We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse ...We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse with a plasma and one or multiple photon beams supplied by intense lasers.Owing to nonlinear effects,two-or multiphoton absorption dominates over the conventional multistep one-photon process for an optimized γ flash.Moreover,this nonlinear effect can be greatly enhanced with the help of externally supplied low-energy photons coming from another laser.These low-energy photons act such that the effective cross-section experienced by the γ photons becomes tunable,growing with the intensity I_(0) of the beam.Assuming I_(0)~10^(18) W·cm^(-2) for the photon beam,an effective cross-section as large as 10^(-21)-10^(-28) cm^(2) for the γ photons can be achieved.Thus,with state-of-the-art 10 PW laser facilities,the yields from two-photon absorption can reach 10^(6)-10^(9) isomers per shot for selected states that are separated from their ground state by E2 transitions.Similar yields for transitions with higher multipolarities can be accommodated by multiphoton absorption with additional photons provided.展开更多
Semiconductor quantum dots(QDs),as high-performance materials,play an essential role in contemporary industry,mainly due to their high photoluminescent quantum yield,wide absorption characteristics,and size-dependent ...Semiconductor quantum dots(QDs),as high-performance materials,play an essential role in contemporary industry,mainly due to their high photoluminescent quantum yield,wide absorption characteristics,and size-dependent light emission.It is essential to construct well-defined micro-/nano-structures using QDs as building blocks for micro-optic applications.However,the fabrication of stable QDs with designed functional structures has long been challenging.Here,we propose a strategy for three-dimensional direct lithography of desired QDs within a hybrid medium with specific protection properties.The acrylate-functionalized hybrid precursors enable local crosslinking through ultrafast laser-induced multiphoton absorption,achieving sub-100 nm resolution surpassing the diffraction limit.The printed micro-/nano-structures possess thermal stability up to 600℃,which can be transformed to inorganic architectures with a volume shrinkage.Due to the encapsulated QDs within the densely silicon-oxygen molecular networks,the functional structures demonstrate good stability against ultraviolet irradiation,corrosive solutions,and elevated temperatures.Based on hybrid3D nanolithography,bicolor multilayer micro-/nano-structures are manufactured for applications in 3D data storage and optical information encryption.This research presents an effective strategy for the fabrication of desired QD micro-/nano-structures,supporting the development of stable functional device applications.展开更多
Perovskite nanocrystals(NCs) with high two-photon absorption(TPA) cross-section are of great interest due to their potential applications in three-dimensional optical data storage and multiphoton fluorescence microsco...Perovskite nanocrystals(NCs) with high two-photon absorption(TPA) cross-section are of great interest due to their potential applications in three-dimensional optical data storage and multiphoton fluorescence microscopy. Among various perovskite materials, FAPbBr_(3) NCs show a better development prospect due to their excellent stability. However, there are few reports on their nonlinear optical properties. In this work, the nonlinear optical behavior of FAPbBr_(3) NCs is studied.The methods of multiphoton absorption photoluminescence saturation and open aperture Z-scan technique were applied to determine the TPA cross-section of FAPbBr_(3)NCs, which was around 2.76 × 10^(-45)cm^(4)·s·photon^(-1) at 800 nm. In addition,temperature-dependent photoluminescence induced by TPA was investigated, and the small longitudinal optical phonon energy and electron–phonon coupling strength was obtained, which confirm the weak Pb–Br interaction. Meanwhile, it is found that the exciton binding energy in FAPbBr_(3) NCs was 69.668 me V, which may be ascribed to the strong hydrogen bond interaction. It is expected that our findings will promote the application of FAPbBr_(3) NCs in optoelectronic devices.展开更多
The development of nonlinear optical materials with strong multiphoton absorption(MPA)is crucial for the design of ultrafast nonlinear optical devices,such as optical limiters and all-optical switchers.In this study,w...The development of nonlinear optical materials with strong multiphoton absorption(MPA)is crucial for the design of ultrafast nonlinear optical devices,such as optical limiters and all-optical switchers.In this study,we present the wavelengthdependent coefficients of two-photon absorption(2PA)and three-photon absorption(3PA)in a Ga S film across a broad range of wavelengths from 540 to 1600 nm.The observed dispersions in the 2PA and 3PA coefficients align well with the widely used two-band approximation model applied to direct bandgap semiconductors.Notably,the Ga S film exhibits exceptional MPA properties with a maximum 2PA coefficient of 19.89 cm/GW at 620 nm and a maximum 3PA coefficient of4.88 cm^(3)/GW2at 1500 nm.The Ga S film surpasses those found in traditional wide-bandgap semiconductors like β-Ga_(2)O_(3),Ga N,Zn O,and Zn S while remaining comparable to monolayer Mo S_(2),Cs Pb Br_(3),and(C_(4)H_(9)NH_(3))_(2)Pb Br_(4) perovskites.By employing a simplified two-energy-level model analysis,our results indicate that these large MPA coefficients are primarily determined by the remarkable absorption cross sections,which are approximately 4.82×10^(-52)·cm^(4)·s·photon^(-1)at 620 nm for 2PAand 8.17×10^(-80)·cm^(6)·s^(2)·photon^(-2)at 1500 nm for 3PA.Our findings demonstrate significant potential for utilizing Ga S films in nonlinear optical applications.展开更多
In this paper, we put emphasis on the analysis the mechanism of the photon induced frequency conversion β BaB 2O 4 crystal inside a borate glass using femtosecond laser. Because of the nature of femtosecond laser...In this paper, we put emphasis on the analysis the mechanism of the photon induced frequency conversion β BaB 2O 4 crystal inside a borate glass using femtosecond laser. Because of the nature of femtosecond laser's ultra short pulse duration and high energy density, in essence the laser glass interaction mechanism is changed. Based on multiphoton ionization, collisional ionization and the network depolymerization in the borate glass, production of the plasma drives the microstructure rearrangement near the laser beam focusing area. From the structure of glass and crystal analysis, we conclude that the complicated borate groups containing BO 3 and BO 4 units inside the glass are converted into(B 3O 6) -3 anion rings.展开更多
ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with ...ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with small grain sizes and high specific surface areas remains challenging.While breakthroughs in laser-based synthesis techniques have enabled simultaneous growth and patterning of these materials,device integration restrictions owing to pre-prepared laser-absorbing layers remain a severe issue.Herein,we report a single-step femtosecond laser direct writing(FsLDW)method for fabricating ZnO nanomaterial micropatterns with a minimum linewidth of less than 1μm without requiring laser-absorbing layers.Furthermore,utilizing the grain-size modulation effect of glycerol,we successfully reduced the grain size and addressed the challenges of discontinuity and non-uniform product formation during FsLDW.Using this technique,we successfully fabricated a series of 2 micro-photodetectors with exceptional performance,a switching ratio of 105,and a responsivity of 10 A/W.Notably,the devices exhibited an ultralow dark current of less than 10 pA,more than one order of magnitude lower than the dark current of ZnO photodetectors under the same bias voltage—crucial for enhancing the signal-to-noise ratio and reducing the power consumption of photodetectors.The proposed method could be extended to preparing other metal-oxide nanomaterials and devices,thus providing new opportunities for developing customized,miniaturized,and integrated functional devices.展开更多
基金supported by the Extreme Light Infrastructure Nuclear Physics(ELI-NP)Phase Ⅱ,a project co-financed by the Romanian Government and the European Union through the European Regional Development Fund—the Competitiveness Operational Programme(1/07.07.2016,COP,ID 1334)the Romanian Ministry of Research and Innovation:PN23210105(Phase 2,the Program Nucleu),ELI-RO grants Proiectul ELI-RO/RDI_2024_AMAP,ELI-RO_RDI_2024_LaLuThe,ELIRO_RDI_2024_SPARC+4 种基金ELI10/01.10.2020 of the Romanian Governmentthe European Union,the Romanian Governmentthe Health Program,within the project“Medical Applications of High-Power Lasers—Dr.LASER”SMIS Code:326475the IOSIN funds for research infrastructures of national interest.
文摘We propose a novel scheme for the population and depletion of nuclear isomers.This scheme combines the γ photons with energiesà 10 keV emitted during the interaction of a contemporary high-intensity laser pulse with a plasma and one or multiple photon beams supplied by intense lasers.Owing to nonlinear effects,two-or multiphoton absorption dominates over the conventional multistep one-photon process for an optimized γ flash.Moreover,this nonlinear effect can be greatly enhanced with the help of externally supplied low-energy photons coming from another laser.These low-energy photons act such that the effective cross-section experienced by the γ photons becomes tunable,growing with the intensity I_(0) of the beam.Assuming I_(0)~10^(18) W·cm^(-2) for the photon beam,an effective cross-section as large as 10^(-21)-10^(-28) cm^(2) for the γ photons can be achieved.Thus,with state-of-the-art 10 PW laser facilities,the yields from two-photon absorption can reach 10^(6)-10^(9) isomers per shot for selected states that are separated from their ground state by E2 transitions.Similar yields for transitions with higher multipolarities can be accommodated by multiphoton absorption with additional photons provided.
基金supported by the National Key Research and Development Program of China(2024YFB3213700)Shenzhen Science and Technology Program(Shenzhen Key Laboratory of Ultrafast Laser Micro/Nano Manufacturing ZDSYS20220606100405013)+3 种基金Natural Science Foundation of Guangdong Province(2022B1515120061)National Natural Science Foundation of China(T2421003)Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20231722)Research Team Cultivation Program of Shenzhen University(2023QNT009)。
文摘Semiconductor quantum dots(QDs),as high-performance materials,play an essential role in contemporary industry,mainly due to their high photoluminescent quantum yield,wide absorption characteristics,and size-dependent light emission.It is essential to construct well-defined micro-/nano-structures using QDs as building blocks for micro-optic applications.However,the fabrication of stable QDs with designed functional structures has long been challenging.Here,we propose a strategy for three-dimensional direct lithography of desired QDs within a hybrid medium with specific protection properties.The acrylate-functionalized hybrid precursors enable local crosslinking through ultrafast laser-induced multiphoton absorption,achieving sub-100 nm resolution surpassing the diffraction limit.The printed micro-/nano-structures possess thermal stability up to 600℃,which can be transformed to inorganic architectures with a volume shrinkage.Due to the encapsulated QDs within the densely silicon-oxygen molecular networks,the functional structures demonstrate good stability against ultraviolet irradiation,corrosive solutions,and elevated temperatures.Based on hybrid3D nanolithography,bicolor multilayer micro-/nano-structures are manufactured for applications in 3D data storage and optical information encryption.This research presents an effective strategy for the fabrication of desired QD micro-/nano-structures,supporting the development of stable functional device applications.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62174079)the Fund from the Science, Technology, and Innovation Commission of Shenzhen Municipality (Grant Nos. JCYJ20220530113015035, JCYJ20210324120204011, JCYJ20190808121211510, and KQTD2015071710313656)。
文摘Perovskite nanocrystals(NCs) with high two-photon absorption(TPA) cross-section are of great interest due to their potential applications in three-dimensional optical data storage and multiphoton fluorescence microscopy. Among various perovskite materials, FAPbBr_(3) NCs show a better development prospect due to their excellent stability. However, there are few reports on their nonlinear optical properties. In this work, the nonlinear optical behavior of FAPbBr_(3) NCs is studied.The methods of multiphoton absorption photoluminescence saturation and open aperture Z-scan technique were applied to determine the TPA cross-section of FAPbBr_(3)NCs, which was around 2.76 × 10^(-45)cm^(4)·s·photon^(-1) at 800 nm. In addition,temperature-dependent photoluminescence induced by TPA was investigated, and the small longitudinal optical phonon energy and electron–phonon coupling strength was obtained, which confirm the weak Pb–Br interaction. Meanwhile, it is found that the exciton binding energy in FAPbBr_(3) NCs was 69.668 me V, which may be ascribed to the strong hydrogen bond interaction. It is expected that our findings will promote the application of FAPbBr_(3) NCs in optoelectronic devices.
基金supported by the National Natural Science Foundation of China(Nos.12261141662 and 12074311)the 2023 Graduate Education Comprehensive Reform Research and Practice Project(No.ZG2023009)。
文摘The development of nonlinear optical materials with strong multiphoton absorption(MPA)is crucial for the design of ultrafast nonlinear optical devices,such as optical limiters and all-optical switchers.In this study,we present the wavelengthdependent coefficients of two-photon absorption(2PA)and three-photon absorption(3PA)in a Ga S film across a broad range of wavelengths from 540 to 1600 nm.The observed dispersions in the 2PA and 3PA coefficients align well with the widely used two-band approximation model applied to direct bandgap semiconductors.Notably,the Ga S film exhibits exceptional MPA properties with a maximum 2PA coefficient of 19.89 cm/GW at 620 nm and a maximum 3PA coefficient of4.88 cm^(3)/GW2at 1500 nm.The Ga S film surpasses those found in traditional wide-bandgap semiconductors like β-Ga_(2)O_(3),Ga N,Zn O,and Zn S while remaining comparable to monolayer Mo S_(2),Cs Pb Br_(3),and(C_(4)H_(9)NH_(3))_(2)Pb Br_(4) perovskites.By employing a simplified two-energy-level model analysis,our results indicate that these large MPA coefficients are primarily determined by the remarkable absorption cross sections,which are approximately 4.82×10^(-52)·cm^(4)·s·photon^(-1)at 620 nm for 2PAand 8.17×10^(-80)·cm^(6)·s^(2)·photon^(-2)at 1500 nm for 3PA.Our findings demonstrate significant potential for utilizing Ga S films in nonlinear optical applications.
文摘In this paper, we put emphasis on the analysis the mechanism of the photon induced frequency conversion β BaB 2O 4 crystal inside a borate glass using femtosecond laser. Because of the nature of femtosecond laser's ultra short pulse duration and high energy density, in essence the laser glass interaction mechanism is changed. Based on multiphoton ionization, collisional ionization and the network depolymerization in the borate glass, production of the plasma drives the microstructure rearrangement near the laser beam focusing area. From the structure of glass and crystal analysis, we conclude that the complicated borate groups containing BO 3 and BO 4 units inside the glass are converted into(B 3O 6) -3 anion rings.
基金financially supported by the National Natural Science Foundation of China(Grant numbers 52275429 and 62205117)。
文摘ZnO nanomaterials have become appealing for next-generation micro/nanodevices owing to their remarkable functionality and outstanding performance.However,in-situ,one-step,patterned synthesis of ZnO nanomaterials with small grain sizes and high specific surface areas remains challenging.While breakthroughs in laser-based synthesis techniques have enabled simultaneous growth and patterning of these materials,device integration restrictions owing to pre-prepared laser-absorbing layers remain a severe issue.Herein,we report a single-step femtosecond laser direct writing(FsLDW)method for fabricating ZnO nanomaterial micropatterns with a minimum linewidth of less than 1μm without requiring laser-absorbing layers.Furthermore,utilizing the grain-size modulation effect of glycerol,we successfully reduced the grain size and addressed the challenges of discontinuity and non-uniform product formation during FsLDW.Using this technique,we successfully fabricated a series of 2 micro-photodetectors with exceptional performance,a switching ratio of 105,and a responsivity of 10 A/W.Notably,the devices exhibited an ultralow dark current of less than 10 pA,more than one order of magnitude lower than the dark current of ZnO photodetectors under the same bias voltage—crucial for enhancing the signal-to-noise ratio and reducing the power consumption of photodetectors.The proposed method could be extended to preparing other metal-oxide nanomaterials and devices,thus providing new opportunities for developing customized,miniaturized,and integrated functional devices.
