Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent pr...Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent progress of a few promising contenders for on-chip light sources in terms of operating wavelength,pump condition,power consumption,and fabrication process.Additionally,the performance of each contender is also assessed with respect to thermal stability,which is a crucial parameter to consider in complex optoelectronic integrated circuits(OEICs)and optical interconnections.Currently,III-V-based silicon(Si)lasers formed via bonding techniques demonstrate the best performance and display the best opportunity for commercial usage in the near future.However,in the long term,direct hetero-epitaxial growth of III–V materials on Si seems more promising for low-cost,high-yield fabrication.The demonstration of high-performance quantum dot(QD)lasers monolithically grown on Si strongly forecasts its feasibility and enormous potential for on-chip lasers.The superior temperature-insensitive characteristics of the QD laser promote this design in large-scale high-density OEICs.The Germanium(Ge)-on-Si laser is also competitive for large-scale monolithic integration in the future.Compared with a III-V-based Si laser,the biggest potential advantage of a Ge-on-Si laser lies in its material and processing compatibility with Si technology.Additionally,the versatility of Ge facilitates photon emission,modulation,and detection simultaneously with a simple process complexity and low cost.展开更多
Femtosecond laser direct inscription is a technique especially useful for prototyping purposes due to its distinctive advantages such as high fabrication accuracy,true 3D processing flexibility,and no need for mold or...Femtosecond laser direct inscription is a technique especially useful for prototyping purposes due to its distinctive advantages such as high fabrication accuracy,true 3D processing flexibility,and no need for mold or photomask.In this paper,we demonstrate the design and fabrication of a planar lightwave circuit(PLC)power splitter encoded with waveguide Bragg gratings(WBG)using a femtosecond laser inscription technique for passive optical network(PON)fault localization application.Both the reflected wavelengths and intervals of WBGs can be conveniently tuned.In the experiment,we succeeded in directly inscribing WBGs in 1×4 PLC splitter chips with a wavelength interval of about 4 nm and an adjustable reflectivity of up to 70% in the C-band.The proposed method is suitable for the prototyping of a PLC splitter encoded with WBG for PON fault localization applications.展开更多
Light is a powerful environmental factor influencing diverse brain functions.Clinical evidence supports the beneficial effect of light therapy on several diseases,including depression,cognitive dysfunction,chronic pai...Light is a powerful environmental factor influencing diverse brain functions.Clinical evidence supports the beneficial effect of light therapy on several diseases,including depression,cognitive dysfunction,chronic pain,and sleep disorders.However,the precise mechanisms underlying the effects of light therapy are still not well understood.In this review,we critically evaluate current clinical evidence showing the beneficial effects of light therapy on diseases.In addition,we introduce the research progress regarding the neural circuit mechanisms underlying the modulatory effects of light on brain functions,including mood,memory,pain perception,sleep,circadian rhythm,brain development,and metabolism.展开更多
Impedance spectroscopy has been increasingly employed in quantum dot light-emitting diodes(QLEDs)to investigate the charge dynamics and device physics.In this review,we introduce the mathematical basics of impedance s...Impedance spectroscopy has been increasingly employed in quantum dot light-emitting diodes(QLEDs)to investigate the charge dynamics and device physics.In this review,we introduce the mathematical basics of impedance spectroscopy that applied to QLEDs.In particular,we focus on the Nyquist plot,Mott-Schottky analysis,capacitance-frequency and capacitance-voltage characteristics,and the d C/d V measurement of the QLEDs.These impedance measurements can provide critical information on electrical parameters such as equivalent circuit models,characteristic time constants,charge injection and recombination points,and trap distribution of the QLEDs.However,this paper will also discuss the disadvantages and limitations of these measurements.Fundamentally,this review provides a deeper understanding of the device physics of QLEDs through the application of impedance spectroscopy,offering valuable insights into the analysis of performance loss and degradation mechanisms of QLEDs.展开更多
When a phototube is activated to connect a neural circuit,the output voltage becomes sensitive to external illumination because the photocurrent across the phototube can be controlled by external electromagnetic wave....When a phototube is activated to connect a neural circuit,the output voltage becomes sensitive to external illumination because the photocurrent across the phototube can be controlled by external electromagnetic wave.The channel currents from different branch circuits have different impacts on the outputs voltage of the neural circuit.In this paper,a phototube is incorporated into different branch circuits in a simple neural circuit,and then a light-controlled neuron is obtained for further nonlinear analysis.Indeed,the phototube is considered as exciting source when it is activated by external illumination,and two kinds of light-sensitive neurons are obtained when the phototube is connected to capacitor or induction coil,respectively.Electric synapse coupling is applied to detect possible synchronization between two functional neurons,and the energy consumption along the coupling channel via resistor is estimated.The analog circuits for the two kinds of lightsensitive neurons are supplied for further confirmation by using Multisim.It is found that two light-sensitive neurons and neural circuits can be synchronized by taming the coupling intensity carefully.It provides possible clues to understand the synchronization mechanism for eyes and artificial sensors which are sensitive to illumination.Finally,a section for open problems is supplied for further investigation about its collective behaviors in the network with/without synapse coupling.展开更多
基金This work was partially supported by the Major International Cooperation and Exchange Program of the National Natural Science Foundation of China under Grant 61120106012the Peking University 985 Startup Fund.
文摘Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent progress of a few promising contenders for on-chip light sources in terms of operating wavelength,pump condition,power consumption,and fabrication process.Additionally,the performance of each contender is also assessed with respect to thermal stability,which is a crucial parameter to consider in complex optoelectronic integrated circuits(OEICs)and optical interconnections.Currently,III-V-based silicon(Si)lasers formed via bonding techniques demonstrate the best performance and display the best opportunity for commercial usage in the near future.However,in the long term,direct hetero-epitaxial growth of III–V materials on Si seems more promising for low-cost,high-yield fabrication.The demonstration of high-performance quantum dot(QD)lasers monolithically grown on Si strongly forecasts its feasibility and enormous potential for on-chip lasers.The superior temperature-insensitive characteristics of the QD laser promote this design in large-scale high-density OEICs.The Germanium(Ge)-on-Si laser is also competitive for large-scale monolithic integration in the future.Compared with a III-V-based Si laser,the biggest potential advantage of a Ge-on-Si laser lies in its material and processing compatibility with Si technology.Additionally,the versatility of Ge facilitates photon emission,modulation,and detection simultaneously with a simple process complexity and low cost.
基金supported by the ZTE Industry-University-Institute Fund Project under Grant No.IA20221202011。
文摘Femtosecond laser direct inscription is a technique especially useful for prototyping purposes due to its distinctive advantages such as high fabrication accuracy,true 3D processing flexibility,and no need for mold or photomask.In this paper,we demonstrate the design and fabrication of a planar lightwave circuit(PLC)power splitter encoded with waveguide Bragg gratings(WBG)using a femtosecond laser inscription technique for passive optical network(PON)fault localization application.Both the reflected wavelengths and intervals of WBGs can be conveniently tuned.In the experiment,we succeeded in directly inscribing WBGs in 1×4 PLC splitter chips with a wavelength interval of about 4 nm and an adjustable reflectivity of up to 70% in the C-band.The proposed method is suitable for the prototyping of a PLC splitter encoded with WBG for PON fault localization applications.
基金supported by grants from the National Natural Science Foundation of China(32171010 and 32100820)STI2030-Major Projects(2021ZD0203100)the Guangdong Basic and Applied Basic Research Foundation(2023B1515040010).
文摘Light is a powerful environmental factor influencing diverse brain functions.Clinical evidence supports the beneficial effect of light therapy on several diseases,including depression,cognitive dysfunction,chronic pain,and sleep disorders.However,the precise mechanisms underlying the effects of light therapy are still not well understood.In this review,we critically evaluate current clinical evidence showing the beneficial effects of light therapy on diseases.In addition,we introduce the research progress regarding the neural circuit mechanisms underlying the modulatory effects of light on brain functions,including mood,memory,pain perception,sleep,circadian rhythm,brain development,and metabolism.
基金supported by National Key Research and Development Program of China(Nos.2021YFB3602703,2022YFB3606504,and 2022YFB3602903)Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting(No.ZDSYS201707281632549)Shenzhen Science and Technology Program(No.JCYJ20220818100411025)。
文摘Impedance spectroscopy has been increasingly employed in quantum dot light-emitting diodes(QLEDs)to investigate the charge dynamics and device physics.In this review,we introduce the mathematical basics of impedance spectroscopy that applied to QLEDs.In particular,we focus on the Nyquist plot,Mott-Schottky analysis,capacitance-frequency and capacitance-voltage characteristics,and the d C/d V measurement of the QLEDs.These impedance measurements can provide critical information on electrical parameters such as equivalent circuit models,characteristic time constants,charge injection and recombination points,and trap distribution of the QLEDs.However,this paper will also discuss the disadvantages and limitations of these measurements.Fundamentally,this review provides a deeper understanding of the device physics of QLEDs through the application of impedance spectroscopy,offering valuable insights into the analysis of performance loss and degradation mechanisms of QLEDs.
基金supported by the STI2030-Major Projects(2021ZD0203100)the National Natural Science Foundation of China(31922030,32171010,31771170,31900720,and 32171009)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040010,2021B1515020035,2019A1515011598,and 2023A1515010478)the Science and Technology Program of Guangdong(2018B030334001)the Science and Technology Program of Guangzhou(202007030012)the Programme of Introducing Talents of Discipline to Universities(B14036).
基金Project supported by the National Natural Science Foundation of China(Grant No.12062009)。
文摘When a phototube is activated to connect a neural circuit,the output voltage becomes sensitive to external illumination because the photocurrent across the phototube can be controlled by external electromagnetic wave.The channel currents from different branch circuits have different impacts on the outputs voltage of the neural circuit.In this paper,a phototube is incorporated into different branch circuits in a simple neural circuit,and then a light-controlled neuron is obtained for further nonlinear analysis.Indeed,the phototube is considered as exciting source when it is activated by external illumination,and two kinds of light-sensitive neurons are obtained when the phototube is connected to capacitor or induction coil,respectively.Electric synapse coupling is applied to detect possible synchronization between two functional neurons,and the energy consumption along the coupling channel via resistor is estimated.The analog circuits for the two kinds of lightsensitive neurons are supplied for further confirmation by using Multisim.It is found that two light-sensitive neurons and neural circuits can be synchronized by taming the coupling intensity carefully.It provides possible clues to understand the synchronization mechanism for eyes and artificial sensors which are sensitive to illumination.Finally,a section for open problems is supplied for further investigation about its collective behaviors in the network with/without synapse coupling.
