Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional...Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.展开更多
Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) has been recognized as a candidate solid electrolyte for high-safety Lianode based solid-state batteries because of its electro-chemical stability against Li-metal and high i...Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) has been recognized as a candidate solid electrolyte for high-safety Lianode based solid-state batteries because of its electro-chemical stability against Li-metal and high ionic conductivity. Solvent(e.g., isopropanol(IPA)) has been commonly applied for preparing LLZO powders and ceramics. However, the deterioration of the proton-exchange between LLZO and IPA/absorbed moisture during the mixing and tailoring route has aroused less attention. In this study, a solvent-free dry milling route was developed for preparing the LLZO powders and ceramics. For orthogonal four categories of samples prepared using solvent-free and IPA-assisted routes in the mixing and tailoring processes, the critical evaluation was conducted on the crystallinity, surficial morphology, and contamination of ascalcinated and as-tailored particles, the cross-sectional microstructure of green and sintered pellets,the morphology and electro-chemical properties of grain boundaries in ceramics, as well as the interfacial resistance and performance of Li anode based symmetric batteries. The wet route introduced Li-rich contaminations(e.g., Li OH·H)_(2)O and Li)_(2)CO)_(3)) onto the surfaces of LLZO particles and Li-Ta-O segregations at the adjacent and triangular grain boundaries. The LLZO solid electrolytes prepared through dry mixing in combination with the dry tailoring route without the use of any solvent were found to the optimal performance. The fundamental material properties in the whole LLZO preparation process were found, which are of guiding significance to the development of LLZO powder and ceramic production craft.展开更多
As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the...As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the specific capacities,intrinsic drawbacks such as poor initial Coulombic efficiency and low volumetric capacity could not be avoided.Herein,we propose a strategy to prepare carbon supported MoO_(2)spheres used for lithium-ion battery with high volumetric capacity density.A high initial Coulombic efficiency of 76.5%is obtained due to limited solid electrolyte interface film formed on the exposed surface.Meantime,the sample with an optimal carbon content and a proper structural strength reveals a higher reversible capacity of 956 mA h g^(-1)than the theoretical capacity of crystalline Mo O_(2)(838 mA h g^(-1))and a high capacity retention ratio of 96.4%after 100 cycles at 0.5 A g^(-1).And an effective compaction capacity density(under 5 MPa)of 670 mA h cm^(-3)of the spheres proves its potential value in practical applications.展开更多
The photonic spin Hall effect(SHE)in the reflection and refraction at an interface is very weak because of the weak spin-orbit interaction.Here,we report the observation of a giant photonic SHE in a dielectric-based m...The photonic spin Hall effect(SHE)in the reflection and refraction at an interface is very weak because of the weak spin-orbit interaction.Here,we report the observation of a giant photonic SHE in a dielectric-based metamaterial.The metamaterial is structured to create a coordinate-dependent,geometric Pancharatnam–Berry phase that results in an SHE with a spin-dependent splitting in momentum space.It is unlike the SHE that occurs in real space in the reflection and refraction at an interface,which results from the momentum-dependent gradient of the geometric Rytov–Vladimirskii–Berry phase.We theorize a unified description of the photonic SHE based on the two types of geometric phase gradient,and we experimentally measure the giant spin-dependent shift of the beam centroid produced by the metamaterial at a visible wavelength.Our results suggest that the structured metamaterial offers a potential method of manipulating spin-polarized photons and the orbital angular momentum of light and thus enables applications in spin-controlled nanophotonics.展开更多
In recent years,multi-wavelength fiber lasers play a significant role in plenty of fields,ranging from optical communications to mechanical processing and laser biomedicine,owing to their high beam quality,low cost,an...In recent years,multi-wavelength fiber lasers play a significant role in plenty of fields,ranging from optical communications to mechanical processing and laser biomedicine,owing to their high beam quality,low cost,and excellent heat dissipation properties.Benefitting from increasing maturity of optical elements,the multi-wavelength fiber laser has made rapid developments.In this review,we summarize and analyze diverse implementation methods covering continuous wave and pulsed fiber lasers at room temperature conditions:inserting an optical filter device and intensity-dependent loss structure in the resonant cavity,and applying ultrafast nonlinear optical response of materials and a dual-cavity structure.Finally,future challenges and perspectives of the multi-wavelength fiber laser are discussed and addressed.展开更多
Exposure to oxygen alters the physical and chemical properties of two-dimensional(2D)transition metal dichalcogenides(TMDs).In particular,oxygen in the ambient may influence the device stability of 2D TMDs over time.E...Exposure to oxygen alters the physical and chemical properties of two-dimensional(2D)transition metal dichalcogenides(TMDs).In particular,oxygen in the ambient may influence the device stability of 2D TMDs over time.Engineering the doping of 2D TMDs,especially hole doping is highly desirable towards their device function.Herein,controllable oxygen-induced p-type doping in a range of hexagonal(MoTe2,WSe2,MoSe2 and PtSe2)and pentagonal(PdSe2)2D TMDs are demonstrated.Scanning tunneling microscopy,electrical transport and X-ray photoelectron spectroscopy are used to probe the origin of oxygen-derived hole doping.Three mechanisms are postulated that contribute to the hole doping in 2D TMDs,namely charge transfer from absorbed oxygen molecules,surface oxides,and chalcogen atom substitution.This work provides insights into the doping effects of oxygen,enabling the engineering of 2D TMDs properties for nanoelectronic applications.展开更多
Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that f...Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.展开更多
To seek high signal-to-noise ratio(SNR) is critical but challenging for single-shot intense terahertz(THz)coherent detection. This paper presents an improved common-path spectral interferometer for single-shot THz det...To seek high signal-to-noise ratio(SNR) is critical but challenging for single-shot intense terahertz(THz)coherent detection. This paper presents an improved common-path spectral interferometer for single-shot THz detection with a single chirped pulse as the probe for THz electro-optic(EO) sampling. Here, the spectral interference occurs between the two orthogonal polarization components with a required relative time delay generated with only a birefringent plate after the EO sensor. Our experiments show that this interferometer can effectively suppress the noise usually suffered in a non-common-path interferometer. The measured single-shot SNR is up to 88.85, and the measured THz waveforms are independent of the orientation of the used Zn Te EO sensor, so it is easy to operate and the results are more reliable. These features mean that the interferometer is quite qualified for applications where strong THz pulses, usually with single-shot or low repetition rate, are indispensable.展开更多
Visible-light color flters using patterned nanostructures have attracted much interest due to their various advantages such as compactness,enhanced stability,and environmental friendliness compared with traditional pi...Visible-light color flters using patterned nanostructures have attracted much interest due to their various advantages such as compactness,enhanced stability,and environmental friendliness compared with traditional pigment or dye-based optical flters.While most existing studies are based on planar nanostructures with lateral variation in size,shape,and arrangement,the vertical dimension of structures is a long-ignored degree of freedom for the structural colors.Herein,we demonstrate a synthetic platform for transmissive color flter array by coordinated manipulations between height-varying nanocavities and their lateral flling fractions.Te thickness variation of those nanocavities has been fully deployed as an alternative degree of freedom,yielding vivid colors with wide gamut and excellent saturation.Experimental results show that the color-rendering capability of the pixelated nanocavities can be still retained as pixels are miniaturized to 500 nm.Crosstalk between closely spaced pixels of a Bayer color flter arrangement was calculated,showing minimal crosstalk for 1μm2 square subpixels.Our work provides an approach to designing and fabricating ultracompact color flter arrays for various potential applications including stained-glass microprints,microspectrometers,and high-resolution image sensing systems.展开更多
We report on a vortex laser chirped-pulse amplification(CPA)system that delivers pulses with a peak power of 45 TW.A focused intensity exceeding 1019 W/cm2 has been demonstrated for the first time by the vortex amplif...We report on a vortex laser chirped-pulse amplification(CPA)system that delivers pulses with a peak power of 45 TW.A focused intensity exceeding 1019 W/cm2 has been demonstrated for the first time by the vortex amplification scheme.Compared with other schemes of strong-field vortex generation with high energy flux but narrowband vortex-converting elements at the end of the laser,an important advantage of our scheme is that we can use a broadband but size-limited q-plate to realize broadband mode-converting in the front end of the CPA system,and achieve high-power amplification with a series of amplifiers.This method is low cost and can be easily implemented in an existing laser system.The results have verified the feasibility to obtain terawatt and even petawatt vortex laser amplification by a CPA system,which has important potential applications in strong-field laser physics,for example,generation of vortex particle beams with orbital angular momentum,fast ignition for inertial confinement fusion and simulation of the extreme astrophysical environment.展开更多
While aqueous Zn-Na hybrid batteries have garnered widespread attention because of their low cost and high safety,it is still challenging to achieve long cycle-life and stable discharge-voltage due to sluggish reactio...While aqueous Zn-Na hybrid batteries have garnered widespread attention because of their low cost and high safety,it is still challenging to achieve long cycle-life and stable discharge-voltage due to sluggish reaction kinetics,zinc dendrite formation,and side reactions.Herein,we design a Zn^(2+)/Na^(+) dual-salt battery,in which sodiation of the NVP cathode favors zinc intercalation under an energy threshold,leading to decoupled redox reactions on the cathode and anode.Systematic investigations of the electrolyte effects show that the ion intercalation mechanism and the kinetics in the mixture of triflate-and acetate-based electrolytes are superior to those in the common acetate-only electrolytes.As a result,we have achieved fast discharging capability,suppressed zinc dendrites,a stable discharge voltage at 1.45 V with small polarization,and nearly 100%Coulombic efficiency in the dual-salt mixture electrolyte with optimized concentration of 1 M Zn(OAc)_(2)+1 M NaCF_(3)SO_(3).This work demonstrates the importance of electrolyte regulation in aqueous dual-salt hybrid batteries for the energy storage.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance i...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance in TMDs based transistors seriously hinders their applications in complementary electronics.In this work,we show that an Ohmic homojunction n-type tungsten diselenide(WSe_(2))transistor is realized through spatially controlling cesium(Cs)doping region near the contacts.We find that the remarkable electron doping effect of Cs stimulates a semiconductor to metal(2H to 1T')phase transition in WSe_(2),and hence the formation of 2H-1T’hetero-phase contact.Our method significantly optimizes the WSe_(2) transport behavior with a perfect low subthreshold swing of-61 mV/dec and ultrahigh current on/off ratio exceeding-10^(9).Meanwhile,the electron mobility is enhanced by nearly 50 times.We elucidate that the ideal n-type behavior originates from the negligible Schottky barrier height of~19 meV and low contact resistance of-0.9Ωk·μm in the 2H-1T’homojunction device.Moreover,based on the Ohmic hetero-phase configuration,a WSe_(2) inverter is achieved with a high gain of~270 and low power consumption of-28 pW.Our findings envision Cs functionalization as an effective method to realize ideal Ohmic contact in 2D WSe_(2) transistors towards high performance complementary electronic devices.展开更多
Mechanoluminescent(ML) smart materials are expected to be used in stress sensors, new displays, and advanced flexible optoelectronic devices, because of their unique mechanical-to-light energy conversion properties. H...Mechanoluminescent(ML) smart materials are expected to be used in stress sensors, new displays, and advanced flexible optoelectronic devices, because of their unique mechanical-to-light energy conversion properties. However,the narrow-range ML emission characteristics of single materials limit their application scope. In this work, we report on the broadband multimodal emission in Sb-doped Ca Zn OS layered semiconductors. A series of Ca Zn OS layer-structured powders with different Sb^(3+) doping concentrations were synthesised using a high-temperature solid-phase method. The Ca Zn OS:Sb^(3+) phosphor achieved a wide range of ML spectra(400–900 nm), adjustable photoluminescence with double luminescent peaks located at 465 and 620 nm, and the X-rayinduced luminescence characteristics were systematically studied. We have also achieved ultra-broad warm white light ML emission of Sb^(3+) and Bi^(3+) co-doped samples. Therefore, it can be expected that these ML phosphors will be used in smart lighting, displays, visible stress sensors, and X-ray imaging and detections.展开更多
We have prepared the graphene∕MoS_(2) heterostructure by a hydrothermal method,and presented its nonlinear absorption parameters and application as a nonlinear optical modulator in the mid-infrared region.Using the n...We have prepared the graphene∕MoS_(2) heterostructure by a hydrothermal method,and presented its nonlinear absorption parameters and application as a nonlinear optical modulator in the mid-infrared region.Using the nonlinear optical modulator,stable passively Q-switched operation of an Er^(3+)-doped ZrF_(4)-BaF_(2)-LaF_(3)-AlF_(3)-NaF(ZBLAN)fiber laser at~2.8μm can be obtained.The Q-switched Er^(3+)-doped ZBLAN fiber laser can yield per-pulse energy up to 2.2μJ with the corresponding pulse width and pulse repetition rate of 1.9μs and 45 kHz,respectively.Our results indicate that the graphene∕MoS_(2) heterostructure can be a robust optical modulator for pulsed lasers in the mid-infrared spectral range.展开更多
The on-surface self-assembly of inorganic atomic clusters and organic molecules offers significant opportunities to design novel hybrid materials with tailored functionalities.By adopting the advantages from both inor...The on-surface self-assembly of inorganic atomic clusters and organic molecules offers significant opportunities to design novel hybrid materials with tailored functionalities.By adopting the advantages from both inorganic and organic components,the hybrid self-assembly molecules have shown great potential in future optoelectrical devices.Herein,we report the co-deposition of 4,8-diethynylbenzo[1,2-d-4,5-d0]bisoxazole(DEBBA)and Se atoms to produce a motif-adjustable organic–inorganic hybrid self-assembly system via the non-covalent interactions.By controlling the coverage of Se atoms,various chiral molecular networks containing Se,Se_(6),Se_(8),and terminal alkynes evolved on the Ag(111)surface.In particular,with the highest coverage of Se atoms,phase segregation into alternating one-dimensional chains of non-covalently bonded Se_(8) clusters and organic ligands has been noticed.The atom-coverage dependent evolution of self-assembly structures reflects the remarkable structural adaptability of Se clusters as building blocks based on the spontaneous resize to reach the maximum non-covalent interactions.This work has significantly extended the possibilities of flexible control in self-assembly nanostructures to enable more potential functions for broad applications.展开更多
Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materia...Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materials.Here,we reveal key insights of the OKE associated with 2D excitons.An admirably succinct formalism is derived for predicting the spectra and the magnitude of the nonlinear refractive index(n_(2))of 2D materials.The predicted n_(2)spectra are consistent with reported experimental data and exhibit pronounced excitonic resonances,which is distinctively different from bulk semiconductors.The n_(2) value is predicted to be 3×10^(−10)cm^(2)/W for a 2D layered perovskite at low temperature as 7 K,which is four orders of magnitude larger than those of bulk semiconductors.The superior OKE induced by 2D excitons would give rise to a narrow refractive index-near-zero region for intense laser light.Furthermore,we demonstrate that the 2D layered perovskite should exhibit the best OKE efficiency(W_(FOM)=1.02,T_(FOM)=0.14)at 1550 nm,meeting the material requirements for all-optical switching.Our findings deepen the understanding of the OKE of 2D semiconducting materials and pave the way for highly efficient all-optical excitonic devices.展开更多
Ultra-intense femtosecond vortex pulses can provide an opportunity to investigate the new phenomena with orbital angular momentum(OAM)involved in extreme cases.This paper reports a high gain optical vortex amplifier f...Ultra-intense femtosecond vortex pulses can provide an opportunity to investigate the new phenomena with orbital angular momentum(OAM)involved in extreme cases.This paper reports a high gain optical vortex amplifier for intense femtosecond vortex pulses generation.Traditional regeneration amplifiers can offer high gain for Gaussian mode pulses but cannot amplify optical vortex pulses while maintaining the phase singularity because of mode competition.Here,we present a regeneration amplifier with a ring-shaped pump.By controlling the radius of the pump,the system can realize the motivation of the Laguerre–Gaussian[LG0,1(−1)]mode and the suppression of the Gaussian mode.Without seeds,the amplifier has a donut-shaped output containing two opposite OAM states simultaneously,as our prediction by simulation.If seeded by a pulse of a topologic charge of 1 or−1,the system will output an amplified LG0,1(−1)mode pulse with the same topologic charge as the seed.To our knowledge,this amplifier can offer the highest gain as 1.45×106 for optical vortex amplification.Finally,we obtain a 1.8 mJ,51 fs compressed optical vortex seeded from a 2 nJ optical vortex.展开更多
基金the financial support from Natural Science Foundation of Jiangsu Province(No.BK20170005)the National Natural Science Foundation of China(No.21872100)+1 种基金Singapore MOE Grants MOE2019-T2-1-002 and R143-000-A43-114,Fundamental Research Foundation of Shenzhen(Nos.JCYJ20190808152607389 and JCYJ20170817100405375)Shenzhen Peacock Plan(No.KQTD2016053112042971).
文摘Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.
基金the financial support from the National Key R&D Project (2018YFE0181300)the National Natural Science Foundation of China (Grant No. 52102284)+2 种基金the China Postdoctoral Science Foundation (2020M682871)the Guangdong Natural Science Funds (2019A1515010675)the Science and Technology Project of Shenzhen (JCYJ20190808142209376 and JCYJ20210324094206019)。
文摘Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) has been recognized as a candidate solid electrolyte for high-safety Lianode based solid-state batteries because of its electro-chemical stability against Li-metal and high ionic conductivity. Solvent(e.g., isopropanol(IPA)) has been commonly applied for preparing LLZO powders and ceramics. However, the deterioration of the proton-exchange between LLZO and IPA/absorbed moisture during the mixing and tailoring route has aroused less attention. In this study, a solvent-free dry milling route was developed for preparing the LLZO powders and ceramics. For orthogonal four categories of samples prepared using solvent-free and IPA-assisted routes in the mixing and tailoring processes, the critical evaluation was conducted on the crystallinity, surficial morphology, and contamination of ascalcinated and as-tailored particles, the cross-sectional microstructure of green and sintered pellets,the morphology and electro-chemical properties of grain boundaries in ceramics, as well as the interfacial resistance and performance of Li anode based symmetric batteries. The wet route introduced Li-rich contaminations(e.g., Li OH·H)_(2)O and Li)_(2)CO)_(3)) onto the surfaces of LLZO particles and Li-Ta-O segregations at the adjacent and triangular grain boundaries. The LLZO solid electrolytes prepared through dry mixing in combination with the dry tailoring route without the use of any solvent were found to the optimal performance. The fundamental material properties in the whole LLZO preparation process were found, which are of guiding significance to the development of LLZO powder and ceramic production craft.
基金financially supported by the National Natural Science Foundation of China(21975250)the National Key R&D Program of China(2017YFE0198100)+1 种基金the Hightech Research Key laboratory of Zhenjiang(SS2018002)Jiangsu Post-doctoral Research Funding Program(2020Z257)。
文摘As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the specific capacities,intrinsic drawbacks such as poor initial Coulombic efficiency and low volumetric capacity could not be avoided.Herein,we propose a strategy to prepare carbon supported MoO_(2)spheres used for lithium-ion battery with high volumetric capacity density.A high initial Coulombic efficiency of 76.5%is obtained due to limited solid electrolyte interface film formed on the exposed surface.Meantime,the sample with an optimal carbon content and a proper structural strength reveals a higher reversible capacity of 956 mA h g^(-1)than the theoretical capacity of crystalline Mo O_(2)(838 mA h g^(-1))and a high capacity retention ratio of 96.4%after 100 cycles at 0.5 A g^(-1).And an effective compaction capacity density(under 5 MPa)of 670 mA h cm^(-3)of the spheres proves its potential value in practical applications.
基金This research was partially supported by the National Natural Science Foundation of China(Grants No.11274106,No.11474089 and No.11447010)the China Postdoctoral Science Foundation(Grant No.2014M562198)+1 种基金the Scientific Research Fund of Hunan Provincial Education Department of China(Grant No.13B003)the Natural Science Foundation of Hunan Province(Grant No.2015JJ3026).
文摘The photonic spin Hall effect(SHE)in the reflection and refraction at an interface is very weak because of the weak spin-orbit interaction.Here,we report the observation of a giant photonic SHE in a dielectric-based metamaterial.The metamaterial is structured to create a coordinate-dependent,geometric Pancharatnam–Berry phase that results in an SHE with a spin-dependent splitting in momentum space.It is unlike the SHE that occurs in real space in the reflection and refraction at an interface,which results from the momentum-dependent gradient of the geometric Rytov–Vladimirskii–Berry phase.We theorize a unified description of the photonic SHE based on the two types of geometric phase gradient,and we experimentally measure the giant spin-dependent shift of the beam centroid produced by the metamaterial at a visible wavelength.Our results suggest that the structured metamaterial offers a potential method of manipulating spin-polarized photons and the orbital angular momentum of light and thus enables applications in spin-controlled nanophotonics.
基金partially supported by the Science and Technology Development Fund,Macao Special Administration Region(SAR)(Nos.007/2017/A1 and 132/2017/A3)National Natural Science Foundation of China(NSFC)(Nos.61875138,61435010,61775142,and 6181101252)+1 种基金Science and Technology Innovation Commission of Shenzhen(Nos.KQTD2015032416270385,JCYJ20150625103619275,and JCYJ20170811093453105)Shenzhen Basic Research Project on Subject Layout(No.JCYJ20170412105812811)。
文摘In recent years,multi-wavelength fiber lasers play a significant role in plenty of fields,ranging from optical communications to mechanical processing and laser biomedicine,owing to their high beam quality,low cost,and excellent heat dissipation properties.Benefitting from increasing maturity of optical elements,the multi-wavelength fiber laser has made rapid developments.In this review,we summarize and analyze diverse implementation methods covering continuous wave and pulsed fiber lasers at room temperature conditions:inserting an optical filter device and intensity-dependent loss structure in the resonant cavity,and applying ultrafast nonlinear optical response of materials and a dual-cavity structure.Finally,future challenges and perspectives of the multi-wavelength fiber laser are discussed and addressed.
基金This work was financially supported by the National Natural Science Foundation of China(No.51472164)Shenzhen Peacock Plan(No.KQTD2016053112042971)+3 种基金the Educational Commission of Guangdong Province(Nos.2015KGJHZ006 and 2016KCXTD006)the Science and Technology Planning Project of Guangdong Province(No.2016B050501005)A.T.S.W.acknowledges funding support from MOE Tier 2 grant R 144-000-382-112,A*STAR Pharos Program(No.1527300025)facility support from the NUS Centre for Advanced 2D Materials(CA2DM).
文摘Exposure to oxygen alters the physical and chemical properties of two-dimensional(2D)transition metal dichalcogenides(TMDs).In particular,oxygen in the ambient may influence the device stability of 2D TMDs over time.Engineering the doping of 2D TMDs,especially hole doping is highly desirable towards their device function.Herein,controllable oxygen-induced p-type doping in a range of hexagonal(MoTe2,WSe2,MoSe2 and PtSe2)and pentagonal(PdSe2)2D TMDs are demonstrated.Scanning tunneling microscopy,electrical transport and X-ray photoelectron spectroscopy are used to probe the origin of oxygen-derived hole doping.Three mechanisms are postulated that contribute to the hole doping in 2D TMDs,namely charge transfer from absorbed oxygen molecules,surface oxides,and chalcogen atom substitution.This work provides insights into the doping effects of oxygen,enabling the engineering of 2D TMDs properties for nanoelectronic applications.
基金supported by the National 973 Program of China (Grant No. 2012CB315701)the National Natural Science Foundation of China (Grant Nos. 61205125, 61222505, and 61475102)
文摘Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.
基金National Natural Science Foundation of China(NSFC)(61490710,61775142,61705132)Science and Technology Planning Project of Guangdong Province(2016B050501005)Specialized Research Fund for the Shenzhen Strategic Emerging Industries Development(JCYJ20150324141711651,JCYJ20150525092941064,JCYJ20170412105812811)
文摘To seek high signal-to-noise ratio(SNR) is critical but challenging for single-shot intense terahertz(THz)coherent detection. This paper presents an improved common-path spectral interferometer for single-shot THz detection with a single chirped pulse as the probe for THz electro-optic(EO) sampling. Here, the spectral interference occurs between the two orthogonal polarization components with a required relative time delay generated with only a birefringent plate after the EO sensor. Our experiments show that this interferometer can effectively suppress the noise usually suffered in a non-common-path interferometer. The measured single-shot SNR is up to 88.85, and the measured THz waveforms are independent of the orientation of the used Zn Te EO sensor, so it is easy to operate and the results are more reliable. These features mean that the interferometer is quite qualified for applications where strong THz pulses, usually with single-shot or low repetition rate, are indispensable.
基金Te authors gratefully acknowledge the fnancial support from the National Natural Science Foundation of China(Grant nos.51722503 and 11574078).
文摘Visible-light color flters using patterned nanostructures have attracted much interest due to their various advantages such as compactness,enhanced stability,and environmental friendliness compared with traditional pigment or dye-based optical flters.While most existing studies are based on planar nanostructures with lateral variation in size,shape,and arrangement,the vertical dimension of structures is a long-ignored degree of freedom for the structural colors.Herein,we demonstrate a synthetic platform for transmissive color flter array by coordinated manipulations between height-varying nanocavities and their lateral flling fractions.Te thickness variation of those nanocavities has been fully deployed as an alternative degree of freedom,yielding vivid colors with wide gamut and excellent saturation.Experimental results show that the color-rendering capability of the pixelated nanocavities can be still retained as pixels are miniaturized to 500 nm.Crosstalk between closely spaced pixels of a Bayer color flter arrangement was calculated,showing minimal crosstalk for 1μm2 square subpixels.Our work provides an approach to designing and fabricating ultracompact color flter arrays for various potential applications including stained-glass microprints,microspectrometers,and high-resolution image sensing systems.
基金supported by the National Natural Science Foundation of China(Nos.92050203,61925507,12174264,12004261,62075138,and 61827815)the Natural Science Foundation of Guangdong Province(Nos.2021A1515011909 and 2022A1515011457)the Shenzhen Fundamental Research Projects(Nos.JCYJ20200109105606426,JCYJ20190808164007485,JCYJ20190808121817100,JCYJ20190808143419622,and JCYJ20190808115601653).
文摘We report on a vortex laser chirped-pulse amplification(CPA)system that delivers pulses with a peak power of 45 TW.A focused intensity exceeding 1019 W/cm2 has been demonstrated for the first time by the vortex amplification scheme.Compared with other schemes of strong-field vortex generation with high energy flux but narrowband vortex-converting elements at the end of the laser,an important advantage of our scheme is that we can use a broadband but size-limited q-plate to realize broadband mode-converting in the front end of the CPA system,and achieve high-power amplification with a series of amplifiers.This method is low cost and can be easily implemented in an existing laser system.The results have verified the feasibility to obtain terawatt and even petawatt vortex laser amplification by a CPA system,which has important potential applications in strong-field laser physics,for example,generation of vortex particle beams with orbital angular momentum,fast ignition for inertial confinement fusion and simulation of the extreme astrophysical environment.
基金financially supported by the Hightech Research Key laboratory of Zhenjiang(SS2018002)Jiangsu Postdoctoral Research Funding Program(2020Z257)+3 种基金support from MOE Tier 1 grant(RG 157/19)from the China-Singapore International Joint Research Institute(204-A018002)financial support from the Guangdong Natural Science Funds(2019A1515010675)the Science and Technology Project of Shenzhen(JCYJ20210324094206019,KQJSCX20180328094001794)。
文摘While aqueous Zn-Na hybrid batteries have garnered widespread attention because of their low cost and high safety,it is still challenging to achieve long cycle-life and stable discharge-voltage due to sluggish reaction kinetics,zinc dendrite formation,and side reactions.Herein,we design a Zn^(2+)/Na^(+) dual-salt battery,in which sodiation of the NVP cathode favors zinc intercalation under an energy threshold,leading to decoupled redox reactions on the cathode and anode.Systematic investigations of the electrolyte effects show that the ion intercalation mechanism and the kinetics in the mixture of triflate-and acetate-based electrolytes are superior to those in the common acetate-only electrolytes.As a result,we have achieved fast discharging capability,suppressed zinc dendrites,a stable discharge voltage at 1.45 V with small polarization,and nearly 100%Coulombic efficiency in the dual-salt mixture electrolyte with optimized concentration of 1 M Zn(OAc)_(2)+1 M NaCF_(3)SO_(3).This work demonstrates the importance of electrolyte regulation in aqueous dual-salt hybrid batteries for the energy storage.
基金the financial support from the National Natural Science Foundation of China(Nos.U2032147,21872100 and 62004128)Singapore MOE Grants MOE-2019-T2-1-002+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB30000000)Fundamental Research Foundation of Shenzhen(Nos.JCYJ20170817100405375 and JCYJ20190808152607389).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance in TMDs based transistors seriously hinders their applications in complementary electronics.In this work,we show that an Ohmic homojunction n-type tungsten diselenide(WSe_(2))transistor is realized through spatially controlling cesium(Cs)doping region near the contacts.We find that the remarkable electron doping effect of Cs stimulates a semiconductor to metal(2H to 1T')phase transition in WSe_(2),and hence the formation of 2H-1T’hetero-phase contact.Our method significantly optimizes the WSe_(2) transport behavior with a perfect low subthreshold swing of-61 mV/dec and ultrahigh current on/off ratio exceeding-10^(9).Meanwhile,the electron mobility is enhanced by nearly 50 times.We elucidate that the ideal n-type behavior originates from the negligible Schottky barrier height of~19 meV and low contact resistance of-0.9Ωk·μm in the 2H-1T’homojunction device.Moreover,based on the Ohmic hetero-phase configuration,a WSe_(2) inverter is achieved with a high gain of~270 and low power consumption of-28 pW.Our findings envision Cs functionalization as an effective method to realize ideal Ohmic contact in 2D WSe_(2) transistors towards high performance complementary electronic devices.
基金supported by the National Natural Science Foundation of China (61875136 and 52002246)the Fundamental Research Project of Guangdong Province (2020A1515011315)+2 种基金Shenzhen Fundamental Research Project (JCYJ20190808170601664)the Science and Technology Innovation Project of Shenzhen Excellent Talents (RCBS20200714114919006)the Scientific Research Foundation as Phase II construction of high-level University for the Youth Scholars of Shenzhen University 2019 (000002110223)。
文摘Mechanoluminescent(ML) smart materials are expected to be used in stress sensors, new displays, and advanced flexible optoelectronic devices, because of their unique mechanical-to-light energy conversion properties. However,the narrow-range ML emission characteristics of single materials limit their application scope. In this work, we report on the broadband multimodal emission in Sb-doped Ca Zn OS layered semiconductors. A series of Ca Zn OS layer-structured powders with different Sb^(3+) doping concentrations were synthesised using a high-temperature solid-phase method. The Ca Zn OS:Sb^(3+) phosphor achieved a wide range of ML spectra(400–900 nm), adjustable photoluminescence with double luminescent peaks located at 465 and 620 nm, and the X-rayinduced luminescence characteristics were systematically studied. We have also achieved ultra-broad warm white light ML emission of Sb^(3+) and Bi^(3+) co-doped samples. Therefore, it can be expected that these ML phosphors will be used in smart lighting, displays, visible stress sensors, and X-ray imaging and detections.
基金supported by the China Postdoctoral Science Foundation(No.2017M620349)the National Natural Science Foundation of China(Nos.61605166,11374251,and 61505124)+1 种基金the Research Foundation of Education Bureau of Hunan Province,China(No.17C1519)the Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT 17R91)
文摘We have prepared the graphene∕MoS_(2) heterostructure by a hydrothermal method,and presented its nonlinear absorption parameters and application as a nonlinear optical modulator in the mid-infrared region.Using the nonlinear optical modulator,stable passively Q-switched operation of an Er^(3+)-doped ZrF_(4)-BaF_(2)-LaF_(3)-AlF_(3)-NaF(ZBLAN)fiber laser at~2.8μm can be obtained.The Q-switched Er^(3+)-doped ZBLAN fiber laser can yield per-pulse energy up to 2.2μJ with the corresponding pulse width and pulse repetition rate of 1.9μs and 45 kHz,respectively.Our results indicate that the graphene∕MoS_(2) heterostructure can be a robust optical modulator for pulsed lasers in the mid-infrared spectral range.
基金the Guangdong Basic and Applied Basic Research Foundation(Nos.2019A1515110819 and 2020A1515010767)NRF-CRP grant“Two Dimensional Covalent Organic Framework:Synthesis and Applications”(No.NRF-CRP16-2015-02,funded by National Research Foundation,Prime Minister’s Office,Singapore)+1 种基金the Shenzhen Peacock Plan(No.KQTD2016053112042971)the National Natural Science Foundation of China(Nos.21802067 and 21771156).
文摘The on-surface self-assembly of inorganic atomic clusters and organic molecules offers significant opportunities to design novel hybrid materials with tailored functionalities.By adopting the advantages from both inorganic and organic components,the hybrid self-assembly molecules have shown great potential in future optoelectrical devices.Herein,we report the co-deposition of 4,8-diethynylbenzo[1,2-d-4,5-d0]bisoxazole(DEBBA)and Se atoms to produce a motif-adjustable organic–inorganic hybrid self-assembly system via the non-covalent interactions.By controlling the coverage of Se atoms,various chiral molecular networks containing Se,Se_(6),Se_(8),and terminal alkynes evolved on the Ag(111)surface.In particular,with the highest coverage of Se atoms,phase segregation into alternating one-dimensional chains of non-covalently bonded Se_(8) clusters and organic ligands has been noticed.The atom-coverage dependent evolution of self-assembly structures reflects the remarkable structural adaptability of Se clusters as building blocks based on the spontaneous resize to reach the maximum non-covalent interactions.This work has significantly extended the possibilities of flexible control in self-assembly nanostructures to enable more potential functions for broad applications.
基金National University of Singapore and Ministry of Education of the Singapore government(R-144-000-401-114,R-144-000-445-114)China Postdoctoral Science Foundation(2020M672763)+1 种基金Science and Technology Innovation Commission of Shenzhen(JCYJ20170302153323978,JCYJ20170410171958839)Education Commission of Guangdong Province(2016KCXTD006).
文摘Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materials.Here,we reveal key insights of the OKE associated with 2D excitons.An admirably succinct formalism is derived for predicting the spectra and the magnitude of the nonlinear refractive index(n_(2))of 2D materials.The predicted n_(2)spectra are consistent with reported experimental data and exhibit pronounced excitonic resonances,which is distinctively different from bulk semiconductors.The n_(2) value is predicted to be 3×10^(−10)cm^(2)/W for a 2D layered perovskite at low temperature as 7 K,which is four orders of magnitude larger than those of bulk semiconductors.The superior OKE induced by 2D excitons would give rise to a narrow refractive index-near-zero region for intense laser light.Furthermore,we demonstrate that the 2D layered perovskite should exhibit the best OKE efficiency(W_(FOM)=1.02,T_(FOM)=0.14)at 1550 nm,meeting the material requirements for all-optical switching.Our findings deepen the understanding of the OKE of 2D semiconducting materials and pave the way for highly efficient all-optical excitonic devices.
基金National Natural Science Foundation of China(61490710,61705132,61775142)Shenzhen Basic Research Project on Subject Layout(JCYJ20170412105812811)Shenzhen Basic Research Projects(JCYJ20190808115601653,JCYJ20190808164007485).
文摘Ultra-intense femtosecond vortex pulses can provide an opportunity to investigate the new phenomena with orbital angular momentum(OAM)involved in extreme cases.This paper reports a high gain optical vortex amplifier for intense femtosecond vortex pulses generation.Traditional regeneration amplifiers can offer high gain for Gaussian mode pulses but cannot amplify optical vortex pulses while maintaining the phase singularity because of mode competition.Here,we present a regeneration amplifier with a ring-shaped pump.By controlling the radius of the pump,the system can realize the motivation of the Laguerre–Gaussian[LG0,1(−1)]mode and the suppression of the Gaussian mode.Without seeds,the amplifier has a donut-shaped output containing two opposite OAM states simultaneously,as our prediction by simulation.If seeded by a pulse of a topologic charge of 1 or−1,the system will output an amplified LG0,1(−1)mode pulse with the same topologic charge as the seed.To our knowledge,this amplifier can offer the highest gain as 1.45×106 for optical vortex amplification.Finally,we obtain a 1.8 mJ,51 fs compressed optical vortex seeded from a 2 nJ optical vortex.
