Skin is the largest organ of the human body and can perceive and respond to complex environmental stimulations.Recently,the development of electronic skin(E-skin)for the mimicry of the human sensory system has drawn g...Skin is the largest organ of the human body and can perceive and respond to complex environmental stimulations.Recently,the development of electronic skin(E-skin)for the mimicry of the human sensory system has drawn great attention due to its potential applications in wearable human health monitoring and care systems,advanced robotics,artificial intelligence,and human-machine interfaces.Tactile sense is one of the most important senses of human skin that has attracted special attention.The ability to obtain unique functions using diverse assembly processible methods has rapidly advanced the use of graphene,the most celebrated two-dimensional material,in electronic tactile sensing devices.With a special emphasis on the works achieved since 2016,this review begins with the assembly and modification of graphene materials and then critically and comprehensively summarizes the most advanced material assembly methods,device construction technologies and signal characterization approaches in pressure and strain detection based on graphene and its derivative materials.This review emphasizes on:(1)the underlying working principles of these types of sensors and the unique roles and advantages of graphene materials;(2)state-of-the-art protocols recently developed for high-performance tactile sensing,including representative examples;and(3)perspectives and current challenges for graphene-based tactile sensors in E-skin applications.A summary of these cutting-edge developments intends to provide readers with a deep understanding of the future design of high-quality tactile sensing devices and paves a path for their future commercial applications in the field of E-skin.展开更多
High electro-optical conversion efficiency is one of the most distinctive features of semiconductor lasers as compared to other types of lasers.Its further increase remains a significant objective.Further enhancing th...High electro-optical conversion efficiency is one of the most distinctive features of semiconductor lasers as compared to other types of lasers.Its further increase remains a significant objective.Further enhancing the efficiency of edgeemitting lasers(EEL),which represent the highest efficiency among semiconductor lasers at present,is challenging.The efficiency of vertical cavity surface emitting lasers(VCSELs)has always been relatively low compared to EEL.This paper,combining modeling with experiments,demonstrates the potential of multi-junction cascaded VCSELs to achieve high efficiency beyond that of EELs,our simulations show,that a 20-junction VCSEL can achieve an efficiency of more than 88%at room temperature.We fabricated VCSEL devices with different numbers of junctions and compared their energy efficiency.15-junction VCSELs achieved a maximum efficiency of 74%at room temperature under nanosecond driving current,the corresponding differential quantum efficiency exceeds 1100%,being the largest electro-optical conversion efficiency and differential quantum efficiency reported until now for VCSELs.展开更多
A coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array s...A coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array supermodes can entail incoherence and spectral broadening, leading to a spatiotemporally unstable and multimode emission pattern and thus poor beam quality. Here, by harnessing notions from supersymmetric(SUSY)quantum mechanics, we report that the strategic coupling between a class III-V semiconductor microring laser array with its dissipative superpartner can be used to limit the number of supermodes available for laser actions to one. We introduce a novel approach based on second-order SUSY transformation in order to drastically simplify the superpartner array engineering. Compared to a conventional laser array, which has a multimode spectrum, a SUSY laser array is observed to be capable of operating in a single(transverse) supermode. Enhancement of the peak output intensity of the SUSY laser array has been demonstrated with high efficiency and lower lasing threshold, compared with a single laser and a conventional laser array. Our experimental findings pave the way towards broad-area and high-power light generation in a scalable and stable fashion.展开更多
基金supported by the National Key Research and Development Program of China(2017YFB0405400)National Natural Science Foundation of China(51732007)+1 种基金Major Innovation Projects in Shandong Province(2018YFJH0503)Natural Science Foundation of Shandong Province(ZR2018BEM010).
文摘Skin is the largest organ of the human body and can perceive and respond to complex environmental stimulations.Recently,the development of electronic skin(E-skin)for the mimicry of the human sensory system has drawn great attention due to its potential applications in wearable human health monitoring and care systems,advanced robotics,artificial intelligence,and human-machine interfaces.Tactile sense is one of the most important senses of human skin that has attracted special attention.The ability to obtain unique functions using diverse assembly processible methods has rapidly advanced the use of graphene,the most celebrated two-dimensional material,in electronic tactile sensing devices.With a special emphasis on the works achieved since 2016,this review begins with the assembly and modification of graphene materials and then critically and comprehensively summarizes the most advanced material assembly methods,device construction technologies and signal characterization approaches in pressure and strain detection based on graphene and its derivative materials.This review emphasizes on:(1)the underlying working principles of these types of sensors and the unique roles and advantages of graphene materials;(2)state-of-the-art protocols recently developed for high-performance tactile sensing,including representative examples;and(3)perspectives and current challenges for graphene-based tactile sensors in E-skin applications.A summary of these cutting-edge developments intends to provide readers with a deep understanding of the future design of high-quality tactile sensing devices and paves a path for their future commercial applications in the field of E-skin.
基金supported by China Scholarship Council(CSC)No.202106240176.
文摘High electro-optical conversion efficiency is one of the most distinctive features of semiconductor lasers as compared to other types of lasers.Its further increase remains a significant objective.Further enhancing the efficiency of edgeemitting lasers(EEL),which represent the highest efficiency among semiconductor lasers at present,is challenging.The efficiency of vertical cavity surface emitting lasers(VCSELs)has always been relatively low compared to EEL.This paper,combining modeling with experiments,demonstrates the potential of multi-junction cascaded VCSELs to achieve high efficiency beyond that of EELs,our simulations show,that a 20-junction VCSEL can achieve an efficiency of more than 88%at room temperature.We fabricated VCSEL devices with different numbers of junctions and compared their energy efficiency.15-junction VCSELs achieved a maximum efficiency of 74%at room temperature under nanosecond driving current,the corresponding differential quantum efficiency exceeds 1100%,being the largest electro-optical conversion efficiency and differential quantum efficiency reported until now for VCSELs.
基金Army Research Office(ARO)(W911NF-17-1-0400)National Science Foundation(NSF)(CBET-1706050,CMMI-1635026,IIP-1718177)
文摘A coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array supermodes can entail incoherence and spectral broadening, leading to a spatiotemporally unstable and multimode emission pattern and thus poor beam quality. Here, by harnessing notions from supersymmetric(SUSY)quantum mechanics, we report that the strategic coupling between a class III-V semiconductor microring laser array with its dissipative superpartner can be used to limit the number of supermodes available for laser actions to one. We introduce a novel approach based on second-order SUSY transformation in order to drastically simplify the superpartner array engineering. Compared to a conventional laser array, which has a multimode spectrum, a SUSY laser array is observed to be capable of operating in a single(transverse) supermode. Enhancement of the peak output intensity of the SUSY laser array has been demonstrated with high efficiency and lower lasing threshold, compared with a single laser and a conventional laser array. Our experimental findings pave the way towards broad-area and high-power light generation in a scalable and stable fashion.
