. Spinodoid structures offer an alternative to engineeringstructures such as honeycombs and foam with scalability ensuring microscale benefits are reapedon a larger scale. Various materials and topologies have been utilised for numerical modelingand prototyping through additive manufacturing. Each design was evaluated using finite elementmodelling. Initial results from numerical models show anisotropic structures achieving high energyabsorption efficiency. Through data-driven optimisation, results show a peak energy absorptionvalue of 5.34 MJ/m3for anisotropic columnar structure. A physics-informed biased grid-searchoptimisation is faster due to parameters being explored in parallel. To validate the numericalmodel, compressive tests on various prototypes were conducted.
该项目旨在探索一种设计和生产具有良好吸能性和可恢复性的细胞材料的新方法。spininodoid结构为蜂窝和泡沫等工程结构提供了一种替代方案,具有可扩展性,可确保在更大范围内实现微观效益。通过增材制造,各种材料和拓扑结构已被用于数值建模和原型设计。每个设计都使用有限元建模进行评估。数值模型的初步结果表明,各向异性结构具有较高的能量吸收效率。通过数据驱动优化,各向异性柱状结构的峰值能量吸收值为5.34 MJ/m3。由于并行探索参数,物理知情的有偏差网格搜索优化速度更快。为了验证数值模型,对各种原型进行了压缩试验。
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引用次数: 1
Radioplasmonics: design of plasmonic milli-particles in air and absorbing media for antenna communication and human-body in-vivo applications. 放射等离子体:设计空气和吸收介质中的等离子体毫粒子,用于天线通信和人体体内应用。
Pub Date : 2021-02-05 DOI: 10.21203/RS.3.RS-188025/V1
R. M. Abraham-Ekeroth
Surface plasmons with MHz-GHz energies are predicted by using milliparticles made of metamaterials that behave like metals in the radiofrequency range. In this work, the so-called Radioplasmonics is exploited to design scatterers embedded in different realistic media with tunable absorption or scattering properties. High-quality scattering/absorption based on plasmon excitation is demonstrated through a few simple examples, useful to build antennas with better performance than conventional ones. Systems embedded in absorbing media as saline solutions or biological tissues are also considered to improve biomedical applications and contribute with real-time, in-vivo monitoring tools in body tissues. In this regard, any possible implementation is criticized by calculating the radiofrequency heating with full thermal simulations. As proof of the versatility offered by radioplasmonic systems, plasmon “hybridization” is used to enhance near-fields to unprecedented values or to tune resonances as in optical spectra, minimizing the heating effects. Finally, a monitorable drug-delivery in human tissue is illustrated with a hypothetical example.This study has remarkable consequences on the conception of plasmonics at macroscales. The recently-developed concept of “spoof” plasmons achieved by complicated structures is simplified in Radioplasmonics since bulk materials with elemental geometries are considered.
表面等离子体具有MHz-GHz的能量是通过使用由在射频范围内表现得像金属的超材料制成的毫粒子来预测的。在这项工作中,所谓的放射等离子体被用来设计嵌入不同现实介质中的具有可调谐吸收或散射特性的散射体。通过几个简单的例子证明了基于等离子激元激发的高质量散射/吸收,有助于构建比传统天线性能更好的天线。在生理盐水溶液或生物组织等吸收介质中嵌入的系统也被认为可以改善生物医学应用,并有助于身体组织中的实时体内监测工具。在这方面,任何可能的实现都是通过计算全热模拟的射频加热来批评的。作为放射性等离子体系统提供的多功能性的证明,等离子体“杂交”用于将近场增强到前所未有的值或调谐光学光谱中的共振,从而最大限度地减少加热效应。最后,通过一个假设的例子说明了人体组织中可监测的药物递送。这项研究对宏观尺度等离子体的概念具有重要意义。由于考虑了具有元素几何形状的块状材料,最近发展的由复杂结构实现的“欺骗”等离子体激元的概念在放射等离子体学中得到了简化。
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引用次数: 0
X-ray photons produced from a plasma-cathode electron beam for radiation biology applications 等离子体阴极电子束产生的x射线光子在辐射生物学中的应用
Pub Date : 2021-01-30 DOI: 10.1063/5.0036284
F. Gobet, P. Barberet, L. Courtois, G. Devès, J. Gardelle, S. Leblanc, L. Plawinski, H. Seznec
A compact low-energy and high-intensity X-ray source for radiation biology applications is presented. A laser-induced plasma moves inside a 30 kV diode and produces a beam of 10$^{14}$ electrons at the anode location. An aluminum foil converts a part of the energy of these electrons into X-ray photons which are characterized using filtered imaging plates. The dose that would be deposited by these X-ray photons in C. elegans larvae is calculated from Geant4 simulations. It can be set to a value ranging between 10 $mu$Gy and 10 mGy per laser shot by simply changing the aluminum foil thickness and the diode voltage. Therefore, this versatile and compact X-ray source opens a new path to explore the radiation effects induced by dose rates varying over several orders of magnitude.
介绍了一种用于辐射生物学应用的小型低能量高强度x射线源。激光诱导等离子体在30kv二极管内运动,并在阳极位置产生10$^{14}$的电子束。铝箔将这些电子的一部分能量转换成x射线光子,这些光子使用过滤成像板进行表征。这些x射线光子沉积在秀丽隐杆线虫幼虫体内的剂量是通过Geant4模拟计算出来的。它可以通过简单地改变铝箔厚度和二极管电压来设置为10 $mu$Gy和10 mGy之间的值。因此,这种多功能和紧凑的x射线源为探索由几个数量级变化的剂量率引起的辐射效应开辟了新的途径。
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引用次数: 1
Soliton crystal Kerr microcombs for high-speed, scalable optical neural networks at 10 GigaOPs/s 用于高速、可扩展光学神经网络的孤子晶体Kerr微梳
Pub Date : 2021-01-29 DOI: 10.23919/MWP48676.2020.9314409
Xingyuan Xu, M. Tan, D. Moss
Optical artificial neural networks (ONNs) have significant potential for ultra-high computing speed and energy efficiency. We report a new approach to ONNs based on integrated Kerr micro-combs that is programmable, highly scalable and capable of reaching ultra-high speeds, demonstrating the building block of the ONN, a single neuron perceptron, by mapping synapses onto 49 wavelengths to achieve a single-unit throughput of 11.9 Giga-OPS at 8 bits per OP, or 95.2 Gbps. We test the perceptron on handwritten-digit recognition and cancer-cell detection, achieving over 90% and 85% accuracy, respectively. By scaling the perceptron to a deep learning network using off the shelf telecom technology we can achieve high throughput operation for matrix multiplication for real-time massive data processing.
光学人工神经网络(ONNs)在超高计算速度和能源效率方面具有巨大的潜力。我们报告了一种基于集成Kerr微梳的ONN新方法,该方法是可编程的,高度可扩展的,能够达到超高速,展示了ONN的构建模块,一个单神经元感知器,通过将突触映射到49个波长,以每OP 8位或95.2 Gbps的速度实现11.9千兆ops的单单元吞吐量。我们在手写数字识别和癌细胞检测上测试了感知器,分别达到了90%和85%以上的准确率。通过使用现成的电信技术将感知器扩展到深度学习网络,我们可以实现矩阵乘法的高吞吐量操作,用于实时大规模数据处理。
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引用次数: 0
Ultrafast spin-currents and charge conversion at 3d-5d interfaces probed by time-domain terahertz spectroscopy 时域太赫兹光谱探测3d-5d界面的超快自旋电流和电荷转换
Pub Date : 2020-12-07 DOI: 10.1063/5.0022369
T. Dang, J. Hawecker, E. Rongione, G. B. Baez Flores, D. To, J. Rojas-Sánchez, H. Nong, J. Mangeney, J. Tignon, F. Godel, S. Collin, P. Sénéor, M. Bibes, A. Fert, M. Anane, J. George, L. Vila, M. Cosset-Cheneau, D. Dolfi, R. Lebrun, P. Bortolotti, K. Belashchenko, S. Dhillon, H. Jaffrès
Spintronic structures are extensively investigated for their spin orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering for the optimization of spin transmission. Here, we advance the analysis of ultrafast spin-charge conversion phenomena at ferromagnetic-transition metal interfaces due to their inverse spin-Hall effect properties. In particular the intrinsic inverse spin Hall effect of Pt-based systems and extrinsic inverse spin-Hall effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The spin-charge conversion is probed by complementary techniques -- ultrafast THz time domain spectroscopy in the dynamic regime for THz pulse emission and ferromagnetic resonance spin-pumping measurements in the GHz regime in the steady state -- to determine the role played by the material properties, resistivities, spin transmission at metallic interfaces and spin-flip rates. These measurements show the correspondence between the THz time domain spectroscopy and ferromagnetic spin-pumping for the different set of samples in term of the spin mixing conductance. The latter quantity is a critical parameter, determining the strength of the THz emission from spintronic interfaces. This is further supported by ab-initio calculations, simulations and analysis of the spin-diffusion and spin relaxation of carriers within the multilayers in the time domain, permitting to determine the main trends and the role of spin transmission at interfaces. This work illustrates that time domain spectroscopy for spin-based THz emission is a powerful technique to probe spin-dynamics at active spintronic interfaces and to extract key material properties for spin-charge conversion.
自旋电子结构因其自旋轨道转矩特性而被广泛研究,这是磁换向功能所必需的。目前这些材料的进展依赖于界面工程来优化自旋传输。在这里,我们提出了铁磁过渡金属界面上的超快自旋-电荷转换现象的分析,这是由于它们的逆自旋-霍尔效应性质。重点研究了pt基体系的本征逆自旋霍尔效应以及NiFe/Au:(W,Ta)双层中Au:W和Au:Ta的本征逆自旋霍尔效应。利用互补技术——太赫兹脉冲发射的动态超快时域光谱和稳态GHz频段的铁磁共振自旋泵浦测量——来探测自旋电荷转换,以确定材料特性、电阻率、金属界面的自旋传输和自旋翻转速率所起的作用。这些测量结果显示了不同样品的太赫兹时域谱与铁磁自旋泵浦在自旋混合电导方面的对应关系。后一个量是决定自旋电子界面太赫兹辐射强度的关键参数。这进一步得到了时域内多层载流子自旋扩散和自旋弛豫的ab-initio计算、模拟和分析的支持,从而确定了界面处自旋传输的主要趋势和作用。这项工作表明,基于自旋的太赫兹发射时域光谱是一种强大的技术,可以探测活性自旋电子界面的自旋动力学,并提取自旋电荷转换的关键材料特性。
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引用次数: 59
Designing few-layer graphene Schottky contact solar cells: Theoretical efficiency limits and parametric optimization 设计少层石墨烯肖特基接触太阳能电池:理论效率极限和参数优化
Pub Date : 2020-12-06 DOI: 10.1063/5.0039431
Xin Zhang, Jicheng Wang, Y. Ang, Juncheng Guo
We theoretically study the efficiency limits and performance characteristics of few-layer graphene-semiconductor solar cells (FGSCs) based on a Schottky contact device structure. We model and compare the energy conversion efficiency of various configurations by explicitly considering the non-Richardson thermionic emission across few-layer graphene/semiconductor Schottky heterostructures. The calculations reveal that ABA-stacked trilayer graphene-silicon solar cell exhibits a maximal conversion efficiency exceeding 28% due to a lower reversed saturation current when compared to that of the ABC-stacking configuration. The thermal coefficients of PCE for ABA and ABC stacking FGSCs are -0.064%/K and -0.049%/K, respectively. Our work offers insights for optimal designs of graphene-based solar cells, thus paving a route towards the design of high-performance FGSC for future nanoscale energy converters.
我们从理论上研究了基于肖特基接触器件结构的少层石墨烯半导体太阳能电池(FGSCs)的效率极限和性能特征。我们通过明确考虑跨几层石墨烯/半导体肖特基异质结构的非理查德森热电子发射来模拟和比较各种构型的能量转换效率。计算结果表明,与abc堆叠结构相比,aba堆叠的三层石墨烯-硅太阳能电池由于具有较低的反向饱和电流,其最大转换效率超过28%。ABA和ABC堆叠FGSCs的PCE热系数分别为-0.064%/K和-0.049%/K。我们的工作为石墨烯基太阳能电池的优化设计提供了见解,从而为未来纳米级能量转换器的高性能FGSC设计铺平了道路。
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引用次数: 7
Hysteresis-Free Negative Capacitance Effect in Metal-Ferroelectric-Insulator-Metal Capacitors with Dielectric Leakage and Interfacial Trapped Charges 具有介电泄漏和界面俘获电荷的金属-铁电-绝缘体-金属电容器的无迟滞负电容效应
Pub Date : 2020-12-04 DOI: 10.1103/PHYSREVAPPLIED.15.034048
Chia-Sheng Hsu, Sou-Chi Chang, Dmitri E. Nikonov, I. Young, A. Naeemi
The negative capacitance (NC) stabilization of a ferroelectric (FE) material can potentially provide an alternative way to further reduce the power consumption in ultra-scaled devices and thus has been of great interest in technology and science in the past decade. In this article, we present a physical picture for a better understanding of the hysteresis-free charge boost effect observed experimentally in metal-ferroelectric-insulator-metal (MFIM) capacitors. By introducing the dielectric (DE) leakage and interfacial trapped charges, our simulations of the hysteresis loops are in a strong agreement with the experimental measurements, suggesting the existence of an interfacial oxide layer at the FE-metal interface in metal-ferroelectric-metal (MFM) capacitors. Based on the pulse switching measurements, we find that the charge enhancement and hysteresis are dominated by the FE domain viscosity and DE leakage, respectively. Our simulation results show that the underlying mechanisms for the observed hysteresis-free charge enhancement in MFIM may be physically different from the alleged NC stabilization and capacitance matching. Moreover, the link between Merz's law and the phenomenological kinetic coefficient is discussed, and the possible cause of the residual charges observed after pulse switching is explained by the trapped charge dynamics at the FE-DE interface. The physical interpretation presented in this work can provide important insights into the NC effect in MFIM capacitors and future studies of low-power logic devices.
铁电(FE)材料的负电容(NC)稳定化可以为进一步降低超大尺寸器件的功耗提供一种潜在的替代方法,因此在过去的十年中一直是技术和科学的极大兴趣。在本文中,为了更好地理解在金属-铁电-绝缘体-金属(MFIM)电容器中实验观察到的无迟滞电荷升压效应,我们给出了一个物理图。通过引入介电(DE)泄漏和界面捕获电荷,我们的滞回回路模拟与实验测量结果非常吻合,表明在金属-铁电-金属(MFM)电容器的fe -金属界面存在界面氧化层。基于脉冲开关测量,我们发现电荷增强和滞后分别受FE域粘度和DE泄漏的影响。我们的模拟结果表明,MFIM中观察到的无迟滞电荷增强的潜在机制可能与所谓的NC稳定和电容匹配在物理上不同。讨论了默兹定律与现象动力学系数之间的联系,并从FE-DE界面的俘获电荷动力学解释了脉冲开关后残余电荷产生的可能原因。在这项工作中提出的物理解释可以为MFIM电容器中的NC效应和低功耗逻辑器件的未来研究提供重要的见解。
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引用次数: 3
期刊
arXiv: Applied Physics
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