Photoelectrochemical(PEC)water splitting holds significant promise for sustainable energy harvesting that enables efficient conversion of solar energy into green hydrogen.Nevertheless,achievement of high performance i...Photoelectrochemical(PEC)water splitting holds significant promise for sustainable energy harvesting that enables efficient conversion of solar energy into green hydrogen.Nevertheless,achievement of high performance is often limited by charge carrier recombination,resulting in unsatisfactory saturation current densities.To address this challenge,we present a novel strategy for achieving ultrahigh current density by incorporating a bridge layer between the Si substrate and the NiOOH cocatalyst in this paper.The optimal photoanode(TCO/n-p-Si/TCO/Ni)shows a remarkably low onset potential of 0.92 V vs.a reversible hydrogen electrode and a high saturation current density of 39.6 mA·cm^(-2),which is about 92.7%of the theoretical maximum(42.7 mA·cm^(-2)).In addition,the photoanode demonstrates stable operation for 60 h.Our systematic characterizations and calculations demonstrate that the bridge layer facilitates charge transfer,enhances catalytic performance,and provides corrosion protection to the underlying substrate.Notably,the integration of this photoanode into a PEC device for overall water splitting leads to a reduction of the onset potential.These findings provide a viable pathway for fabricating highperformance industrial photoelectrodes by integrating a substrate and a cocatalyst via a transparent and conductive bridge layer.展开更多
Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be ...Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.展开更多
Silicon carbide(core third-generation wide-bandgap semiconductor)nanowires have superior characteristics and vital engineering potential in microelectric and photonic devices operating in harsh high-temperature and st...Silicon carbide(core third-generation wide-bandgap semiconductor)nanowires have superior characteristics and vital engineering potential in microelectric and photonic devices operating in harsh high-temperature and strong-irradiation environments.Herein,the dense monocrystalline forest-like 4H-and 6H-SiC nanowires(intrinsically bound as a single crystal)are fabricated using the top–down peeling method.They exhibit broadband light emissions spanning the red–green–blue spectral region.The naturally formed microcavity encapsulating the SiC nanowires yields discrete and multimodal emission lines;the luminescence lifetimes decrease to the order of picoseconds owing to improved photon density of states in the microcavity by the quantum electrodynamic Purcell effect.The measured Purcell factor of 8.35 agrees well with the theoretical value of 8.6.The low-temperature luminescence and work functions show significant dependence on the nanowire polytype.The luminescence exhibits peculiar staircase-function enhancement when the temperature is elevated to 200 K,owing to suppression of nonradiative transition channels.展开更多
The quantum dynamics of an exciton dressed by acoustic pnonons in an optically driven quantum dotsemiconductor microcavity at finite temperatures is investigated theoretically by quantum optics methods. It is shown ...The quantum dynamics of an exciton dressed by acoustic pnonons in an optically driven quantum dotsemiconductor microcavity at finite temperatures is investigated theoretically by quantum optics methods. It is shown that the temperature dependence of the vacuum Rabi splitting is 2√2g×exp[ - ∑qλq（Nq＋1/2）],where Nq=1/[exp（ωq/kBT）-1] is the phonon population, g is the single-photon Rabi frequency, and λq corresponds to exciton-phonon coupling.展开更多
The photodetachment of a hydrogen negative ion inside a circular microcavity is studied based on the semiclassical closed orbit theory. The closed orbit of the photo-detached electron in a circular microcavity is inve...The photodetachment of a hydrogen negative ion inside a circular microcavity is studied based on the semiclassical closed orbit theory. The closed orbit of the photo-detached electron in a circular microcavity is investigated and the photodetachment cross section of this system is calculated. The calculation result suggests that oscillating structure appears in the photodetachment cross section, which is caused by the interference effects of the returning electron waves with the outgoing waves traveling along the closed orbits. Besides, our study suggests that the photodetachment cross section of the negative ions depends on the laser polarization sensitively. In order to show the correspondence between the cross section and the closed orbits of the detached electron clearly, we calculate the Fourier transformation of the cross section and find that each peak corresponds to the length of one closed orbit. We hope that our results will be useful for understanding the photodetachment process of negative ions or the electron transport in a microcavity.展开更多
A new type of cavity polariton,the optical Tamm state（OTS） polariton,is proposed to be realized by sandwiching a quantum well（QW） between a gold layer and a distributed Bragg reflector（DBR）.It is shown that OTS ...A new type of cavity polariton,the optical Tamm state（OTS） polariton,is proposed to be realized by sandwiching a quantum well（QW） between a gold layer and a distributed Bragg reflector（DBR）.It is shown that OTS polaritons can be generated from the strong couplings between the QW excitons and the free OTSs.In addition,if a second gold layer is introduced into the bottom of the DBR,two independent free OTSs can interact strongly with the QW excitons to produce extra OTS polaritons.展开更多
The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the che...The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.展开更多
Stable dark soliton and dark pulse formation in normally dispersive and red-detuned microcavities are investigated by numerically solving the normalized Lugiato-Lefever equation. The soliton essence is proved by fitti...Stable dark soliton and dark pulse formation in normally dispersive and red-detuned microcavities are investigated by numerically solving the normalized Lugiato-Lefever equation. The soliton essence is proved by fitting the calculated field intensity profile with the analytical formula of a dark soliton. Meanwhile, we find that a dark soliton can be generated either from the nonlinear evolution of an optical shock wave or narrowing of a locally broad dark pulse with smoother fronts. Explicit analytical expression is obtained to describe the oscillatory fronts of the optical shock wave. Furthermore,from the calculation results, we show that for smaller frequency detunings, e.g., α 3, in addition to the dark soliton formation, a single dark pulse with an oscillatory dip can also arise and propagate stably in the microcavity under proper pump detuning and pump strength combination. The existence region together with various field intensity profiles and the corresponding spectra of single dark pulse are demonstrated.展开更多
An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapt...An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapter board technology.Four layers of high-resistance silicon substrate stack packaging are implemented based on the wafer-level gold-gold bonding process.Each layer adopts though silicon via(TSV)technology to realize signal interconnection.A core monolithic integrated microwave chip(MMIC)is embedded in the silicon cavity,and the silicon-based filter is integrated with the high-resistance silicon substrate.The interconnect line,cavity and filter of the silicon-based adapter board are designed with AutoCAD,and HFSS is adopted for 3D electromagnetic field simulation.According to the measured results,the radio frequency(RF)of the mixing multi-function chip is 40-44 GHz and its intermediate frequency(IF)can cover the Ku band with a chip size of 10 mm×11 mm×1 mm.The multiplier multi-function chip operates at 16-20 GHz.The fundamental suppression is greater than 50 dB and the second harmonic suppression is better than 40 dB with a chip size of 8 mm×8 mm×1 mm.The cascaded fully assembled mixing component achieves a spur of better than-50 dBc and a gain of better than 15 dB.展开更多
Aluminum nitride(AlN)has attracted a great amount of interest due to the fact that these group III–V semiconductors present direct band gap behavior and are compatible with current micro-electro-mechanical systems.In...Aluminum nitride(AlN)has attracted a great amount of interest due to the fact that these group III–V semiconductors present direct band gap behavior and are compatible with current micro-electro-mechanical systems.In this work,three dimensional(3D)AlN architectures including tubes and helices were constructed by rolling up AlN nanomembranes grown on a silicon-on-insulator wafer via magnetron sputtering.The properties of the AlN membrane were characterized through transmission electron microscopy and X-ray diffraction.The thickness of AlN nanomembranes could be tuned via the RIE thinning method,and thus micro-tubes with different diameters were fabricated.The intrinsic strain in AlN membranes was investigated via micro-Raman spectroscopy,which agrees well with theory prediction.Whispering gallery mode was observed in AlN tubular optical microcavity in photoluminescence spectrum.A postprocess involving atomic layer deposition and R6G immersion were employed on as-fabricated AlN tubes to promote the Q-factor.The AlN tubular micro-resonators could offer a novel design route for Si-based integrated light sources.In addition,the rolled-up technology paves a new way for AlN 3D structure fabrication,which is promising for AlN application in MEMS and photonics fields.展开更多
Manipulation of light-matter interaction is critical in modern physics, especially in the strong coupling regime, where the generated half-light, half-matter bosonic quasiparticles as polaritons are important for fund...Manipulation of light-matter interaction is critical in modern physics, especially in the strong coupling regime, where the generated half-light, half-matter bosonic quasiparticles as polaritons are important for fundamental quantum science and applications of optoelectronics and nonlinear optics. Two-dimensional transition metal dichalcogenides (TMDs) are ideal platforms to investigate the strong coupling because of their huge exciton binding energy and large absorption coefficients. Further studies on strong exciton-plasmon coupling by combining TMDs with metallic nanostructures have generated broad interests in recent years. However, because of the huge plasmon radiative damping, the observation of strong coupling is significantly limited at room temperature. Here, we demonstrate that a large Rabi splitting (~300 meV) can be achieved at ambient conditions in the strong coupling regime by embedding Ag-WS2 heterostructure in an optical microcavity. The generated quasiparticle with part-plasmon, part-exciton and part-light is analyzed with Hopfield coefficients that are calculated by using three-coupled oscillator model. The resulted plasmon-exciton polaritonic hybrid states can efficiently enlarge the obtained Rabi splitting, which paves the way for the practical applications of polaritonic devices based on ultrathin materials.展开更多
The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which ...The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.展开更多
A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit ...A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.展开更多
The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of sil...The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of silicon- hydrogen bonds on the surface migration movement of silicon atoms and the waveguide surface topography are revealed. The micro-migration from an upper state to a lower state of silicon atoms is driven by silicon- hydrogen bonding, which is the key to ameliorate the rough surface morphology of the silicon-based waveguide. The process of hydrogen annealing is experimentally validated based on the simulated parameters. The surface roughness declines from 1.523nm to 0.461 nm.展开更多
The sensitivity to fault reflection is very important for larger dynamic range in fiber fault detection technique.Using time delay signature(TDS)of chaotic laser formed by optical feedback can solve the sensitivity li...The sensitivity to fault reflection is very important for larger dynamic range in fiber fault detection technique.Using time delay signature(TDS)of chaotic laser formed by optical feedback can solve the sensitivity limitation of photodetector in fiber fault detection.The TDS corresponds to the feedback position and the fault reflection can be detected by the laser diode.The sensitivity to feedback level of circular-side hexagonal resonator(CSHR)microcavity laser is numerically simulated and the feedback level boundaries of each output dynamic state are demonstrated.The peak level of TDS is utilized to analyze the sensitivity.The demonstration is presented in two aspects:the minimum feedback level when the TDS emerges and the variation degree of TDS level on feedback level changing.The results show that the CSHR microcavity laser can respond to the feedback level of 0.07%,corresponding to-63-dB feedback strength.Compared to conventional distributed feedback laser,the sensitivity improves almost 20 dB due to the shorter internal cavity length of CSHR microcavity laser.Moreover,1%feedback level changing will induce 1.001 variation on TDS level,and this variation degree can be influenced by other critical internal parameters(active region side length,damping rate,and linewidth enhancement factor).展开更多
The behaviors of a neutrally buoyant ellipsoidal particle in vortical flow confined by a microcavity are numerically studied using the Lattice-Boltzmann method.For specific initial position,an isolated ellipsoid may d...The behaviors of a neutrally buoyant ellipsoidal particle in vortical flow confined by a microcavity are numerically studied using the Lattice-Boltzmann method.For specific initial position,an isolated ellipsoid may develop a stable limit cycle orbit inside microcavity due to the interaction between particle and the carrier flow.It is observed that ellipsoidal particles of different shapes exhibit two different stable rotational modes depending on the initial orientation and lateral position.A prolate spheroid tends to enter a tumbling mode whereas an oblate spheroid is apt to achieve a rolling mode.The evolution of rotational velocities along the stable orbit is also analyzed for particles of different shapes.展开更多
We demonstrate the curvature of coupled twin circular-side-octagon microcavity(TCOM)lasers as the degree of freedom to realize manipulation of mode quality(Q)factor and lasing characteristics.Numerical simulation resu...We demonstrate the curvature of coupled twin circular-side-octagon microcavity(TCOM)lasers as the degree of freedom to realize manipulation of mode quality(Q)factor and lasing characteristics.Numerical simulation results indicate that mode Q factors varying from 10^(4)to 10^(8),wavelength intervals of different transverse modes,and mode numbers for four-bounce modes can be manipulated for five different deformations.Global mode distributes throughout coupled microcavity with mode Q factor around the order of 10^(4)or 10^(5).Four-bounce modes lase with injection currents applied single microcavity.By pumping both microcavities simultaneously,single-mode lasing for global modes with side mode suppression ratios(SMSRs)of 30,32,32,31,and 36 dB is achieved at the deformation of 0,0.5,1,1.5,and 2 with four-bounce modes suppressed,respectively.Moreover,the linewidths less than 11 MHz for the single mode are obtained with the deformation of 2.The results show that the lasing modes can be efficiently manipulated considering variable curvature for TCOM lasers,which can promote practical applications of microcavity lasers.展开更多
Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utiliz...Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.展开更多
We design a channel-drop filter(CDF)with a linear gradient microcavity in a two-dimensional(2D)photonic crystal(PC).The model of three-port CDF with reflector is used to achieve high quality factor(Q-factor)and 100%ch...We design a channel-drop filter(CDF)with a linear gradient microcavity in a two-dimensional(2D)photonic crystal(PC).The model of three-port CDF with reflector is used to achieve high quality factor(Q-factor)and 100%channel-drop efficiency.The research indicates that adjusting the distance between reference plane and reflector can simultaneously influence the Q-factor due to coupling to a bus waveguide and the phase retardation occurring in the round trip between a microcavity and a reflector.The calculation results of 2D finite-difference time-domain(FDTD)method show that the designed filter can achieve the drop efficiency of 96.7%and ultra-high Q-factor with an ultra-small modal volume.展开更多
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ...A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.展开更多
基金supported by Multi-Year Research Grants from the University of Macao(MYRG-GRG2023-00010-IAPME,MYRG-GRG2024-00038-IAPME,MYRG2022-00026-IAPME)the Science and Technology Development Fund(FDCT)from Macao SAR(0023/2023/AFJ,0050/2023/RIB2,006/2022/ALC,0087/2024/AFJ,0111/2022/A2).
文摘Photoelectrochemical(PEC)water splitting holds significant promise for sustainable energy harvesting that enables efficient conversion of solar energy into green hydrogen.Nevertheless,achievement of high performance is often limited by charge carrier recombination,resulting in unsatisfactory saturation current densities.To address this challenge,we present a novel strategy for achieving ultrahigh current density by incorporating a bridge layer between the Si substrate and the NiOOH cocatalyst in this paper.The optimal photoanode(TCO/n-p-Si/TCO/Ni)shows a remarkably low onset potential of 0.92 V vs.a reversible hydrogen electrode and a high saturation current density of 39.6 mA·cm^(-2),which is about 92.7%of the theoretical maximum(42.7 mA·cm^(-2)).In addition,the photoanode demonstrates stable operation for 60 h.Our systematic characterizations and calculations demonstrate that the bridge layer facilitates charge transfer,enhances catalytic performance,and provides corrosion protection to the underlying substrate.Notably,the integration of this photoanode into a PEC device for overall water splitting leads to a reduction of the onset potential.These findings provide a viable pathway for fabricating highperformance industrial photoelectrodes by integrating a substrate and a cocatalyst via a transparent and conductive bridge layer.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174285 and 12474315)support from the National Natural Science Foundation of China(Grant No.62375200)+2 种基金support from the National Natural Science Foundation of China(Grant No.12504372)the China Postdoctoral Science Foundation-Tianjin Joint Support Program(Grant No.2025T003TJ)support from the National Natural Science Foundation of China(Grant No.12404424)。
文摘Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.
基金supported by the National Natural Science Foundation of China(Grant No.12274076).
文摘Silicon carbide(core third-generation wide-bandgap semiconductor)nanowires have superior characteristics and vital engineering potential in microelectric and photonic devices operating in harsh high-temperature and strong-irradiation environments.Herein,the dense monocrystalline forest-like 4H-and 6H-SiC nanowires(intrinsically bound as a single crystal)are fabricated using the top–down peeling method.They exhibit broadband light emissions spanning the red–green–blue spectral region.The naturally formed microcavity encapsulating the SiC nanowires yields discrete and multimodal emission lines;the luminescence lifetimes decrease to the order of picoseconds owing to improved photon density of states in the microcavity by the quantum electrodynamic Purcell effect.The measured Purcell factor of 8.35 agrees well with the theoretical value of 8.6.The low-temperature luminescence and work functions show significant dependence on the nanowire polytype.The luminescence exhibits peculiar staircase-function enhancement when the temperature is elevated to 200 K,owing to suppression of nonradiative transition channels.
文摘The quantum dynamics of an exciton dressed by acoustic pnonons in an optically driven quantum dotsemiconductor microcavity at finite temperatures is investigated theoretically by quantum optics methods. It is shown that the temperature dependence of the vacuum Rabi splitting is 2√2g×exp[ - ∑qλq（Nq＋1/2）],where Nq=1/[exp（ωq/kBT）-1] is the phonon population, g is the single-photon Rabi frequency, and λq corresponds to exciton-phonon coupling.
基金the National Natural Science Foundation of China(Grant No.11074104)the Higher Educational Science and Technology Program of Shandong Province,China(Grant No.J13LJ04)the University Student's Science&Technology Innovation Fund of Ludong University,China(Grant No.12z004)
文摘The photodetachment of a hydrogen negative ion inside a circular microcavity is studied based on the semiclassical closed orbit theory. The closed orbit of the photo-detached electron in a circular microcavity is investigated and the photodetachment cross section of this system is calculated. The calculation result suggests that oscillating structure appears in the photodetachment cross section, which is caused by the interference effects of the returning electron waves with the outgoing waves traveling along the closed orbits. Besides, our study suggests that the photodetachment cross section of the negative ions depends on the laser polarization sensitively. In order to show the correspondence between the cross section and the closed orbits of the detached electron clearly, we calculate the Fourier transformation of the cross section and find that each peak corresponds to the length of one closed orbit. We hope that our results will be useful for understanding the photodetachment process of negative ions or the electron transport in a microcavity.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61106045)
文摘A new type of cavity polariton,the optical Tamm state（OTS） polariton,is proposed to be realized by sandwiching a quantum well（QW） between a gold layer and a distributed Bragg reflector（DBR）.It is shown that OTS polaritons can be generated from the strong couplings between the QW excitons and the free OTSs.In addition,if a second gold layer is introduced into the bottom of the DBR,two independent free OTSs can interact strongly with the QW excitons to produce extra OTS polaritons.
基金supported by the National Natural Science Foundation of China (21875107, U1802256, and 22209204)Leading Edge Technology of Jiangsu Province (BK20220009), the Natural Science Foundation of Jiangsu Province (BK20221140)+2 种基金the China Postdoctoral Science Foundation (2022M713364)Jiangsu Specially Appointed Professors ProgramPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFF0200702)the National Natural Science Foundation of China(Grant Nos.61690222 and 11573058)the CAS-SAFEA International Partnership Program for Creative Research Teams
文摘Stable dark soliton and dark pulse formation in normally dispersive and red-detuned microcavities are investigated by numerically solving the normalized Lugiato-Lefever equation. The soliton essence is proved by fitting the calculated field intensity profile with the analytical formula of a dark soliton. Meanwhile, we find that a dark soliton can be generated either from the nonlinear evolution of an optical shock wave or narrowing of a locally broad dark pulse with smoother fronts. Explicit analytical expression is obtained to describe the oscillatory fronts of the optical shock wave. Furthermore,from the calculation results, we show that for smaller frequency detunings, e.g., α 3, in addition to the dark soliton formation, a single dark pulse with an oscillatory dip can also arise and propagate stably in the microcavity under proper pump detuning and pump strength combination. The existence region together with various field intensity profiles and the corresponding spectra of single dark pulse are demonstrated.
文摘An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapter board technology.Four layers of high-resistance silicon substrate stack packaging are implemented based on the wafer-level gold-gold bonding process.Each layer adopts though silicon via(TSV)technology to realize signal interconnection.A core monolithic integrated microwave chip(MMIC)is embedded in the silicon cavity,and the silicon-based filter is integrated with the high-resistance silicon substrate.The interconnect line,cavity and filter of the silicon-based adapter board are designed with AutoCAD,and HFSS is adopted for 3D electromagnetic field simulation.According to the measured results,the radio frequency(RF)of the mixing multi-function chip is 40-44 GHz and its intermediate frequency(IF)can cover the Ku band with a chip size of 10 mm×11 mm×1 mm.The multiplier multi-function chip operates at 16-20 GHz.The fundamental suppression is greater than 50 dB and the second harmonic suppression is better than 40 dB with a chip size of 8 mm×8 mm×1 mm.The cascaded fully assembled mixing component achieves a spur of better than-50 dBc and a gain of better than 15 dB.
基金the National Natural Science Foundation of China(Nos.61905270,51961145108)Natural Science Foundation of Shanghai(19ZR1467100)+1 种基金Science and Technology Commission of Shanghai Municipality(17JC1401700)the Program of Shanghai Academic Research Leader(19XD1400600).
文摘Aluminum nitride(AlN)has attracted a great amount of interest due to the fact that these group III–V semiconductors present direct band gap behavior and are compatible with current micro-electro-mechanical systems.In this work,three dimensional(3D)AlN architectures including tubes and helices were constructed by rolling up AlN nanomembranes grown on a silicon-on-insulator wafer via magnetron sputtering.The properties of the AlN membrane were characterized through transmission electron microscopy and X-ray diffraction.The thickness of AlN nanomembranes could be tuned via the RIE thinning method,and thus micro-tubes with different diameters were fabricated.The intrinsic strain in AlN membranes was investigated via micro-Raman spectroscopy,which agrees well with theory prediction.Whispering gallery mode was observed in AlN tubular optical microcavity in photoluminescence spectrum.A postprocess involving atomic layer deposition and R6G immersion were employed on as-fabricated AlN tubes to promote the Q-factor.The AlN tubular micro-resonators could offer a novel design route for Si-based integrated light sources.In addition,the rolled-up technology paves a new way for AlN 3D structure fabrication,which is promising for AlN application in MEMS and photonics fields.
基金the National Key Research and Development Program of China (Grant No. 2017YFA0205700)National Basic Research Program of China (Grant No. 2015CB932403, 2017YFA0206000)+3 种基金National Natural Science Foundation of China (Grant Nos. 11674012, 61521004, 21790364, 61422501, and 11374023)Beijing Natural Science Foundation (Z180011, and L140007)Foundation for the Author of National Excellent Doctoral Dissertation of PR China (Grant No. 201420)National Program for Support of Top-notch Young Professionals (Grant No. W02070003).
文摘Manipulation of light-matter interaction is critical in modern physics, especially in the strong coupling regime, where the generated half-light, half-matter bosonic quasiparticles as polaritons are important for fundamental quantum science and applications of optoelectronics and nonlinear optics. Two-dimensional transition metal dichalcogenides (TMDs) are ideal platforms to investigate the strong coupling because of their huge exciton binding energy and large absorption coefficients. Further studies on strong exciton-plasmon coupling by combining TMDs with metallic nanostructures have generated broad interests in recent years. However, because of the huge plasmon radiative damping, the observation of strong coupling is significantly limited at room temperature. Here, we demonstrate that a large Rabi splitting (~300 meV) can be achieved at ambient conditions in the strong coupling regime by embedding Ag-WS2 heterostructure in an optical microcavity. The generated quasiparticle with part-plasmon, part-exciton and part-light is analyzed with Hopfield coefficients that are calculated by using three-coupled oscillator model. The resulted plasmon-exciton polaritonic hybrid states can efficiently enlarge the obtained Rabi splitting, which paves the way for the practical applications of polaritonic devices based on ultrathin materials.
基金Project supported in part by the National Key Research and Development Program of China(Grant No.2021YFB2206504)the National Natural Science Foundation of China(Grant No.62235017)the China Postdoctoral Science Foundation(Grant No.2021M703125).
文摘The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60536030,61036002,60776024,60877035 and 61036009)National High Technology Research and Development Program of China(Grant Nos.2007AA04Z329 and 2007AA04Z254)
文摘A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51505324,91123036,61471255 and 61474079the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20131402110013the Foundation for Young Scholars of Shanxi Province under Grant No 2014021023-3
文摘The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of silicon- hydrogen bonds on the surface migration movement of silicon atoms and the waveguide surface topography are revealed. The micro-migration from an upper state to a lower state of silicon atoms is driven by silicon- hydrogen bonding, which is the key to ameliorate the rough surface morphology of the silicon-based waveguide. The process of hydrogen annealing is experimentally validated based on the simulated parameters. The surface roughness declines from 1.523nm to 0.461 nm.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFB1803500)the National Natural Science Foundation of China(Grant Nos.61705160,61961136002,61822509,and 61875147)+1 种基金the“1331 Project”Key Innovative Research Team of Shanxi Province,Chinathe National Defense Basic Scientific Research Project(Grant No.WDYX19614260203)。
文摘The sensitivity to fault reflection is very important for larger dynamic range in fiber fault detection technique.Using time delay signature(TDS)of chaotic laser formed by optical feedback can solve the sensitivity limitation of photodetector in fiber fault detection.The TDS corresponds to the feedback position and the fault reflection can be detected by the laser diode.The sensitivity to feedback level of circular-side hexagonal resonator(CSHR)microcavity laser is numerically simulated and the feedback level boundaries of each output dynamic state are demonstrated.The peak level of TDS is utilized to analyze the sensitivity.The demonstration is presented in two aspects:the minimum feedback level when the TDS emerges and the variation degree of TDS level on feedback level changing.The results show that the CSHR microcavity laser can respond to the feedback level of 0.07%,corresponding to-63-dB feedback strength.Compared to conventional distributed feedback laser,the sensitivity improves almost 20 dB due to the shorter internal cavity length of CSHR microcavity laser.Moreover,1%feedback level changing will induce 1.001 variation on TDS level,and this variation degree can be influenced by other critical internal parameters(active region side length,damping rate,and linewidth enhancement factor).
基金by the National Natural Science Foundation of China(Grants 11988102 and 91852112)the Challenge Program(Grant JCKY2016212A501).
文摘The behaviors of a neutrally buoyant ellipsoidal particle in vortical flow confined by a microcavity are numerically studied using the Lattice-Boltzmann method.For specific initial position,an isolated ellipsoid may develop a stable limit cycle orbit inside microcavity due to the interaction between particle and the carrier flow.It is observed that ellipsoidal particles of different shapes exhibit two different stable rotational modes depending on the initial orientation and lateral position.A prolate spheroid tends to enter a tumbling mode whereas an oblate spheroid is apt to achieve a rolling mode.The evolution of rotational velocities along the stable orbit is also analyzed for particles of different shapes.
基金Project supported by the Strategic Priority Research Program,Chinese Academy of Sciences(Grant No.XDB43000000)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDJSSW-JSC002)the National Natural Science Foundation of China(Grant Nos.61874113,61875188,and 61935018).
文摘We demonstrate the curvature of coupled twin circular-side-octagon microcavity(TCOM)lasers as the degree of freedom to realize manipulation of mode quality(Q)factor and lasing characteristics.Numerical simulation results indicate that mode Q factors varying from 10^(4)to 10^(8),wavelength intervals of different transverse modes,and mode numbers for four-bounce modes can be manipulated for five different deformations.Global mode distributes throughout coupled microcavity with mode Q factor around the order of 10^(4)or 10^(5).Four-bounce modes lase with injection currents applied single microcavity.By pumping both microcavities simultaneously,single-mode lasing for global modes with side mode suppression ratios(SMSRs)of 30,32,32,31,and 36 dB is achieved at the deformation of 0,0.5,1,1.5,and 2 with four-bounce modes suppressed,respectively.Moreover,the linewidths less than 11 MHz for the single mode are obtained with the deformation of 2.The results show that the lasing modes can be efficiently manipulated considering variable curvature for TCOM lasers,which can promote practical applications of microcavity lasers.
基金supported by the National Natural Science Foundation of China (51673017)the National Natural Science Foundation of China (21404005)+1 种基金the Fundamental Research Funds for the Central Universities (XK1802-2)the Natural Science Foundation of Jiangsu Province (BK20150273)。
文摘Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.
基金supported by the Natural Science Foundation of the Higher Education Institutions of Guangxi Province in China(No.201202ZD010)
文摘We design a channel-drop filter(CDF)with a linear gradient microcavity in a two-dimensional(2D)photonic crystal(PC).The model of three-port CDF with reflector is used to achieve high quality factor(Q-factor)and 100%channel-drop efficiency.The research indicates that adjusting the distance between reference plane and reflector can simultaneously influence the Q-factor due to coupling to a bus waveguide and the phase retardation occurring in the round trip between a microcavity and a reflector.The calculation results of 2D finite-difference time-domain(FDTD)method show that the designed filter can achieve the drop efficiency of 96.7%and ultra-high Q-factor with an ultra-small modal volume.
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.
