Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, includin...Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.展开更多
Electron–phonon coupling can tailor electronic transition processes and result in direct lasing far beyond the fluorescence spectrum.The applicable time scales of these kinds of multiphonon-assisted lasers determine ...Electron–phonon coupling can tailor electronic transition processes and result in direct lasing far beyond the fluorescence spectrum.The applicable time scales of these kinds of multiphonon-assisted lasers determine their scientific boundaries and further developments,since the response speed of lattice vibrations is much slower than that of electrons.At present,the temporal dynamic behavior of multiphononassisted lasers has not yet been explored.Herein,we investigate the Q-switched laser performance of ytterbium-doped YCa_(4)OðBO_(3)Þ_(3)(Yb:YCOB)crystal with phonon-assisted emission in nanosecond scales.Using different Q-switchers,the three-phonon-assisted lasers around 1130 nm were realized,and a stable Q-switching was realized in the time domain from submicroseconds to tens of nanoseconds.To the best of our knowledge,this is the longest laser wavelength in all pulse Yb lasers.The minimum pulse width and maximum pulse energy are 29 ns and 204μJ,respectively.These results identify that the electron–phonon coupling is a fast physical process,at least much faster than the present nanosecond pulse width,which supports the operation of multiphonon-assisted lasers in the nanosecond range.In addition,we also provide a simple setup to create pulse lasers at those wavelengths with weak spontaneous emission.Keywords:pulse lasers;electron–phonon coupling;nanoseconds;Q-switch.展开更多
Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required...Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport,which determines superior photoresponse and high stability.Herein,a general thermal-pressed(TP)strategy is designed to solve the above issues,achieving uniaxial orientation and single-grain penetration along the film thickness direction.It constructs the efficient channel for ordered carrier transport between two electrodes.Combining of the improved crystal quality and lower trap-state density,the quasi-2D and 3D perovskite-based self-powered photodetector devices(with/without hole transport layer)all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser.For the MAPbI_(3)-based self-powered photodetectors,the largest R_(λ) value is as high as 0.57 A W^(−1)at 760 nm,which is larger than most reported results.Meanwhile,under laser illumination(532 nm),the FPEA_(2)MA_(4)Pb_(5)I_(16)-based device exhibits a high responsivity(0.4 A W^(−1)) value,which is one of the best results in 2DRP self-powered photodetectors.In addition,fast response,ultralow detection limit,and markedly improved humidity,optical and heat stabilities are clearly demonstrated for these TP-based devices.展开更多
The sintering trajectory of the Ho,Pr:Y_(2)O_(3) ceramics could be effectively adjusted by sintering in a flowing oxygen atmosphere instead of vacuum.The final-stage grain growth was significantly suppressed by the us...The sintering trajectory of the Ho,Pr:Y_(2)O_(3) ceramics could be effectively adjusted by sintering in a flowing oxygen atmosphere instead of vacuum.The final-stage grain growth was significantly suppressed by the use of oxygen atmosphere presintering,resulting in smaller average grain sizes than those of samples sintered under vacuum,while the same relative density was achieved.After hot isostatic pressing(HIP),the oxygen presintered Ho,Pr:Y_(2)O_(3) ceramics achieved excellent optical quality,with transmittance exceeding 80%at a wavelength of 680 nm.The codoping of Pr^(3+) as deactivating ions effectively depopulated the lower energy level 5I7 during the Ho^(3+):^(5)I_(6)→^(5)I_(7) transition,thereby making the Ho,Pr:Y_(2)O_(3) ceramics more conducive to promoting population inversion in the 2.9μm laser wavelength range.展开更多
Zinc sulfide(ZnS)has promising linear and nonlinear optical properties and has shown important applications in military and modern devices.In this work,coupled with the chemical vapor deposition(CVD)method and hot iso...Zinc sulfide(ZnS)has promising linear and nonlinear optical properties and has shown important applications in military and modern devices.In this work,coupled with the chemical vapor deposition(CVD)method and hot isostatic pressing(HIP),we successfully grew a high-transmittance and low-absorption-coefficient polycrystalline ZnS with a size of 1 m×2 m and a thickness of 20 mm.The linear optical properties,including the UV-vis-NIR transmission spectrum,infrared spectrum,and refractive index,were systematically characterized,which shows that the present ZnS polycrystal exhibits a wide transmission range from 0.34 to 15.00μm,covering two important atmospheric windows.Moreover,its Sellmeier equation was achieved and fitted as a modification of previous studies.According to the refractive index and transmission spectrum,optical loss was calculated to be<3.5%from 1 to 10μm.All the results indicate that the present sample has comparable properties with the single crystals and should have potential applications as a functional material.展开更多
High-power diode-pumped solid-state lasers(DPSSLs)can support many important applications owing to their simple setup and high efficiency.However,the thermal effect in the laser crystal is a major limiting factor for ...High-power diode-pumped solid-state lasers(DPSSLs)can support many important applications owing to their simple setup and high efficiency.However,the thermal effect in the laser crystal is a major limiting factor for laser power improvement.Here,we originally present a quasi-continuous-wave(QCW)diode-pumped monolithic Yb^(3+)-doped YCa_(4)O(BO_(3))_(3)(Yb:YCOB)laser and realize the power scaling at room temperature by removing the heat efficiently.The Yb:YCOB laser at 1024 nm is designed with a quantum efficiency of 95%.A high-power QCW laser is realized with an output peak power of up to 226.7 W,a pulse energy of 12.2 m J,and an optical-to-optical efficiency of 41.2%.To the best of our knowledge,this result represents the record peak power in Yb:YCOB lasers and should have promising applications in some modern devices requiring high-power and large-energy lasers.展开更多
For the first time,to our knowledge,the cascading effects of self-phase modulation and second-harmonic generation(SPMSHG)in a nonlinear optical medium were used to conveniently convert a near-infrared ultrafast laser ...For the first time,to our knowledge,the cascading effects of self-phase modulation and second-harmonic generation(SPMSHG)in a nonlinear optical medium were used to conveniently convert a near-infrared ultrafast laser with a fixed center wavelength into a visible to deep-ultraviolet(DUV)laser with a continuously tunable wavelength.When aβ-BaB_(2)O_(4)(BBO)crystal was used as the nonlinear optical medium,and a Ti:sapphire laser(800 nm,38 fs)was used as the fundamental light source,the output wavelength had a tunable range of 225-460 nm,and the highest optical conversion efficiency reached 18.1%at 361 nm.For a 1030 nm fundamental light source,the shortest output wavelength was also 225 nm by one-step frequency conversion of the BBO crystal.By further frequency conversions,the tunable wavelength can extend to the vacuum ultraviolet(VUV)waveband,as short as 193 nm.These results demonstrated that SPM-SHG could be used as an extremely simple and effective frequency conversion method to obtain a wideband tunable ultraviolet laser.展开更多
Nonlinear Cherenkov radiation is a phenomenon of light first observed in 1970 that can be manipulated by phase matching conditions.However,under a rotatory symmetry,the nonlinear Cherenkov radiation was still untouche...Nonlinear Cherenkov radiation is a phenomenon of light first observed in 1970 that can be manipulated by phase matching conditions.However,under a rotatory symmetry,the nonlinear Cherenkov radiation was still untouched,where the rotation parameters in optics would introduce an additional phase to the beam,change the phase velocity of the electromagnetic wave,and lead to novel optical phenomena.Here,we introduce rotation as a new freedom and study the nonlinear Cherenkov radiation in optically rotatory crystals in theory.With a quartz crystal as the representative,we derive theoretical variations,which show that the phase velocity of the crystal-coupled wave is found to be accelerated or decelerated by the rotational angular velocity,corresponding to the change of the Cherenkov radiation angle.In addition,the variation on the effective nonlinear coefficient of quartz crystals with rotational polarization direction is analyzed theoretically and used to simulate the Cherenkov ring distribution in rotatory nonlinear optics.This work introduces the rotation parameter into the non-collinear phase matching process and may inspire the development of modern photonics and physics in rotatory frames.展开更多
Nonlinear frequency conversion is a ubiquitous technique that is used to obtain broad-range lasers and supercontinuum coherent sources.The phase-matching condition(momentum conservation relation)is the key criterion b...Nonlinear frequency conversion is a ubiquitous technique that is used to obtain broad-range lasers and supercontinuum coherent sources.The phase-matching condition(momentum conservation relation)is the key criterion but a challenging bottleneck in highly efficient conversion.Birefringent phase matching(BPM)and quasiphase matching(QPM)are two feasible routes but are strongly limited in natural anisotropic crystals or ferroelectric crystals.Therefore,it is in urgent demand for a general technique that can compensate for the phase mismatching in universal nonlinear materials and in broad wavelength ranges.Here,an additional periodic phase(APP)from order/disorder alignment is proposed to meet the phase-matching condition in arbitrary nonlinear crystals and demonstrated from the visible region to the deep-ultraviolet region(e.g.,LiNbO_(3) and quartz).Remarkably,pioneering 177.3-nm coherent output is first obtained in commercial quartz crystal with an unprecedented conversion efficiency above 1‰.This study not only opens a new roadmap to resuscitate those long-neglected nonlinear optical crystals for wavelength extension,but also may revolutionize next-generation nonlinear photonics and their further applications.展开更多
Praseodymium-ion-doped gain materials have the superiority of lasing at various visible wavelengths directly.Simple and compact visible lasers are booming with the development of blue laser diodes in recent years.In t...Praseodymium-ion-doped gain materials have the superiority of lasing at various visible wavelengths directly.Simple and compact visible lasers are booming with the development of blue laser diodes in recent years.In this Letter, we demonstrate the watt-level red laser with a single blue laser diode and Pr:YLiF4 crystal.On this basis,the passively Q-switched pulse lasers are obtained with monolayer graphene and Co:ZnO thin film as the Q-switchers in the visible range.展开更多
Manipulation of the light phase lies at the heart of the investigation of light-matter interactions,especially for efficient nonlinear optical processes.Here,we originally propose the angular engineering strategy of t...Manipulation of the light phase lies at the heart of the investigation of light-matter interactions,especially for efficient nonlinear optical processes.Here,we originally propose the angular engineering strategy of the additional periodic phase(APP)for realization of tunable phase matching and experimentally demonstrate the widely tunable phasematched second harmonic generation(SHG)which is expected for dozens of years.With an APP quartz crystal,the phase difference between the fundamental and frequency-doubled light is continuously angularly compensated under this strategy,which results the unprecedented and efficient frequency doubling at wavelengths almost covering the deep-UV spectral range from 221 to 332 nm.What’s more,all the possible phase-matching types are originally realized simultaneously under the angular engineering phase-matching conditions.This work should not only provide a novel and practical nonlinear photonic device for tunable deep-UV radiation but also be helpful for further study of the light-matter interaction process.展开更多
Since quasi-phase-matching of nonlinear optics was proposed in 1962,nonlinear photonic crystals were rapidly developed by ferroelectric domain inversion induced by electric or light poling.The three-dimensional(3D)per...Since quasi-phase-matching of nonlinear optics was proposed in 1962,nonlinear photonic crystals were rapidly developed by ferroelectric domain inversion induced by electric or light poling.The three-dimensional(3D)periodical rotation of ferroelectric domains may add feasible modulation to the nonlinear coefficients and break the rigid requirements for the incident light and polarization direction in traditional quasi-phase-matching media.However,3D rotating ferroelectric domains are difficult to fabricate by the direct external poling technique.Here,we show a natural potassium-tantalate-niobate(KTN)perovskite nonlinear photonic crystal with spontaneous Rubik’s cube-like domain structures near the Curie temperature of 40℃.The KTN crystal contains 3D ferroelectric polarization distributions corresponding to the reconfigured second-order susceptibilities,which can provide rich reciprocal vectors to compensate for the phase mismatch along an arbitrary direction and polarization of incident light.Bragg diffraction and broadband second-harmonic generation are also presented.This natural nonlinear photonic crystal directly meets the 3D quasi-phase-matching condition without external poling and establishes a promising platform for all-optical nonlinear beam shaping and enables new optoelectronic applications for perovskite ferroelectrics.展开更多
High-harmonic generation in the ultraviolet region is promising for wireless technology used for communications and sensing. However, small high-order nonlinear coefficients prevent us from obtaining high conversion e...High-harmonic generation in the ultraviolet region is promising for wireless technology used for communications and sensing. However, small high-order nonlinear coefficients prevent us from obtaining high conversion efficiency and functional photonic devices. Here, we show highly efficient ultraviolet harmonic generation extending to the fifth order directly from an epsilon-near-zero indium tin oxide(ITO) film. The real part of the annealed ITO films was designed to reach zero around 1050 nm, matching with the central wavelength of an Yb-based fiber laser, and the internal driving electric field was extremely enhanced. A high energy conversion efficiency of 10-4 and 10-6 for 257.5 nm(fourth-order) and 206 nm(fifth-order) ultraviolet harmonic generation was obtained,which is at least 2 orders of magnitude higher than early reports. Our results demonstrate a new route for overcoming the inefficiency problem and open up the possibilities of compact solid-state high-harmonic generation sources at nanoscale.展开更多
In this work,we demonstrate the phonon-assisted vibronic lasing of a Yb-doped sesquioxide Yb:LuScO_(3)crystal.The electron–phonon coupling process was analyzed and the Huang-Rhys factor S was calculated to be 0.75 as...In this work,we demonstrate the phonon-assisted vibronic lasing of a Yb-doped sesquioxide Yb:LuScO_(3)crystal.The electron–phonon coupling process was analyzed and the Huang-Rhys factor S was calculated to be 0.75 associated with the fluorescence spectrum at room temperature.By a rational cavity design to suppress lasing below 1100 nm,a continuously spectral tunability from 1121 to 1136 nm was realized in a Yb:LuScO_(3)laser,which represents the longest achievable wavelength in the Yb-doped sesquioxide lasers.Moreover,the Raman spectrum indicated that the Egphonon mode with a frequency of 472 cm^(-1)was mainly devoted to the phonon-assisted transition process.This work broadens the achievable laser spectrum of Yb-doped sesquioxide,and suggests that the multiphonon–electron coupling strategy should be universal for other laser materials.展开更多
MoS2 is considered as an ideal electrode material in the field of energy storage due to high theoretical specific capacity and unique layered structure.However,limited interlayer distance and poor intrinsic electrical...MoS2 is considered as an ideal electrode material in the field of energy storage due to high theoretical specific capacity and unique layered structure.However,limited interlayer distance and poor intrinsic electrical conductivity restrict its potential realworld application.Herein,an alternately intercalated structure of MoS2 monolayer and N-doped porous carbon(NC)layer is grown on reduced graphene oxide(rGO)via a chemical intercalated strategy.The expanded interlayer distance of MoS2(0.96 nm),enlarged by the intercalation of N-doped porous carbon layers,can enhance ion diffusion mobility,provide additional reactive sites for ion storage and maintain the stability of electrode structure.In addition,the hierarchical structures between rGO substrate and intercalated N-doped carbon layers construct a three-dimensional(3D)conductive network,which can significantly improve the electrical conductivity and the structural stability.As a result,the rGO-supported MoS2/NC electrode exhibits an ultrahigh reversible capacity and remarkable long cycling stability for sodium-ion batteries(SIBs)and potassium-ion(PIBs).Meanwhile,the as-obtained MoS2/NC@rGO electrode also delivers a superior cycle performance of 250 mAh·g−1 after 160 cycles at 0.5 A·g−1 when employed as an anode for sodium-ion full cells.展开更多
VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer s...VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer spacing(0.57 nm)of VS2 generally determines high ion diffusion barrier and large volume variation,resulting in unsatisfactory electrochemical performance of SIBs and PIBs.In this work,flower-like VS_(2)/N-doped carbon(VS_(2)/N-C)with expanded(001)plane is grown on reduced graphene oxide(rGO)via a solvothermal and subsequently carbonization strategy.In the VS_(2)/N-C@rGO nanohybrids,the ultrathin VS2"petals"are alternately intercalated by the N-doped porous carbon monolayers to achieve an expanded interlayer spacing(1.02 nm),which can effectively reduce ions diffusion barrier,expose abundant active sites for Na+/K+intercalation,and tolerate large volume variation.The N-C and rGO carbonous materials can significantly promote the electrical conductivity and structural stability.Benefited from the synergistic effect,the VS2/N-C@rGO electrode exhibits large reversible capacity(Na+:407 mAh·g^(-1) at 1 A·g^(-1);K^(+):334 mAh·g^(-1) at 0.2 A·g^(-1)),high rate capacity(Na+:273 mAh·g^(-1) at 8 A·g^(-1);K+:186 mAh·g^(-1) at 5 A·g^(-1)),and remarkable cycling stability(Na+:316 mAh·g^(-1) at 2 A·g^(-1) after 1,400 cycles;K^(+):216 mAh·g^(-1) at 1 A·g^(-1) after 500 cycles).展开更多
Since the first invention of the laser in 1960,direct lasing outside the fluorescence spectrum is deemed impossible owing to the“zero-gain”cross-section.However,when electron-phonon coupling meets laser oscillation,...Since the first invention of the laser in 1960,direct lasing outside the fluorescence spectrum is deemed impossible owing to the“zero-gain”cross-section.However,when electron-phonon coupling meets laser oscillation,an energy modulation by the quantized phonon can tailor the electronic transitions,thus directly creating some unprecedented lasers with extended wavelengths by phonon engineering.Here,we demonstrate a broadband lasing(1000-1280 nm)in a Yb-doped La_(2)CaB_(10)O_(19)(Yb:LCB)crystal,far beyond its spontaneous fluorescence spectrum.Numerical calculations and in situ Raman verify that such a substantial laser emission is devoted to the multiphonon coupling to lattice vibrations of a dangling“quasi-free-oxygen”site,with the increasing phonon numbers step-by-step(n=1–6).This new structural motif provides more alternative candidates with strong-coupling laser materials.Moreover,the quantitative relations between phonon density distribution and laser wavelength extension are discussed.These results give rise to the search for on-demand lasers in the darkness and pave a reliable guideline to study those intriguing electron-phonon-photon coupled systems for integrated photonic applications.展开更多
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
文摘Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA0717800 and 2021YFB3601504)the National Natural Science Foundation of China(Grant Nos.52025021,51890863,and 52002220)the Future Plans of Young Scholars at Shandong University。
文摘Electron–phonon coupling can tailor electronic transition processes and result in direct lasing far beyond the fluorescence spectrum.The applicable time scales of these kinds of multiphonon-assisted lasers determine their scientific boundaries and further developments,since the response speed of lattice vibrations is much slower than that of electrons.At present,the temporal dynamic behavior of multiphononassisted lasers has not yet been explored.Herein,we investigate the Q-switched laser performance of ytterbium-doped YCa_(4)OðBO_(3)Þ_(3)(Yb:YCOB)crystal with phonon-assisted emission in nanosecond scales.Using different Q-switchers,the three-phonon-assisted lasers around 1130 nm were realized,and a stable Q-switching was realized in the time domain from submicroseconds to tens of nanoseconds.To the best of our knowledge,this is the longest laser wavelength in all pulse Yb lasers.The minimum pulse width and maximum pulse energy are 29 ns and 204μJ,respectively.These results identify that the electron–phonon coupling is a fast physical process,at least much faster than the present nanosecond pulse width,which supports the operation of multiphonon-assisted lasers in the nanosecond range.In addition,we also provide a simple setup to create pulse lasers at those wavelengths with weak spontaneous emission.Keywords:pulse lasers;electron–phonon coupling;nanoseconds;Q-switch.
基金the National Natural Science Foundation of China(NSFC,No.51872172,51972197)Natural Science Foundation of Shandong Province(ZR2019MEM021)Young Scholars Program of Shandong University.
文摘Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport,which determines superior photoresponse and high stability.Herein,a general thermal-pressed(TP)strategy is designed to solve the above issues,achieving uniaxial orientation and single-grain penetration along the film thickness direction.It constructs the efficient channel for ordered carrier transport between two electrodes.Combining of the improved crystal quality and lower trap-state density,the quasi-2D and 3D perovskite-based self-powered photodetector devices(with/without hole transport layer)all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser.For the MAPbI_(3)-based self-powered photodetectors,the largest R_(λ) value is as high as 0.57 A W^(−1)at 760 nm,which is larger than most reported results.Meanwhile,under laser illumination(532 nm),the FPEA_(2)MA_(4)Pb_(5)I_(16)-based device exhibits a high responsivity(0.4 A W^(−1)) value,which is one of the best results in 2DRP self-powered photodetectors.In addition,fast response,ultralow detection limit,and markedly improved humidity,optical and heat stabilities are clearly demonstrated for these TP-based devices.
基金supported by the National Key R&D Program of China(No.2022YFB3605800)the National Natural Science Foundation of China(Nos.62105130,62075089,52372010,52422201,11654005,and 12234014)+4 种基金the Natural Science Foundation of Shandong Province(No.ZR2023ZD53)the Research Capability Elevation Program of Guangdong Province(No.2022ZDJS116)the National Science Foundation of Top Talent of SZTU(No.GDRC202302)the Innovation Program for Quantum Science and Technology(No.2021ZD0303200)the Shanghai Municipal Science and Technology Major Project(Nos.2019SHZDZX01,22DZ2229004).
文摘The sintering trajectory of the Ho,Pr:Y_(2)O_(3) ceramics could be effectively adjusted by sintering in a flowing oxygen atmosphere instead of vacuum.The final-stage grain growth was significantly suppressed by the use of oxygen atmosphere presintering,resulting in smaller average grain sizes than those of samples sintered under vacuum,while the same relative density was achieved.After hot isostatic pressing(HIP),the oxygen presintered Ho,Pr:Y_(2)O_(3) ceramics achieved excellent optical quality,with transmittance exceeding 80%at a wavelength of 680 nm.The codoping of Pr^(3+) as deactivating ions effectively depopulated the lower energy level 5I7 during the Ho^(3+):^(5)I_(6)→^(5)I_(7) transition,thereby making the Ho,Pr:Y_(2)O_(3) ceramics more conducive to promoting population inversion in the 2.9μm laser wavelength range.
基金supported by the National Natural Science Foundation of China(Nos.52025021,52372009,and 52272004)the Qilu Young Scholar Program of Shandong University。
文摘Zinc sulfide(ZnS)has promising linear and nonlinear optical properties and has shown important applications in military and modern devices.In this work,coupled with the chemical vapor deposition(CVD)method and hot isostatic pressing(HIP),we successfully grew a high-transmittance and low-absorption-coefficient polycrystalline ZnS with a size of 1 m×2 m and a thickness of 20 mm.The linear optical properties,including the UV-vis-NIR transmission spectrum,infrared spectrum,and refractive index,were systematically characterized,which shows that the present ZnS polycrystal exhibits a wide transmission range from 0.34 to 15.00μm,covering two important atmospheric windows.Moreover,its Sellmeier equation was achieved and fitted as a modification of previous studies.According to the refractive index and transmission spectrum,optical loss was calculated to be<3.5%from 1 to 10μm.All the results indicate that the present sample has comparable properties with the single crystals and should have potential applications as a functional material.
基金supported by the National Key Research and Development Program of China(Nos.2021YFA0717800,2021YFB3601504,and 2023YFF0718801)the National Natural Science Foundation of China(Nos.52025021,52422201,52372010,and U23A20558)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2023ZD53)the Future Plans of Young Scholars at Shandong University。
文摘High-power diode-pumped solid-state lasers(DPSSLs)can support many important applications owing to their simple setup and high efficiency.However,the thermal effect in the laser crystal is a major limiting factor for laser power improvement.Here,we originally present a quasi-continuous-wave(QCW)diode-pumped monolithic Yb^(3+)-doped YCa_(4)O(BO_(3))_(3)(Yb:YCOB)laser and realize the power scaling at room temperature by removing the heat efficiently.The Yb:YCOB laser at 1024 nm is designed with a quantum efficiency of 95%.A high-power QCW laser is realized with an output peak power of up to 226.7 W,a pulse energy of 12.2 m J,and an optical-to-optical efficiency of 41.2%.To the best of our knowledge,this result represents the record peak power in Yb:YCOB lasers and should have promising applications in some modern devices requiring high-power and large-energy lasers.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2023ZD02)the Key Research and Development Program of Shandong Province(No.2022CXGC010104)the Young Foundation of Shandong Province(No.ZR2024QF224)。
文摘For the first time,to our knowledge,the cascading effects of self-phase modulation and second-harmonic generation(SPMSHG)in a nonlinear optical medium were used to conveniently convert a near-infrared ultrafast laser with a fixed center wavelength into a visible to deep-ultraviolet(DUV)laser with a continuously tunable wavelength.When aβ-BaB_(2)O_(4)(BBO)crystal was used as the nonlinear optical medium,and a Ti:sapphire laser(800 nm,38 fs)was used as the fundamental light source,the output wavelength had a tunable range of 225-460 nm,and the highest optical conversion efficiency reached 18.1%at 361 nm.For a 1030 nm fundamental light source,the shortest output wavelength was also 225 nm by one-step frequency conversion of the BBO crystal.By further frequency conversions,the tunable wavelength can extend to the vacuum ultraviolet(VUV)waveband,as short as 193 nm.These results demonstrated that SPM-SHG could be used as an extremely simple and effective frequency conversion method to obtain a wideband tunable ultraviolet laser.
基金supported by the National Natural Science Foundation of China(Nos.52025021 and 92163207)the National Key Research and Development Program of China(Nos.2023YFF0718900 and 2021YFA0717800)。
文摘Nonlinear Cherenkov radiation is a phenomenon of light first observed in 1970 that can be manipulated by phase matching conditions.However,under a rotatory symmetry,the nonlinear Cherenkov radiation was still untouched,where the rotation parameters in optics would introduce an additional phase to the beam,change the phase velocity of the electromagnetic wave,and lead to novel optical phenomena.Here,we introduce rotation as a new freedom and study the nonlinear Cherenkov radiation in optically rotatory crystals in theory.With a quartz crystal as the representative,we derive theoretical variations,which show that the phase velocity of the crystal-coupled wave is found to be accelerated or decelerated by the rotational angular velocity,corresponding to the change of the Cherenkov radiation angle.In addition,the variation on the effective nonlinear coefficient of quartz crystals with rotational polarization direction is analyzed theoretically and used to simulate the Cherenkov ring distribution in rotatory nonlinear optics.This work introduces the rotation parameter into the non-collinear phase matching process and may inspire the development of modern photonics and physics in rotatory frames.
基金financially supported by the National Natural Science Foundation of China(51890863,51772173,and 51632004)the National Key Research and Development Program of China(Grant Nos.2016YFB0701002 and 2016YFB1102301)the Provincial Key Research and Development Program of Shandong(Grant No.2017CXGC0414).
文摘Nonlinear frequency conversion is a ubiquitous technique that is used to obtain broad-range lasers and supercontinuum coherent sources.The phase-matching condition(momentum conservation relation)is the key criterion but a challenging bottleneck in highly efficient conversion.Birefringent phase matching(BPM)and quasiphase matching(QPM)are two feasible routes but are strongly limited in natural anisotropic crystals or ferroelectric crystals.Therefore,it is in urgent demand for a general technique that can compensate for the phase mismatching in universal nonlinear materials and in broad wavelength ranges.Here,an additional periodic phase(APP)from order/disorder alignment is proposed to meet the phase-matching condition in arbitrary nonlinear crystals and demonstrated from the visible region to the deep-ultraviolet region(e.g.,LiNbO_(3) and quartz).Remarkably,pioneering 177.3-nm coherent output is first obtained in commercial quartz crystal with an unprecedented conversion efficiency above 1‰.This study not only opens a new roadmap to resuscitate those long-neglected nonlinear optical crystals for wavelength extension,but also may revolutionize next-generation nonlinear photonics and their further applications.
基金supported by the National Key Research and Development Program of China(Nos.2016YFB0701002and 2016YFB1102301)the National Natural Science Foundation of China(NSFC)(Nos.51772173,51632004,51472257,and 51872307)
文摘Praseodymium-ion-doped gain materials have the superiority of lasing at various visible wavelengths directly.Simple and compact visible lasers are booming with the development of blue laser diodes in recent years.In this Letter, we demonstrate the watt-level red laser with a single blue laser diode and Pr:YLiF4 crystal.On this basis,the passively Q-switched pulse lasers are obtained with monolayer graphene and Co:ZnO thin film as the Q-switchers in the visible range.
基金This work was financially supported by the National Natural Science Foundation of China(NSFC)(92163207,52025021,51890863)Future Plans of Young Scholars at Shandong University.
文摘Manipulation of the light phase lies at the heart of the investigation of light-matter interactions,especially for efficient nonlinear optical processes.Here,we originally propose the angular engineering strategy of the additional periodic phase(APP)for realization of tunable phase matching and experimentally demonstrate the widely tunable phasematched second harmonic generation(SHG)which is expected for dozens of years.With an APP quartz crystal,the phase difference between the fundamental and frequency-doubled light is continuously angularly compensated under this strategy,which results the unprecedented and efficient frequency doubling at wavelengths almost covering the deep-UV spectral range from 221 to 332 nm.What’s more,all the possible phase-matching types are originally realized simultaneously under the angular engineering phase-matching conditions.This work should not only provide a novel and practical nonlinear photonic device for tunable deep-UV radiation but also be helpful for further study of the light-matter interaction process.
基金The National Natural Science Foundation of China(NSFC)(51632004,51672164,51772173,51890863,and 52002220)National Key Research and Development Program of China(2016YFB0701002 and 2016YFB1102301)+1 种基金Taishan Scholar Foundation of Shandong Province,Chinathe support from Future Plans of Young Scholars at Shandong University.
文摘Since quasi-phase-matching of nonlinear optics was proposed in 1962,nonlinear photonic crystals were rapidly developed by ferroelectric domain inversion induced by electric or light poling.The three-dimensional(3D)periodical rotation of ferroelectric domains may add feasible modulation to the nonlinear coefficients and break the rigid requirements for the incident light and polarization direction in traditional quasi-phase-matching media.However,3D rotating ferroelectric domains are difficult to fabricate by the direct external poling technique.Here,we show a natural potassium-tantalate-niobate(KTN)perovskite nonlinear photonic crystal with spontaneous Rubik’s cube-like domain structures near the Curie temperature of 40℃.The KTN crystal contains 3D ferroelectric polarization distributions corresponding to the reconfigured second-order susceptibilities,which can provide rich reciprocal vectors to compensate for the phase mismatch along an arbitrary direction and polarization of incident light.Bragg diffraction and broadband second-harmonic generation are also presented.This natural nonlinear photonic crystal directly meets the 3D quasi-phase-matching condition without external poling and establishes a promising platform for all-optical nonlinear beam shaping and enables new optoelectronic applications for perovskite ferroelectrics.
基金National Natural Science Foundation of China(51632004, 51772173, 51890863, 51902181, 52002220)Taishan Scholar Foundation of Shandong ProvinceFuture Plans of Young Scholars at Shandong University。
文摘High-harmonic generation in the ultraviolet region is promising for wireless technology used for communications and sensing. However, small high-order nonlinear coefficients prevent us from obtaining high conversion efficiency and functional photonic devices. Here, we show highly efficient ultraviolet harmonic generation extending to the fifth order directly from an epsilon-near-zero indium tin oxide(ITO) film. The real part of the annealed ITO films was designed to reach zero around 1050 nm, matching with the central wavelength of an Yb-based fiber laser, and the internal driving electric field was extremely enhanced. A high energy conversion efficiency of 10-4 and 10-6 for 257.5 nm(fourth-order) and 206 nm(fifth-order) ultraviolet harmonic generation was obtained,which is at least 2 orders of magnitude higher than early reports. Our results demonstrate a new route for overcoming the inefficiency problem and open up the possibilities of compact solid-state high-harmonic generation sources at nanoscale.
基金supported by the National Key Research and Development Program of China(Nos.2021YFB3601504 and 2021YFA0717800)the National Natural Science Foundation of China(Nos.52002220,92163207,52025021,and 51890863)the Future Plans of Young Scholars at Shandong University。
文摘In this work,we demonstrate the phonon-assisted vibronic lasing of a Yb-doped sesquioxide Yb:LuScO_(3)crystal.The electron–phonon coupling process was analyzed and the Huang-Rhys factor S was calculated to be 0.75 associated with the fluorescence spectrum at room temperature.By a rational cavity design to suppress lasing below 1100 nm,a continuously spectral tunability from 1121 to 1136 nm was realized in a Yb:LuScO_(3)laser,which represents the longest achievable wavelength in the Yb-doped sesquioxide lasers.Moreover,the Raman spectrum indicated that the Egphonon mode with a frequency of 472 cm^(-1)was mainly devoted to the phonon-assisted transition process.This work broadens the achievable laser spectrum of Yb-doped sesquioxide,and suggests that the multiphonon–electron coupling strategy should be universal for other laser materials.
基金The authors are grateful to the National Key Research and Development Project(No.51890863)the National Natural Science Foundation of China(Nos.51872172 and 51972197)+1 种基金Natural Science Foundation of Shandong Province(Nos.ZR2019MEM021 and ZR2020QE067)Young Scholars Program of Shandong University.
文摘MoS2 is considered as an ideal electrode material in the field of energy storage due to high theoretical specific capacity and unique layered structure.However,limited interlayer distance and poor intrinsic electrical conductivity restrict its potential realworld application.Herein,an alternately intercalated structure of MoS2 monolayer and N-doped porous carbon(NC)layer is grown on reduced graphene oxide(rGO)via a chemical intercalated strategy.The expanded interlayer distance of MoS2(0.96 nm),enlarged by the intercalation of N-doped porous carbon layers,can enhance ion diffusion mobility,provide additional reactive sites for ion storage and maintain the stability of electrode structure.In addition,the hierarchical structures between rGO substrate and intercalated N-doped carbon layers construct a three-dimensional(3D)conductive network,which can significantly improve the electrical conductivity and the structural stability.As a result,the rGO-supported MoS2/NC electrode exhibits an ultrahigh reversible capacity and remarkable long cycling stability for sodium-ion batteries(SIBs)and potassium-ion(PIBs).Meanwhile,the as-obtained MoS2/NC@rGO electrode also delivers a superior cycle performance of 250 mAh·g−1 after 160 cycles at 0.5 A·g−1 when employed as an anode for sodium-ion full cells.
基金The authors are grateful to the National Key Research and Development Project(No.51890863)the National Natural Science Foundation of China(NSFC,Nos.51872172 and 51972197)+2 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2018MEM010 and ZR2019MEM021)Major Research and Development Program for Public Welfare in Shandong(No.2018GGX102021)Young Scholars Program of Shandong University.
文摘VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer spacing(0.57 nm)of VS2 generally determines high ion diffusion barrier and large volume variation,resulting in unsatisfactory electrochemical performance of SIBs and PIBs.In this work,flower-like VS_(2)/N-doped carbon(VS_(2)/N-C)with expanded(001)plane is grown on reduced graphene oxide(rGO)via a solvothermal and subsequently carbonization strategy.In the VS_(2)/N-C@rGO nanohybrids,the ultrathin VS2"petals"are alternately intercalated by the N-doped porous carbon monolayers to achieve an expanded interlayer spacing(1.02 nm),which can effectively reduce ions diffusion barrier,expose abundant active sites for Na+/K+intercalation,and tolerate large volume variation.The N-C and rGO carbonous materials can significantly promote the electrical conductivity and structural stability.Benefited from the synergistic effect,the VS2/N-C@rGO electrode exhibits large reversible capacity(Na+:407 mAh·g^(-1) at 1 A·g^(-1);K^(+):334 mAh·g^(-1) at 0.2 A·g^(-1)),high rate capacity(Na+:273 mAh·g^(-1) at 8 A·g^(-1);K+:186 mAh·g^(-1) at 5 A·g^(-1)),and remarkable cycling stability(Na+:316 mAh·g^(-1) at 2 A·g^(-1) after 1,400 cycles;K^(+):216 mAh·g^(-1) at 1 A·g^(-1) after 500 cycles).
基金supported by the National Key Research and Development Program of China(2021YFB3601504 and 2021YFA0717800)National Natural Science Foundation of China(52025021,92163207,51890862,51890863,and 52002220)Future Plans of Young Scholars at Shandong University.
文摘Since the first invention of the laser in 1960,direct lasing outside the fluorescence spectrum is deemed impossible owing to the“zero-gain”cross-section.However,when electron-phonon coupling meets laser oscillation,an energy modulation by the quantized phonon can tailor the electronic transitions,thus directly creating some unprecedented lasers with extended wavelengths by phonon engineering.Here,we demonstrate a broadband lasing(1000-1280 nm)in a Yb-doped La_(2)CaB_(10)O_(19)(Yb:LCB)crystal,far beyond its spontaneous fluorescence spectrum.Numerical calculations and in situ Raman verify that such a substantial laser emission is devoted to the multiphonon coupling to lattice vibrations of a dangling“quasi-free-oxygen”site,with the increasing phonon numbers step-by-step(n=1–6).This new structural motif provides more alternative candidates with strong-coupling laser materials.Moreover,the quantitative relations between phonon density distribution and laser wavelength extension are discussed.These results give rise to the search for on-demand lasers in the darkness and pave a reliable guideline to study those intriguing electron-phonon-photon coupled systems for integrated photonic applications.
