The human visual system,dependent on retinal cells,can be regarded as a complex combination of optical system and nervous system.Artificial retinal system could mimic the sensing and processing function of human eyes....The human visual system,dependent on retinal cells,can be regarded as a complex combination of optical system and nervous system.Artificial retinal system could mimic the sensing and processing function of human eyes.Optically stimulated synaptic devices could serve as the building blocks for artificial retinas and subsequent information transmission system to brain.Herein,photonic synaptic transistors based on polycrystalline MoS_(2),which could simulate human visual perception and brain storage,are presented.Moreover,the photodetection range from visible light to near-infrared light of MoS_(2) multilayer could extend human eyes’vision limitation to near-infrared light.Additionally,the photonic synaptic transistor shows an ultrafast speed within 5μs and ultralow power consumption under optical stimuli about 40 aJ,several orders of magnitude lower than biological synapses(50 ms and 10 fJ).Furthermore,the backgate control could act as emotional modulation of the artificial brain to enhance or suppress memory function,i.e.the intensity of photoresponse.The proposed carrier trapping/detrapping as the main working mechanism is presented for the device.In addition,synaptic functionalities including short synaptic plasticity,long synaptic plasticity and paired-pulse facilitation could be successfully simulated based on the prepared device.Furthermore,the large difference between short synaptic plasticity and long synaptic plasticity reveals the better image pre-processing function of the prepared photonic synapses.The classical Pavlovian conditioning associated with the associative learning is successfully implemented as well.Therefore,the efficient and rich functionalities demonstrate the potential of the MoS_(2) synaptic device that integrates sensing-memory-preprocessing capabilities for realizing artificial neural networks with different emotions that mimic human retina and brain.展开更多
The field of chiral plasmonics has registered considerable progress with machine-learning(ML)-mediated metamaterial prototyping,drawing from the success of ML frameworks in other applications such as pattern and image...The field of chiral plasmonics has registered considerable progress with machine-learning(ML)-mediated metamaterial prototyping,drawing from the success of ML frameworks in other applications such as pattern and image recognition.Here,we present an end-to-end functional bidirectional deep-learning(DL)model for three-dimensional chiral metamaterial design and optimization.This ML model utilizes multitask joint learning features to recognize,generalize,and explore in detail the nontrivial relationship between the metamaterials’geometry and their chiroptical response,eliminating the need for auxiliary networks or equivalent approaches to stabilize the physically relevant output.Our model efficiently realizes both forward and inverse retrieval tasks with great precision,offering a promising tool for iterative computational design tasks in complex physical systems.Finally,we explore the behavior of a sample ML-optimized structure in a practical application,assisting the sensing of biomolecular enantiomers.Other potential applications of our metastructure include photodetectors,polarization-resolved imaging,and circular dichroism(CD)spectroscopy,with our ML framework being applicable to a wider range of physical problems.展开更多
Thermo-plasmonics, using plasmonic structures as heat sources, has been widely used in biomedical and microfluidic applications. However, a metasurface with single-element unit cells, considered as the sole heat sourc...Thermo-plasmonics, using plasmonic structures as heat sources, has been widely used in biomedical and microfluidic applications. However, a metasurface with single-element unit cells, considered as the sole heat source in a unit cell, functions at a fixed wavelength and has limited control over the thermo-plasmonically induced hydrodynamic effects. Plasmonic metasurfaces with metal disk heterodimer lattices can be viewed to possess two heat sources within a unit cell and are therefore designed to photo-actively control thermal distributions and fluid dynamics at the nanoscale. The locations of heat sources can be switched, and the direction of the convective flow in the central region of the unit cell can be reversed by shifting the wavelength of the excitation source without any change in the excitation direction or physical actuation of the structural elements. The temperature and velocity of a fluid are spatiotemporally controlled by the wavelength selectivity and polarization sensitivity of the plasmonic metasurface. Additionally, we investigate the effects of geometric parameters on the surface lattice resonances and their impact on the temperature and fluid velocity of the optofluidic system. Our results demonstrate excellent optical control of these plasmonic metasurface heating and thermal convection performances to design flexible platforms for microfluidics.展开更多
Circular dichroism (CD) is extensively used in various material systems for applications including biological detection,enantioselective catalysis,and chiral separation.This paper introduces a chiral absorptive metasu...Circular dichroism (CD) is extensively used in various material systems for applications including biological detection,enantioselective catalysis,and chiral separation.This paper introduces a chiral absorptive metasurface that exhibits a circular polarization-selective effect in dual bands-positive and negative CD peaks at short wavelengths and long wavelengths,respectively.Significantly,we uncover that this phenomenon extends beyond the far-field optical response,as it is also observed in the photothermal effect and the dynamics of thermally induced fluid motion.By carefully engineering the metasurface design,we achieve two distinct CD signals with high g factors (1) at the wavelengths of 877 nm and 1045 nm,respectively.The findings presented in this study advance our comprehension of CD and offer promising prospects for enhancing chiral light–matter interactions in the domains of nanophotonics and optofluidics.展开更多
基金This work was financially supported by the National Key Research and Development Program of China(2019YFB2203400)the“111 Project”(B20030)+3 种基金the UESTC Shared Research Facilities of Electromagnetic Wave and Matter Interaction(Y0301901290100201)the Fundamental Research Funds for the Central Universities(ZYGX2019Z018)the National Natural Science Foundation of China(61974014)the Innovation Group Project of Sichuan Province(20CXTD0090).
文摘The human visual system,dependent on retinal cells,can be regarded as a complex combination of optical system and nervous system.Artificial retinal system could mimic the sensing and processing function of human eyes.Optically stimulated synaptic devices could serve as the building blocks for artificial retinas and subsequent information transmission system to brain.Herein,photonic synaptic transistors based on polycrystalline MoS_(2),which could simulate human visual perception and brain storage,are presented.Moreover,the photodetection range from visible light to near-infrared light of MoS_(2) multilayer could extend human eyes’vision limitation to near-infrared light.Additionally,the photonic synaptic transistor shows an ultrafast speed within 5μs and ultralow power consumption under optical stimuli about 40 aJ,several orders of magnitude lower than biological synapses(50 ms and 10 fJ).Furthermore,the backgate control could act as emotional modulation of the artificial brain to enhance or suppress memory function,i.e.the intensity of photoresponse.The proposed carrier trapping/detrapping as the main working mechanism is presented for the device.In addition,synaptic functionalities including short synaptic plasticity,long synaptic plasticity and paired-pulse facilitation could be successfully simulated based on the prepared device.Furthermore,the large difference between short synaptic plasticity and long synaptic plasticity reveals the better image pre-processing function of the prepared photonic synapses.The classical Pavlovian conditioning associated with the associative learning is successfully implemented as well.Therefore,the efficient and rich functionalities demonstrate the potential of the MoS_(2) synaptic device that integrates sensing-memory-preprocessing capabilities for realizing artificial neural networks with different emotions that mimic human retina and brain.
基金National Key Research and Development Program of China(2019YFB2203400)China Postdoctoral Science Foundation(2017M622992,2019M663467,2019T120820)+1 种基金National Science Foundation Emerging Frontiers&Multidisciplinary Activities(1741677)UESTC Shared Research Facilities of Electromagnetic Wave and Matter Interaction(Y0301901290100201)。
文摘The field of chiral plasmonics has registered considerable progress with machine-learning(ML)-mediated metamaterial prototyping,drawing from the success of ML frameworks in other applications such as pattern and image recognition.Here,we present an end-to-end functional bidirectional deep-learning(DL)model for three-dimensional chiral metamaterial design and optimization.This ML model utilizes multitask joint learning features to recognize,generalize,and explore in detail the nontrivial relationship between the metamaterials’geometry and their chiroptical response,eliminating the need for auxiliary networks or equivalent approaches to stabilize the physically relevant output.Our model efficiently realizes both forward and inverse retrieval tasks with great precision,offering a promising tool for iterative computational design tasks in complex physical systems.Finally,we explore the behavior of a sample ML-optimized structure in a practical application,assisting the sensing of biomolecular enantiomers.Other potential applications of our metastructure include photodetectors,polarization-resolved imaging,and circular dichroism(CD)spectroscopy,with our ML framework being applicable to a wider range of physical problems.
基金111 Project(B20030)National Natural Science Foundation of China(62075034)National Key Research and Development Program of China(2019YFB2203400)。
文摘Thermo-plasmonics, using plasmonic structures as heat sources, has been widely used in biomedical and microfluidic applications. However, a metasurface with single-element unit cells, considered as the sole heat source in a unit cell, functions at a fixed wavelength and has limited control over the thermo-plasmonically induced hydrodynamic effects. Plasmonic metasurfaces with metal disk heterodimer lattices can be viewed to possess two heat sources within a unit cell and are therefore designed to photo-actively control thermal distributions and fluid dynamics at the nanoscale. The locations of heat sources can be switched, and the direction of the convective flow in the central region of the unit cell can be reversed by shifting the wavelength of the excitation source without any change in the excitation direction or physical actuation of the structural elements. The temperature and velocity of a fluid are spatiotemporally controlled by the wavelength selectivity and polarization sensitivity of the plasmonic metasurface. Additionally, we investigate the effects of geometric parameters on the surface lattice resonances and their impact on the temperature and fluid velocity of the optofluidic system. Our results demonstrate excellent optical control of these plasmonic metasurface heating and thermal convection performances to design flexible platforms for microfluidics.
基金United States-Israel Binational Science Foundation(2018050)National Natural Science Foundation of China(62005037,62075034)。
文摘Circular dichroism (CD) is extensively used in various material systems for applications including biological detection,enantioselective catalysis,and chiral separation.This paper introduces a chiral absorptive metasurface that exhibits a circular polarization-selective effect in dual bands-positive and negative CD peaks at short wavelengths and long wavelengths,respectively.Significantly,we uncover that this phenomenon extends beyond the far-field optical response,as it is also observed in the photothermal effect and the dynamics of thermally induced fluid motion.By carefully engineering the metasurface design,we achieve two distinct CD signals with high g factors (1) at the wavelengths of 877 nm and 1045 nm,respectively.The findings presented in this study advance our comprehension of CD and offer promising prospects for enhancing chiral light–matter interactions in the domains of nanophotonics and optofluidics.
