1 浙江大学极端光学技术与仪器全国重点实验室和光电科学与工程学院，浙江 杭州 310027
2 西湖大学工学院，浙江 杭州 310024
红外伪装技术是指隐藏或改变目标红外辐射特征的技术，对于提高目标的生存率具有重大意义。多波段探测技术的发展，给传统的红外伪装技术带来了严峻的挑战，使得多波段兼容红外伪装材料的研究变得十分紧迫。针对这一挑战，首先须厘清各波段的伪装要求，其次应合理利用各波段材料电磁响应的不同和结构尺寸的差异，设计分层次结构以满足不同波段的光谱要求。最后，应认识到现有研究存在的不足，向着适应更多探测波段、应用场景，制备工艺更简便、成本更低、应用性更优的方向发展。
红外伪装 兼容性伪装 热伪装 光谱调控 微纳结构 激光与光电子学进展
2024, 61(1): 0104001
Author Affiliations
Abstract
1 State Key Laboratory of Integrated Service Networks, State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology, Xidian University, Xi’an 710071, China
2 Yongjiang Laboratory, No. 1792 Cihai South Road, Ningbo 315202, China
3 The School of Communications and Information Engineering, Xi’an University of Posts and Telecommunications, Xi’an 710121, China
4 Laboratory of Solid-State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
5 School of Information Science and Technology, Nantong University, Nantong 226019, China
6 The College of Engineering and Applied Sciences, Nanjing University, Nanjing 210023, China
7 Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
8 Lightelligence Group, Hangzhou 311121, China
Neuromorphic photonic computing has emerged as a competitive computing paradigm to overcome the bottlenecks of the von-Neumann architecture. Linear weighting and nonlinear spike activation are two fundamental functions of a photonic spiking neural network (PSNN). However, they are separately implemented with different photonic materials and devices, hindering the large-scale integration of PSNN. Here, we propose, fabricate and experimentally demonstrate a photonic neuro-synaptic chip enabling the simultaneous implementation of linear weighting and nonlinear spike activation based on a distributed feedback (DFB) laser with a saturable absorber (DFB-SA). A prototypical system is experimentally constructed to demonstrate the parallel weighted function and nonlinear spike activation. Furthermore, a four-channel DFB-SA laser array is fabricated for realizing matrix convolution of a spiking convolutional neural network, achieving a recognition accuracy of 87% for the MNIST dataset. The fabricated neuro-synaptic chip offers a fundamental building block to construct the large-scale integrated PSNN chip.
neuromorphic computation photonic spiking neuron photonic integrated DFB-SA array convolutional spiking neural network Opto-Electronic Advances
2023, 6(11): 230140
Author Affiliations
Abstract
1 Ministry of Education Engineering Research Center of Smart Microsensors and Microsystems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
2 Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, 310024 Zhejiang Province, China
3 Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024 Zhejiang Province, China
The study on the nonlinear optical responses arising from plasmonic nanoantennas, known as nonlinear plasmonics, has been massively investigated in recent years. Among the most basic nonlinear optical responses, second-harmonic generation (SHG) and multiphoton photoluminescence (MPL), two-photon photoluminescence in particular, has aroused extensive interests, due to their distinct properties of being ultrasensitive to the spatial symmetry and ultrafast response time of hot electrons. In this review, we give insights into fundamental roles dominating the radiations of such nonlinear optical processes and their recent research advances. Different from other reviews on nonlinear plasmonics, which mainly focused on parametric processes, this review pays equal attentions to the incoherent process of MPL. An in-depth description on the excitation and emission processes of MPL in accordance with recent studies is fully presented. By using the high ‘symmetry rule’ of SHG and ultrafast response time of MPL, advanced applications in surface enhanced spectroscopy, ultra-sensitive photodetector, biosensor and ultrafast laser pulses are highlighted in the end.
Author Affiliations
Abstract
1 Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, China
2 Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, China
3 College of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
4 Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States
Light carries energy and momentum, laying the physical foundation of optical manipulation that has facilitated advances in myriad scientific disciplines, ranging from biochemistry and robotics to quantum physics. Utilizing the momentum of light, optical tweezers have exemplified elegant light–matter interactions in which mechanical and optical momenta can be interchanged, whose effects are the most pronounced on micro and nano objects in fluid suspensions. In solid domains, the same momentum transfer becomes futile in the face of dramatically increased adhesion force. Effective implementation of optical manipulation should thereupon switch to the “energy” channel by involving auxiliary physical fields, which also coincides with the irresistible trend of enriching actuation mechanisms beyond sole reliance on light-momentum-based optical force. From this perspective, this review covers the developments of optical manipulation in schemes of both momentum and energy transfer, and we have correspondingly selected representative techniques to present. Theoretical analyses are provided at the beginning of this review followed by experimental embodiments, with special emphasis on the contrast between mechanisms and the practical realization of optical manipulation in fluid and solid domains.
optical manipulation optical force adhesion force photothermal effects multiphysics Photonics Insights
2023, 2(2): R05
Author Affiliations
Abstract
1 Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University Hangzhou, China
2 Institute of Advanced Technology, Westlake Institute for Advanced Study, Westlake University Hangzhou, China
We design, fabricate, optically and mechanically characterize wearable ultrathin coatings on various substrates, including sapphire, glass and silicon wafer. Extremely hard ceramic materials titanium nitride (TiN), aluminium nitride (AlN), and titanium aluminium nitride (TiAlN) are employed as reflective, isolated and absorptive coating layer, respectively. Two types of coatings have been demonstrated. First, we deposit TiAlN after TiN on various substrates (TiAlN-TiN, total thicknesses <100 nm), achieving vivid and viewing-angle independent surface colors. The colors can be tuned by varying the thickness of TiAlN layer. The wear resistance of the colorful ultrathin optical coatings is verified by scratch tests. The Mohs hardness of commonly used surface coloring made of Si-/Ge-metals on substrates is <2.5, as soft as fingernail. However, the Mohs hardness of our TiAlN-TiN on substrates is evaulated to be 7-9, harder than quartz. Second, Fano-resonant optical coating (FROC), which can transmit and reflect the same color as a beam split filter is also obtained by successively coating TiAlN-TiN-AlN-TiN (four-layer film with a total thickness of 130 nm) on transparent substrates. The FROC coating is as hard as glass. Such wearable and color-tunable thin-film structural colors and filters may be attractive for many practical applications such as sunglasses.
Author Affiliations
Abstract
1 University of Chinese Academy of Sciences, Hangzhou Institute for Advanced Study, College of Physics and Optoelectronic Engineering, Hangzhou, China
2 Westlake University, School of Engineering, Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, Hangzhou, China
3 Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, China
Manipulating motion of microobjects with light is indispensable in various technologies. On solid interfaces, its realizations, however, are hampered by surface friction. To resolve this difficulty, light-induced elastic waves have been recently proposed to drive microobjects against friction. Despite its expected applicability for arbitrary optical-absorptive objects, the new principle has only been tested with microsized gold plates. Herein, we validate this principle using a new material and report directional and continuous movements of a two-dimensional topological insulator (Sb2Te3) plate on an untreated microfiber surface driven by nanosecond laser pulses. The motion performance of the Sb2Te3 plate is characterized by a scanning electron microscope. We observe that the motion velocity can be controlled by tuning the average power of laser pulses. Further, by intentionally increasing the pulse repetition rate and exploiting the low thermal conductivity of Sb2Te3, we examine the thermal effects on actuation and reveal the motion instability induced by formations of microbumps on Sb2Te3 surfaces due to the Marangoni effects. Moreover, as the formed microbumps are heated to viscoelasticity states, liquid-like motion featuring asymmetry in contact angles is observed and characterized, which expands the scope of light-induced actuation of microobjects.
optical actuation nonliquid environment topological insulator Advanced Photonics Nexus
2022, 1(2): 026005
Author Affiliations
Abstract
1 Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou Zhejiang Province, China
2 Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou Zhejiang Province, China
3 Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, 53706 WI, USA
4 AI lab, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou Zhejiang Province, China
Applying intelligence algorithms to conceive nanoscale meta-devices becomes a flourishing and extremely active scientific topic over the past few years. Inverse design of functional nanostructures is at the heart of this topic, in which artificial intelligence (AI) furnishes various optimization toolboxes to speed up prototyping of photonic layouts with enhanced performance. In this review, we offer a systemic view on recent advancements in nanophotonic components designed by intelligence algorithms, manifesting a development trend from performance optimizations towards inverse creations of novel designs. To illustrate interplays between two fields, AI and photonics, we take meta-atom spectral manipulation as a case study to introduce algorithm operational principles, and subsequently review their manifold usages among a set of popular meta-elements. As arranged from levels of individual optimized piece to practical system, we discuss algorithm-assisted nanophotonic designs to examine their mutual benefits. We further comment on a set of open questions including reasonable applications of advanced algorithms, expensive data issue, and algorithm benchmarking, etc. Overall, we envision mounting photonic-targeted methodologies to substantially push forward functional artificial meta-devices to profit both fields.
为了解决平面数据点位精度差异性及平面模型常数项解算精度较低的问题, 提出了一种基于最小二乘-加权总体最小二乘(LS-WTLS)的稳健平面拟合方法。该方法采用加权最小二乘模型与稳健估计IGGⅢ方案相结合的方式对平面模型误差项参量进行解算, 然后通过设置阈值剔除粗差数据, 利用最小二乘法对平面模型常数项进行解算, 以此进一步提高了平面模型各参量的解算精度。结果表明,新方法相对于最小二乘(LS)法、总体最小二乘(TLS)法、LS-TLS法、IGGⅢ-LS-TLS法, 其单位权中误差分别提高了53.6%,195.0%,47.5%和5.1%, 平面拟合精度分别提高了49.4%,179.3%,48.7%和46.99%, 表现出了良好的抗粗差干扰能力。该研究验证了新方法在平面拟合领域的优越性和可靠性。
测量与计量, 稳健平面拟合方法, 加权总体最小二乘, 稳 measurement and metrology robust methods of fitting plane weighted total least squares robust estimation IGGⅢ scheme
1 中国科学院上海光学精密机械研究所 中科院空间激光信息传输与探测技术重点实验室, 上海201800
2 中国科学院大学, 北京 100049
星载积分路径差分吸收(IPDA)激光雷达是全天时全球范围内探测CO2浓度的一种有效的方法, 而作为接收系统关键元件的光电探测器对激光雷达系统性能有着较大的影响。雪崩光电二极管(APD)有着较大的动态范围与高的响应度, 因此它在星载激光雷达中广泛应用。介绍了IPDA激光雷达和APD探测器的工作原理, 并根据实际工作条件, 测试了一款APD探测单元的响应度、动态范围、不同光功率下的信噪比等主要性能参数, 分析了这些性能参数对星载激光雷达CO2浓度的反演带来的影响。结果表明, 在CO2浓度为400 ppm(1 ppm=10-6), 吸收波段信号的探测器输出电压在280~980 mV范围内时, APD探测器本身的非线性和噪声造成的误差小于0.8 ppm。
误差分析 积分路径差分吸收激光雷达 APD探测器 非线性 信噪比 error analysis IPDA lidar APD detector non-linearity signal to noise ratio 红外与激光工程
2018, 47(4): 0406002
