Rhenium diselenide(ReSe2) has caused considerable concerns in the field of energy storage because the compound and its composites still suffer from low specific capacity and inferior cyclic stability.In this study,ReS...Rhenium diselenide(ReSe2) has caused considerable concerns in the field of energy storage because the compound and its composites still suffer from low specific capacity and inferior cyclic stability.In this study,ReSe2 nanoparticles encapsulated in carbon nanofibers were synthesized successfully with simple electrospinning and heat treatment.It was found that graphene modifications could affect considerably the microstructure and electrochemical properties of ReSe2–carbon nanofibers.Accordingly,the modified compound maintained a capacity of 227 mAhg-1 after 500cycles at 200 mAg-1 for Na+storage,230 mAh g-1 after 200 cycles at 200 mAg-1,212 mAh g-1 after 150 cycles at 500 mAg-1 for K+ storage,which corresponded to the capacity retention ratios of 89%,97%,and 86%,respectively.Even in Na+full cells,its capacity was maintained to 82% after 200 cycles at 1 C(117 mAg-1).The superior stability of ReSe2–carbon nanofibers benefitted from the extremely weak van der Waals interactions and large interlayer spacing of ReSe2,in association with the role of graphene-modified carbon nanofibers,in terms of the shortening of electron/ion transport paths and the improvement of structural support.This study may provide a new route for a broadened range of applications of other rhenium-based compounds.展开更多
Carbon nanofibers films are typical flexible electrode in the field of energy storage,but their application in Zinc-ion hybrid capacitors(ZIHCs)is limited by the low energy density due to the lack of active adsorption...Carbon nanofibers films are typical flexible electrode in the field of energy storage,but their application in Zinc-ion hybrid capacitors(ZIHCs)is limited by the low energy density due to the lack of active adsorption sites.In this work,an in-situ exfoliation strategy is reported to modulate the chemisorption sites of carbon nanofibers by high pyridine/pyrrole nitrogen doping and carbonyl functionalization.The experimental results and theoretical calculations indicate that the highly electronegative pyridine/pyrrole nitrogen dopants can not only greatly reduce the binding energy between carbonyl group and Z n2+by inducing charge delocalization of the carbonyl group,but also promote the adsorption of Zn2+by bonding with the carbonyl group to form N–Zn–O bond.Benefit from the multiple highly active chemisorption sites generated by the synergy between carbonyl groups and pyridine/pyrrole nitrogen atoms,the resulting carbon nanofibers film cathode displays a high energy density,an ultralong-term lifespan,and excellent capacity reservation under commercial mass loading(14.45 mg cm-2).Particularly,the cathodes can also operate stably in flexible or quasi-solid devices,indicating its application potential in flexible electronic products.This work established a universal method to solve the bottleneck problem of insufficient active adsorption sites of carbon-based ZIHCs.Imoproved should be changed into Improved.展开更多
The catalytic performance of Molybdenum disulfide(MoS_(2)) has been still far from that of Pt-based catalysts for inadequate active sites and sluggish electron transfer kinetics. Through engineering the interface betw...The catalytic performance of Molybdenum disulfide(MoS_(2)) has been still far from that of Pt-based catalysts for inadequate active sites and sluggish electron transfer kinetics. Through engineering the interface between MoS_(2)-based materials and supported substrates, hybrid Ru-doped MoS_(2) on carbonized lignin(CL) is designed and prepared as efficient catalyst for hydrogen evolution reaction(HER). The CL substrate not only facilitates the growth of MoS_(2) nanoflowers, but also promotes the electron transfer. Ru doping increases active sites greatly for HER. The hybrid catalyst achieves a low onset overpotential of 25 mV and a low Tafel slope of 46 m V dec^(-1). The favorable HER activity ascribes to the interfacial interaction between MoS_(2) and CL. Density functional theory calculations further confirm the improved HER performance with doped Ru atoms. This study presents a prototype application to design electrocatalysts with enhanced carrier mobility and high-density active sites based on interface effect.展开更多
Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carb...Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carbon materials show great potential for potassium-ion storage,poor rate performance,and unsatisfactory cycle lifespan in existing carbon-based PIBs anode,it also cannot match the dynamics and stability of the capacitor cathode.Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials.Hence,we prepare carbon nanofibers and g-C_(3)N_(4)composites with high nitrogen contents(19.78 at%);moreover,the sum of pyrrolic N and pyridinic N is up to 59.51%.It achieves high discharge capacity(391 m Ah g^(-1)at0.05 A g^(-1)),rate capacity(141 m Ah g^(-1)at 2 A g^(-1)),and long cycling performance(201 m Ah g^(-1)at 1 A g^(-1)over 3000 cycles)when as an anode for PIBs.Furthermore,it can deliver promising discharge capacity of132 m Ah g^(-1)at 0℃.Moreover,as battery anode for potassium-ion hybrid capacitors(PIHC)device with an active carbon cathode,it delivers energy/power density(62 and 2102 W kg^(-1))as well as high reversible capacity(106 m Ah g^(-1)at 1 A g^(-1)).展开更多
Carbon group element-based materials are the most widely used anode materials for Li-ion batteries(LIBs).However,their performance is limited by the low capacity(eg,graphite)or high-volume changes(eg,Si and Sn).Theref...Carbon group element-based materials are the most widely used anode materials for Li-ion batteries(LIBs).However,their performance is limited by the low capacity(eg,graphite)or high-volume changes(eg,Si and Sn).Therefore,exploring high-performance anode materials is quite appealing and promising.By first-principle calculations in this study,we found that distorted T-carbon(DTC)as a desired LIB anode shows properties of the enhanced capacity,decreased volume change,and the increased ion migration.The origin of such improved properties is attributed to the interconnected tunnels and large cavities of the carbon skeleton.The theoretical specific capacity of DTC is found to be 558 mAh/g,which is 1.5 times higher than that of commercial graphite anodes.Interestingly,the volume change of the DTC anode is only 3%at the full-lithiation state(one-fifth of that of the commercial graphite anode),which can overcome the pulverization problem in most high-capacity anode materials and attain a longer cycling lifetime.Both transition state calculations and molecular dynamics simulations demonstrate that the Li-ion migration barrier is less than 0.1 eV and the Li-ion vacancy is only 0.2 eV,enabling its promising rate performance.This study provides a new and effective strategy to improve the anode properties of LIBs.展开更多
While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remai...While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.展开更多
Semiconductor electrocatalysis with weak conductivity can accumulate extremely high carriers at semiconductor-electrolyte interface by self-gating effect,which strongly promotes electrocatalytic efficiency.The correla...Semiconductor electrocatalysis with weak conductivity can accumulate extremely high carriers at semiconductor-electrolyte interface by self-gating effect,which strongly promotes electrocatalytic efficiency.The correlation between semiconductor carrier mobility and electrocatalysis performance is still unclear.Herein atomic-thin transition metal dichalcogenides based composites have been developed for hydrogen evolution reaction(HER)performed with on-chip microdevices.Electrical and electrochemical measurement of individual flack verified the key role of high carrier mobility for enhanced HER activity.Carrier mobility regulation further demonstrated its high dependence with HER performance under self-gating.Our study provides new insight into the carrier mobility of the semiconductor in the electrocatalysis,paving the way for designing high-performance semiconductor catalysts.展开更多
More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging ...More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging material developed by photo-alignment technology,is a potential material for organizing the long-range ordered structure of azo dyes.However,little research has been done on LCP aligned azo dyes.This paper points out and solves a key problem that restricts the fabrication of high-precision arrays in guest[azo dye]-host[LCP]systems:the doping of dyes leads to disorder of the LCP during curing.After solving the problem,the relationship between the thickness of the LCP and the extinction ratio of the polarizing film was investigated,which effectively improved the extinction ratio.Alignment of azo dye molecules in the range of 2μm[0°-180°]and arrays of micropolarizers[0°,45°,90°,-45°]with 8μm×8μm pixel pitch was achieved by laser direct writing technology.The bending cycle test demonstrates the mechanical stability of the ultrathin flexible polarizer.The flexible patterned polarizer with robust chemical and mechanical stabilities provides a flexible way to capture the polarization of the light and highly integrated advanced flexible optoelectronic devices.展开更多
Ultrafast fiber lasers are in great demand for various applications, such as optical communication, spectroscopy,biomedical diagnosis, and industrial fabrication. Here, we report the highly stable femtosecond pulse ge...Ultrafast fiber lasers are in great demand for various applications, such as optical communication, spectroscopy,biomedical diagnosis, and industrial fabrication. Here, we report the highly stable femtosecond pulse generation from a MXene mode-locked fiber laser. We have prepared the high-quality Ti_3C_2 T_x nanosheets via the etching method, and characterized their ultrafast dynamics and broadband nonlinear optical responses. The obvious intensity-and wavelength-dependent nonlinear responses have been observed and investigated. In addition, a highly stable femtosecond fiber laser with signal-to-noise ratio up to 70.7 dB and central wavelength of 1567.3 nm has been delivered. The study may provide some valuable design guidelines for the development of ultrafast, broadband nonlinear optical modulators, and open new avenues toward advanced photonic devices based on MXenes.展开更多
We provide a perspective review over the recent development of short-pulsed Raman fiber lasers(RFLs),which can provide laser emissions with flexible wavelengths for a variety of applications as well as an excellent pl...We provide a perspective review over the recent development of short-pulsed Raman fiber lasers(RFLs),which can provide laser emissions with flexible wavelengths for a variety of applications as well as an excellent platform to investigate various nonlinear pulse dynamics behaviors that cannot be captured in conventional rare-earth(RE)doped counterparts.Various pulse generation techniques have been explored in RFLs.However,the output pulse performance in terms of the pulse energy,duration and stability from short-pulsed RFLs is still inferior to their RE-doped counterparts despite significant advances made over the past few decades.Therefore,more efforts are required to improve these targets.In this review,we present a detailed overview of the short-pulsed RFLs based on different mechanisms from the principle to the experiment,including the Q-switching,gainswitching,mode-locking,synchronous pumping and other innovative techniques.In addition,Raman-induced pulse dynamics in ultrafast RFLs and RE-doped mode-locked fiber lasers(MLFLs)are briefly reviewed.Finally,a perspective outlook for the future ultrafast RFLs is provided based on their potential applications in industrial and scientific research areas.展开更多
In this Letter, a photonic crystal(PC) flat lens with a scatterer-size gradient is proposed, which simultaneously achieves imaging of the point source and sub-wavelength focusing of the plane wave in the first, second...In this Letter, a photonic crystal(PC) flat lens with a scatterer-size gradient is proposed, which simultaneously achieves imaging of the point source and sub-wavelength focusing of the plane wave in the first, second, and fifth bands. The imaging of the point source breaks through the diffraction limit in the second and fifth bands. The PC flat lens with the scatterer-size gradient is expected to be used in a new multifunctional optical imaging and focusing device, which improves the application potential of a PC flat lens.展开更多
MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXen...MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXene nanosheets dispersed in deionized water in the visible to near-infrared regime,highlighting the broadband nonlinear optical(NLO)response of Ti2CTx MXene.Using ultrafast pulsed laser excitation,the nonlinear refractive index n2 and the thirdorder nonlinear susceptibility χ^(3)monolayer of Ti2CTx MXene were measured to be^10^−13 m^2/W and ~10^−10 esu,respectively.Leveraging the large optical nonlinearity of Ti2CTx MXene,an all-optical modulator in the visible regime was fabricated based on the spatial cross-phase modulation effect.This work suggests that 2D MXenes are ideal broadband NLO materials with excellent prospects in NLO applications.展开更多
Mid-infrared pulsed lasers operating around the 3 μm wavelength regime are important for a wide range of applications including sensing, spectroscopy, imaging, etc. Despite the recent advances in technology, the lack...Mid-infrared pulsed lasers operating around the 3 μm wavelength regime are important for a wide range of applications including sensing, spectroscopy, imaging, etc. Despite the recent advances in technology, the lack of a nonlinear optical modulator operating in the mid-infrared regime remains a significant challenge. Here, we report the third-order nonlinear optical response of gold nanorods(GNRs) ranging from 800 nm to the mid-infrared regime(2810 nm) enabled by their size and overlapping behavior-dependent longitudinal surface plasmon resonance. In addition, we demonstrate a wavelength-tunable Er3+-doped fluoride fiber laser modulated by GNRs, which can deliver pulsed laser output, with the pulse duration down to 533 ns, tunable wavelength ranging from 2760.2 to 2810.0 nm, and spectral 3 d B bandwidth of about 1 nm. The experimental results not only validate the GNRs’ robust mid-infrared nonlinear optical response, but also manifest their application potential in high-performance broadband optoelectronic devices.展开更多
基金supported by the National Natural Science Foundation of China(Grants51772082,51574117,and 51804106)the Research Projects of Degree and Graduate Education Teaching Reformation in Hunan Province(JG2018B031,JG2018A007)+1 种基金the Natural Science Foundation of Hunan Province(2019JJ30002,2019JJ50061)project funded by the China Postdoctoral Science Foundation(2017M610495,2018T110822)
文摘Rhenium diselenide(ReSe2) has caused considerable concerns in the field of energy storage because the compound and its composites still suffer from low specific capacity and inferior cyclic stability.In this study,ReSe2 nanoparticles encapsulated in carbon nanofibers were synthesized successfully with simple electrospinning and heat treatment.It was found that graphene modifications could affect considerably the microstructure and electrochemical properties of ReSe2–carbon nanofibers.Accordingly,the modified compound maintained a capacity of 227 mAhg-1 after 500cycles at 200 mAg-1 for Na+storage,230 mAh g-1 after 200 cycles at 200 mAg-1,212 mAh g-1 after 150 cycles at 500 mAg-1 for K+ storage,which corresponded to the capacity retention ratios of 89%,97%,and 86%,respectively.Even in Na+full cells,its capacity was maintained to 82% after 200 cycles at 1 C(117 mAg-1).The superior stability of ReSe2–carbon nanofibers benefitted from the extremely weak van der Waals interactions and large interlayer spacing of ReSe2,in association with the role of graphene-modified carbon nanofibers,in terms of the shortening of electron/ion transport paths and the improvement of structural support.This study may provide a new route for a broadened range of applications of other rhenium-based compounds.
基金funds from the National Natural Science Foundation of China(51772082,51804106,and 51574117)the Natural Science Foundation of Hunan Province(2019JJ30002,2019JJ50061 and 2020CB1007)Natural Science Foundation of Guangdong Providence(2018A030310571)。
文摘Carbon nanofibers films are typical flexible electrode in the field of energy storage,but their application in Zinc-ion hybrid capacitors(ZIHCs)is limited by the low energy density due to the lack of active adsorption sites.In this work,an in-situ exfoliation strategy is reported to modulate the chemisorption sites of carbon nanofibers by high pyridine/pyrrole nitrogen doping and carbonyl functionalization.The experimental results and theoretical calculations indicate that the highly electronegative pyridine/pyrrole nitrogen dopants can not only greatly reduce the binding energy between carbonyl group and Z n2+by inducing charge delocalization of the carbonyl group,but also promote the adsorption of Zn2+by bonding with the carbonyl group to form N–Zn–O bond.Benefit from the multiple highly active chemisorption sites generated by the synergy between carbonyl groups and pyridine/pyrrole nitrogen atoms,the resulting carbon nanofibers film cathode displays a high energy density,an ultralong-term lifespan,and excellent capacity reservation under commercial mass loading(14.45 mg cm-2).Particularly,the cathodes can also operate stably in flexible or quasi-solid devices,indicating its application potential in flexible electronic products.This work established a universal method to solve the bottleneck problem of insufficient active adsorption sites of carbon-based ZIHCs.Imoproved should be changed into Improved.
基金supported by National Natural Science Foundation of China (21705036, 21975067, 11974105, and 11634001)National Basic Research Programs of China (2016YFA0300901)+3 种基金Natural Science Foundation of Hunan Province, China (2018JJ3035)Fundamental Research Funds for the Central Universities from Hunan Universityfinancially supported by the fund of Prof. Hong from University of Macao (SRG201600092-IAPME, MYRG2018-00079-IAPME, MYRG2019-00115-IAPME)the Science and Technology Development Fund, Macao SAR (FDCT081/2017/A2, FDCT0059/2018/A2, FDCT009/2017/AMJ)
文摘The catalytic performance of Molybdenum disulfide(MoS_(2)) has been still far from that of Pt-based catalysts for inadequate active sites and sluggish electron transfer kinetics. Through engineering the interface between MoS_(2)-based materials and supported substrates, hybrid Ru-doped MoS_(2) on carbonized lignin(CL) is designed and prepared as efficient catalyst for hydrogen evolution reaction(HER). The CL substrate not only facilitates the growth of MoS_(2) nanoflowers, but also promotes the electron transfer. Ru doping increases active sites greatly for HER. The hybrid catalyst achieves a low onset overpotential of 25 mV and a low Tafel slope of 46 m V dec^(-1). The favorable HER activity ascribes to the interfacial interaction between MoS_(2) and CL. Density functional theory calculations further confirm the improved HER performance with doped Ru atoms. This study presents a prototype application to design electrocatalysts with enhanced carrier mobility and high-density active sites based on interface effect.
基金supported by the National Natural Science Foundation of China(Grants 51772082,51574117,and 51804106)the Research Projects of Degree and Graduate Education Teaching Reformation in Hunan Province(JG2018B031)+2 种基金the Natural Science Foundation of Hunan Province(2019JJ30002,2019JJ50061)the Guangdong Basic and Applied Basic Research Foundation(No.2019B151502045)the National Natural Science Foundation of China(Nos.51802361,51972351)
文摘Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carbon materials show great potential for potassium-ion storage,poor rate performance,and unsatisfactory cycle lifespan in existing carbon-based PIBs anode,it also cannot match the dynamics and stability of the capacitor cathode.Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials.Hence,we prepare carbon nanofibers and g-C_(3)N_(4)composites with high nitrogen contents(19.78 at%);moreover,the sum of pyrrolic N and pyridinic N is up to 59.51%.It achieves high discharge capacity(391 m Ah g^(-1)at0.05 A g^(-1)),rate capacity(141 m Ah g^(-1)at 2 A g^(-1)),and long cycling performance(201 m Ah g^(-1)at 1 A g^(-1)over 3000 cycles)when as an anode for PIBs.Furthermore,it can deliver promising discharge capacity of132 m Ah g^(-1)at 0℃.Moreover,as battery anode for potassium-ion hybrid capacitors(PIHC)device with an active carbon cathode,it delivers energy/power density(62 and 2102 W kg^(-1))as well as high reversible capacity(106 m Ah g^(-1)at 1 A g^(-1)).
基金This study is financially supported by the National Natural Science Foundation of China(Grant no.51972106 and 11904094)Lei Du acknowledges the scholarship under the International Postdoctoral Exchange Fellowship Program by the Office of China Postdoctoral Council(Grant no.20180072)+1 种基金the Fonds de Recherche du Québec-Nature et Technologies for Postdoctoral scholarship(V2,file number:274384)Xiaohua Yang acknowledges the scholarship from the China Scholarship Council。
文摘Carbon group element-based materials are the most widely used anode materials for Li-ion batteries(LIBs).However,their performance is limited by the low capacity(eg,graphite)or high-volume changes(eg,Si and Sn).Therefore,exploring high-performance anode materials is quite appealing and promising.By first-principle calculations in this study,we found that distorted T-carbon(DTC)as a desired LIB anode shows properties of the enhanced capacity,decreased volume change,and the increased ion migration.The origin of such improved properties is attributed to the interconnected tunnels and large cavities of the carbon skeleton.The theoretical specific capacity of DTC is found to be 558 mAh/g,which is 1.5 times higher than that of commercial graphite anodes.Interestingly,the volume change of the DTC anode is only 3%at the full-lithiation state(one-fifth of that of the commercial graphite anode),which can overcome the pulverization problem in most high-capacity anode materials and attain a longer cycling lifetime.Both transition state calculations and molecular dynamics simulations demonstrate that the Li-ion migration barrier is less than 0.1 eV and the Li-ion vacancy is only 0.2 eV,enabling its promising rate performance.This study provides a new and effective strategy to improve the anode properties of LIBs.
基金the National Natural Science Foundation of China (Nos.22375059, 22005133, 51922039 and52273174)Shenzhen Science and Technology Program (No.RCJC20200714114434015)+1 种基金Science and Technology Innovation Program of Hunan Province (No.2020RC5033)National Key Research and Development Program of China (No.2020YFC1807302) for financial support。
文摘While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.
基金the National Natural Science Foundation of China(No.22175060,21975067)the National Basic Research Programs of China(No.2016YFA0300901)+4 种基金the National Science Foundation of China(No.11974105)the support from the U.S.National Science Foundation CREST Program(NSF No.HRD-1547723)the National Natural Science Foundation of China(No.51902346)Natural Science Foundation of China(No.21805077)the Natural Science Foundation of Hunan Province(No.2019JJ50075)。
文摘Semiconductor electrocatalysis with weak conductivity can accumulate extremely high carriers at semiconductor-electrolyte interface by self-gating effect,which strongly promotes electrocatalytic efficiency.The correlation between semiconductor carrier mobility and electrocatalysis performance is still unclear.Herein atomic-thin transition metal dichalcogenides based composites have been developed for hydrogen evolution reaction(HER)performed with on-chip microdevices.Electrical and electrochemical measurement of individual flack verified the key role of high carrier mobility for enhanced HER activity.Carrier mobility regulation further demonstrated its high dependence with HER performance under self-gating.Our study provides new insight into the carrier mobility of the semiconductor in the electrocatalysis,paving the way for designing high-performance semiconductor catalysts.
基金supported by the Changsha Municipal Natural Science Foundation(No.kq2014059)the School-Enterprise Cooperation Project(No.900201900966)。
文摘More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging material developed by photo-alignment technology,is a potential material for organizing the long-range ordered structure of azo dyes.However,little research has been done on LCP aligned azo dyes.This paper points out and solves a key problem that restricts the fabrication of high-precision arrays in guest[azo dye]-host[LCP]systems:the doping of dyes leads to disorder of the LCP during curing.After solving the problem,the relationship between the thickness of the LCP and the extinction ratio of the polarizing film was investigated,which effectively improved the extinction ratio.Alignment of azo dye molecules in the range of 2μm[0°-180°]and arrays of micropolarizers[0°,45°,90°,-45°]with 8μm×8μm pixel pitch was achieved by laser direct writing technology.The bending cycle test demonstrates the mechanical stability of the ultrathin flexible polarizer.The flexible patterned polarizer with robust chemical and mechanical stabilities provides a flexible way to capture the polarization of the light and highly integrated advanced flexible optoelectronic devices.
基金National Natural Science Foundation of China(NSFC)(11574079,61475102,61775056)Natural Science Foundation of Hunan Province(2017JJ1013)Ministry of Education of the People’s Republic of China(MOE)(6141A02033404)
文摘Ultrafast fiber lasers are in great demand for various applications, such as optical communication, spectroscopy,biomedical diagnosis, and industrial fabrication. Here, we report the highly stable femtosecond pulse generation from a MXene mode-locked fiber laser. We have prepared the high-quality Ti_3C_2 T_x nanosheets via the etching method, and characterized their ultrafast dynamics and broadband nonlinear optical responses. The obvious intensity-and wavelength-dependent nonlinear responses have been observed and investigated. In addition, a highly stable femtosecond fiber laser with signal-to-noise ratio up to 70.7 dB and central wavelength of 1567.3 nm has been delivered. The study may provide some valuable design guidelines for the development of ultrafast, broadband nonlinear optical modulators, and open new avenues toward advanced photonic devices based on MXenes.
基金supported by the National Natural Science Foundation of China(Grant Nos.61805115,and 61875132)the Shenzhen Science and Technology Innovation Commission(Grant No.JCYJ20190808143813399)。
文摘We provide a perspective review over the recent development of short-pulsed Raman fiber lasers(RFLs),which can provide laser emissions with flexible wavelengths for a variety of applications as well as an excellent platform to investigate various nonlinear pulse dynamics behaviors that cannot be captured in conventional rare-earth(RE)doped counterparts.Various pulse generation techniques have been explored in RFLs.However,the output pulse performance in terms of the pulse energy,duration and stability from short-pulsed RFLs is still inferior to their RE-doped counterparts despite significant advances made over the past few decades.Therefore,more efforts are required to improve these targets.In this review,we present a detailed overview of the short-pulsed RFLs based on different mechanisms from the principle to the experiment,including the Q-switching,gainswitching,mode-locking,synchronous pumping and other innovative techniques.In addition,Raman-induced pulse dynamics in ultrafast RFLs and RE-doped mode-locked fiber lasers(MLFLs)are briefly reviewed.Finally,a perspective outlook for the future ultrafast RFLs is provided based on their potential applications in industrial and scientific research areas.
基金supported by the National Natural Science Foundation of China (No. 61405058)the Natural Science Foundation of Hunan Province (No. 2017JJ2048)the Fundamental Research Funds for the Central Universities (No. 531118040112)
文摘In this Letter, a photonic crystal(PC) flat lens with a scatterer-size gradient is proposed, which simultaneously achieves imaging of the point source and sub-wavelength focusing of the plane wave in the first, second, and fifth bands. The imaging of the point source breaks through the diffraction limit in the second and fifth bands. The PC flat lens with the scatterer-size gradient is expected to be used in a new multifunctional optical imaging and focusing device, which improves the application potential of a PC flat lens.
基金supported by the National Natural Science Foundation of China(22175060 and 21975067)the Natural Science Foundation of Hunan Province,China(2021JJ10014 and 2021JJ30092)+4 种基金support from the National Natural Science Foundation of China(11974105)the National Basic Research Program of China(2016YFA0300901)support from the Natural Science Foundation of Jiangsu Province,China(BK20210729)the Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 Project and the Joint International Research Laboratory of Carbon-Based Functional Materials and Devices。
基金National Science Foundation,Grant/Award Number:MoMS 1930881China Scholarship Council,Grant/Award Number:201706130028+6 种基金National Natural Science Fund Foundation of China,Grant/Award Number:61775056Natural Science Foundation of Hunan Province,Grant/Award Number:2017JJ1013Research Fund of Science and Technology on Plasma Physics Laboratory,Grant/Award Number:6142A0403050717This work was supported by the National Natural Science Foundation of China(NSFC)(61775056)Natural Science Foundation of Hunan Province(2017JJ1013)Research Fund of Science and Technology on Plasma Physics Laboratory(6142A0403050717)The support provided by China Scholarship Council(CSC)during a visit of Jun Yi to Clemson University is acknowledged.This material is based upon work supported by the National Science Foundation under Grant No.MoMS 1930881.
文摘MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXene nanosheets dispersed in deionized water in the visible to near-infrared regime,highlighting the broadband nonlinear optical(NLO)response of Ti2CTx MXene.Using ultrafast pulsed laser excitation,the nonlinear refractive index n2 and the thirdorder nonlinear susceptibility χ^(3)monolayer of Ti2CTx MXene were measured to be^10^−13 m^2/W and ~10^−10 esu,respectively.Leveraging the large optical nonlinearity of Ti2CTx MXene,an all-optical modulator in the visible regime was fabricated based on the spatial cross-phase modulation effect.This work suggests that 2D MXenes are ideal broadband NLO materials with excellent prospects in NLO applications.
基金National Natural Science Foundation of China(NSFC)(11474132,11574079,61378004,61527823,61605166,61605219,61775056)Science and Technology Project of Jilin Province(20160520085JH)+1 种基金Natural Science Foundation of Hunan Province(2017JJ1013)Youth Innovation Promotion Association of the Chinese Academy of Sciences
文摘Mid-infrared pulsed lasers operating around the 3 μm wavelength regime are important for a wide range of applications including sensing, spectroscopy, imaging, etc. Despite the recent advances in technology, the lack of a nonlinear optical modulator operating in the mid-infrared regime remains a significant challenge. Here, we report the third-order nonlinear optical response of gold nanorods(GNRs) ranging from 800 nm to the mid-infrared regime(2810 nm) enabled by their size and overlapping behavior-dependent longitudinal surface plasmon resonance. In addition, we demonstrate a wavelength-tunable Er3+-doped fluoride fiber laser modulated by GNRs, which can deliver pulsed laser output, with the pulse duration down to 533 ns, tunable wavelength ranging from 2760.2 to 2810.0 nm, and spectral 3 d B bandwidth of about 1 nm. The experimental results not only validate the GNRs’ robust mid-infrared nonlinear optical response, but also manifest their application potential in high-performance broadband optoelectronic devices.