The output radiation from the 100μm×1μm aperture of a high power Laser Diode (LD) is efficiently coupled into a 50μm multimode optical fiber.The fiber output of the high power LD with high brightness and high ...The output radiation from the 100μm×1μm aperture of a high power Laser Diode (LD) is efficiently coupled into a 50μm multimode optical fiber.The fiber output of the high power LD with high brightness and high power density is achieved.The power density is up to 3 6×104W/cm2 and the coupling efficiency is 70%.The extreme divergence and the astigmatism of high power LDs require the optics with complex lens structures and high performance.A double-curved lens with two crossed cylindrical lenses structured on both sides of the glass substrate is used in the coupling system.展开更多
High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes （HWOLEDs） with the configuration of indium tin oxide （ITO）/ N, N, N, N-tetrakis（4-methoxyphenyl）-benzidine （MeO-TPD）：...High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes （HWOLEDs） with the configuration of indium tin oxide （ITO）/ N, N, N, N-tetrakis（4-methoxyphenyl）-benzidine （MeO-TPD）： tetrafluoro-tetracyanoqino dimethane （F4-TCNQ）/N,N-di（naphthalene-1-yl）-N,N-diphenyl-benzidine （NPB）/ 4,4-N,N-dicarbazolebiphenyl （CBP）： iridium （III） diazine complexes （MPPZ） 2 Ir（acac）/NPB/2-methyl-9,10-di（2-naphthyl）anthracene （MADN）： p-bis（p-N,N-di-phenyl-aminostyryl）benzene （DSA-ph）/bis（10-hydroxybenzo[h] quino-linato）beryllium complex （Bebq2）/LiF/Al have been fabricated and characterized. The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V, and the Commission Internationale de l’Eclairage （CIE） chromaticity coordinates are almost constant during a large voltage change of 6–12 V. Furthermore, a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained, which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2. We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/blue-fluorescence in the device. Undoubtedly, this is one of the most exciting results in two-wavelength HWOLEDs up to now.展开更多
A new compact XGA projection is designed with three 0.99" liquid crystal panels. By using 275W UHP lamp, above 3000 ANSI lumens could be achieved with the uniformity of 85%. The color temperature is 6742K.
It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report ...It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report a molecular engineering approach to afford NIR-Ⅱ fluorophores with these merits based on fused-ring acceptor(FRA)molecules.Dioctyl 3,4-propylenedioxy thiophene(PDOT-C8)is utilized as the bridging donor to replace 3-ethylhexyloxy thiophene(3-EHOT),leading to more than 20 times enhancement of brightness.The nanofluorophores(NFs)based on the optimized CPTIC-4F molecule exhibit an emission peak of 1,110 nm with a fluorescence quantum yield(QY)of 0.39%(QY of IR-26 is 0.050%in dichloroethane as reference)and peak absorption coefficient of 14.5 x 10^4 M^-1·cm^-1 in aqueous solutions,which are significantly higher than those of 3-EHOT based COTIC-4F NFs.It is found that PDOT-C8 can weaken intermolecular aggregation,enhance protection of molecular backbone from water,and decrease backbone distortion,beneficial for the high brightness.Compared with indocyanine green with same injection dose,CPTIC-4F NFs show 10 times higher signal-to-background ratio for whole body vessels imaging at 1,300 nm long pass filters.展开更多
We report a simple,effective,and universal lattice reconstruction approach to improve the quality of perovskite films by using nonpolar solvents with high Gutmann donor numbers(DNs).We find that high-DN nonpolar solve...We report a simple,effective,and universal lattice reconstruction approach to improve the quality of perovskite films by using nonpolar solvents with high Gutmann donor numbers(DNs).We find that high-DN nonpolar solvents,for instance,ethyl acetate,can interact with perovskite precursors.Such a solvent can make the perovskite lattice more ordered and“harder”and promote the formation of heterostructures with low-dimensional perovskite impurities and residual solvent molecules.As a result,the latticereconstructed perovskite films exhibit reduced defect densities and suppressed ion migration.The resultant mixed-halide blue perovskite light-emitting diodes(PeLEDs)show greatly enhanced tolerance to high driving current densities and voltages,demonstrating high brightness,outstanding color stability and low efficiency roll-off.Our work provides a deep understanding of the interactions between nonpolar solvents and perovskites and offers useful guidelines for further development of high-power PeLEDs.展开更多
The research of high-brightness organic light-emitting diodes, as an important branch of organic light-emitting diodes （OLEDs）, makes it possible for achieving high-brightness lighting source and lasing. Heat dissip...The research of high-brightness organic light-emitting diodes, as an important branch of organic light-emitting diodes （OLEDs）, makes it possible for achieving high-brightness lighting source and lasing. Heat dissipation and efficiency roll off, as two main factors, affect the brightness of the OLEDs heavily. In this paper, high-brightness OLEDs are obtained by utilizing pulse voltage, small areas and micro-cavity structure to minimize the effect of the two factors. The major advances, ongoing challenges and future perspectives of this research frontier are also critically discussed.展开更多
Inorganic luminescent materials have been widely used as color converters for applications in lighting and displays [1-6].In recent years, laser-driven solid-state lighting based on phosphor-converted white laser diod...Inorganic luminescent materials have been widely used as color converters for applications in lighting and displays [1-6].In recent years, laser-driven solid-state lighting based on phosphor-converted white laser diode (pc-WLD) technology, which is commonly fabricated with the combination of "blue LD+color converters", is rising for high-power lighting due to its super-high brightness, reliability and compactness [7,8].展开更多
Fiber-coupled laser pumps with low size,weight and power consumption(SWaP)have become more and more compelling for applications in both industrial and defense applications.This study presents an innovative approach em...Fiber-coupled laser pumps with low size,weight and power consumption(SWaP)have become more and more compelling for applications in both industrial and defense applications.This study presents an innovative approach employing the spectral beam combining technique and double-junction laser diode chips to create efficient,high-power,high-brightness fiber-coupled packages.We successfully demonstrated a wavelength-stabilized pump module capable of delivering over 560 W of ex-fiber power with an electro-optical conversion efficiency of 55%from a 135μm diameter,0.22 numerical aperture fiber.The specific mass and volume metrics achieved are 0.34 kg/kW and 0.23 cm^(3)/W,respectively.The module exhibits a stabilized spectrum with a 3.6 nm consistent interval of two spectral peaks and a 4.2 nm full width at half maximum across a wide range of operating currents.展开更多
The n type GaAs substrates are used and their conductive type is changed to p type by tunnel junction for AlGaInP light emitting diodes(TJ LED),then n type GaP layer is used as current spreading layer.Because resi...The n type GaAs substrates are used and their conductive type is changed to p type by tunnel junction for AlGaInP light emitting diodes(TJ LED),then n type GaP layer is used as current spreading layer.Because resistivity of the n type GaP is lower than that of p type,the effect of current spreading layer is enhanced and the light extraction efficiency is increased by the n type GaP current spreading layer.For TJ LED with 3μm n type GaP current spreading layer,experimental results show that compared with conventional LED with p type GaP current spreading layer,light output power is increased for 50% at 20mA and for 66 7% at 100mA.展开更多
A novel type of high power edge-emitting semiconductor laser （SL） with extended vertical photonic band crystal （PBC） waveguide was reviewed. Simulations predict narrow beam divergence, resulting from the thick PBC...A novel type of high power edge-emitting semiconductor laser （SL） with extended vertical photonic band crystal （PBC） waveguide was reviewed. Simulations predict narrow beam divergence, resulting from the thick PBC waveguide, to be independent of realistic variations of the growth parameters. Narrow ridge lasers fabricated along the simulations indeed demonstrate superior output power, narrow beam divergence, circular beam profile, excellent beam quality and very low astigmatism. Efficient fiber coupling decisive for most applications was thus eased. Stability of the laser under a wide range of operating temperature was demonstrated. Ultrashort pulses with few ps of duration at GHz repetition rates were generated by passively mode locking the lasers.展开更多
Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality...Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality of the laser diode is very poor, the 915 nm laser diode is generally based on optical fiber coupling module to output the laser. Using the beam-shaping and fiber-coupling technology to improve the quality of output beam light, we present a kind of high-power and high-brightness semiconductor laser module, which can output 13.22 W through the optical fiber. Based on 915 nm GaAs semiconductor laser diode which has output power of 13.91 W, we describe a thoroughly detailed procedure for reshaping the beam output from the semiconductor laser diode and coupling the beam into the optical fiber of which the core diameter is 105 μm and the numerical aperture is 0.18. We get 13.22 W from the output fiber of the module at 14.5 A, the coupling efficiency of the whole module is 95.03% and the brightness is 1.5 MW/cm2-str. The output power of the single chip semiconductor laser module achieves the advanced level in the domestic use.展开更多
Fabry-Perot(F-P)nanocavity-type electrochromic devices with multicolor tunability have attracted significant interest in the past two years for their potential uses in a wide variety of applications,such as electronic...Fabry-Perot(F-P)nanocavity-type electrochromic devices with multicolor tunability have attracted significant interest in the past two years for their potential uses in a wide variety of applications,such as electronic display,military camouflage,and dynamic decoration.However,challenges such as insufficient brightness,lengthy switching times,and poor cycling stability have yet to be overcome.Herein,we demonstrate electrochromic electrodes based on ITO/Cu as both the current collector and the reflective layer,with WO_(3 )as the electrochromic material,forming a unique three-layered structure.The constituted WO_(3 )/ITO/Cu films present a high brightness value of about 84%before coloration,and a decent brightness value of 48%after coloration at−0.8V.Moreover,a fast switching time between different coloration states(tc=2.2s;tb=1s)is recorded,attributed to the extremely low sheet resistivity of the ITO/Cu current collector.The films also reveal excellent electrochemical cycling stability across 2000 cycles.展开更多
This paper studies the properties of a kind of portable ultra-bright microfocus x-ray source with the Monte-Carlo method in detail. The new x-ray source consists of an electron-emission system, an electrostatic focusi...This paper studies the properties of a kind of portable ultra-bright microfocus x-ray source with the Monte-Carlo method in detail. The new x-ray source consists of an electron-emission system, an electrostatic focusing system and a metal target. A crystal Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted electrode compose the triode electrode electron-gun system. Two equal radius cylinder electrodes form the focusing system. The key factors determining the focus properties of the electron beam such as the ratio Dw/H, grid bias Vg, and the properties of the extracted electrode arc numerically studied. The calculated results reveal that when Dw/H, Vg, the length of the extracted electrode, and the distance between the grid and the extracted electrode equals 5, q）.6 kV, 10 mm, and 8 mm respectively, the electron beam focal spot can be concentrated down to 9 μm in radius and a reasonable focal length about 72.5 mm can be achieved, at the same time, the cathode emission currents can be as high as 30 mA.展开更多
A hybrid cavity structure based on individual laser diode integrating coherent beam combining(CBC)and spectral beam combining(SBC)is demonstrated.The CBC structure is used to enhance laser output power while optimizin...A hybrid cavity structure based on individual laser diode integrating coherent beam combining(CBC)and spectral beam combining(SBC)is demonstrated.The CBC structure is used to enhance laser output power while optimizing beam quality,and the SBC structure is employed to further increase laser output power.An output power of 1.42 W was obtained at 0.55 A,with a high combining efficiency of 87.2%.Additionally,the brightness of this structure is 58.65 MW·cm^(-2)·sr^(-1),which is 3.66times that of a single laser diode.The entire structure provides a new approach for increasing the output power and optimizing the beam quality of the laser diode.展开更多
In this paper, the synoptic process of convective heavy rain in Pingxiang and heavy rain in some areas from July 9 to 10, 2020 is analyzed by using high-altitude weather maps, automatic regional station data, sounding...In this paper, the synoptic process of convective heavy rain in Pingxiang and heavy rain in some areas from July 9 to 10, 2020 is analyzed by using high-altitude weather maps, automatic regional station data, sounding data maps and satellite cloud pictures. The results show that (1) The high pressure in the upper atmosphere is maintained, the circulation situation of "two troughs and one ridge" in the middle and high latitudes is stable, the large trough in East Asia is stable and less moving, and the low trough in Lake Baikal is deepening southward to guide cold air southward;The subtropical high at low latitudes strengthened westward and remained stable with little movement. The warm and humid air flow at the northwest side provided continuous water vapor transportation for Pingxiang. The strong convergence of the southward dry and cold air and the southward warm and humid air, combined with the favorable conditions of convergence in the lower level and divergence in the upper level, constituted the basic circulation situation of the rainstorm. (2) The warm and humid air flow in the middle and low levels transports a large amount of unstable energy and abundant water vapor, and the convergence line on the ground triggers the release of unstable energy, which, in combination with the uplift of the shear system in the lower level, results in obvious convective precipitation in Pingxiang. (3) Convective monomer is continuously generated and developed near the shear line, and moves and merges along the system direction. The region matching degree between the highlight area and the short-term strong precipitation on the cloud image is very high. The highlight area and the system development direction have good reference function for the short-term and imminent forecast of the precipitation process that is occurring.展开更多
High-brightness laser lighting faces grave challenges in the development of laser-driven color converters that simultaneouslypossess excellent optical performance and superior heat dissipation.Herein,a reflective sand...High-brightness laser lighting faces grave challenges in the development of laser-driven color converters that simultaneouslypossess excellent optical performance and superior heat dissipation.Herein,a reflective sandwich color converter of phosphor-in-glass film with sapphire and alumina(sapphire@PiGF@alumina,abbreviated as S@PiGF@A)is designed and prepared via a thermocompression bonding method.Owing to the high thermal conductivity and double-sided heat dissipation channels of alumina and sapphire,the S@PIGF@A color converter can withstand high laser power density and produce ultrahigh luminescence.Consequently,the optimized S@PIGF@A converter yields white light with an ultrahigh luminous flux of 6749 Im at a laser power density saturation threshold of 47.70 W/mm,which is 2.44 times that of traditional PIGF@alumina colorl converter(2522 Im@19.53 W/mm).These findings provide valuable guidelines to design high-quality PiGF color converter for high-brightness laser-driven white lighting.展开更多
A spectrum-tunable 650 nm semiconductor laser dense spectral beam combining(DSBC)system has been successfully realized for the first time,to the best of our knowledge.This system is constructed based on a dual-grating...A spectrum-tunable 650 nm semiconductor laser dense spectral beam combining(DSBC)system has been successfully realized for the first time,to the best of our knowledge.This system is constructed based on a dual-grating DSBC(DG-DSBC)module,which can realize DSBC with any preset spectrum width under ideal conditions.In this paper,three sets of spectrum-tunable examples are finally given.The combined spectra are stabilized at 4.89,8.04,and 10.17 nm,with a maximum beam combining efficiency of about 88.27%.The brightness of this system is improved by more than 71%compared with that of the traditional DSBC structure.展开更多
In this paper,a polarization full-feedback open-loop spectral beam combining(PFF-SBC)structure based on double-ridge stripe semiconductor parity-time-symmetric laser diodes(PTLDs)is proposed and demonstrated.The beam ...In this paper,a polarization full-feedback open-loop spectral beam combining(PFF-SBC)structure based on double-ridge stripe semiconductor parity-time-symmetric laser diodes(PTLDs)is proposed and demonstrated.The beam quality of the PTLD is optimized,and the combining efficiency is improved using the methods of polarization separation and full feedback.The maximum output power is up to 2.71 W,which leads to a spectral beam combining efficiency of 83.4%and a grating diffraction efficiency of 95.51%under continuous current operation at a current of 2.3 A.Additionally,the brightness of the SBC module is 116.2 MW·cm^(-2)sr^(-1)at a current of 1.6 A,which is 3.5 times that of a single PTLD.The PFF-SBC strategy provides,to our knowledge,a new approach for increasing the beam brightness of PTLDs.展开更多
Developing light-emitting diodes(LEDs)with the merits of low driving and high brightness has always been attractive.Considering the carrier dynamic process under electroexcitation,the built-in potential(V_(bi))represe...Developing light-emitting diodes(LEDs)with the merits of low driving and high brightness has always been attractive.Considering the carrier dynamic process under electroexcitation,the built-in potential(V_(bi))represents the moment that the photons start to be produced in a LED.However,it has not been carefully studied and discussed.Here,we observed that by employing an interface regulation strategy to enhance hole concentration,the V_(bi)of quantum dot LEDs(QLEDs)can be reduced.Combined with the characterization methods of Mott–Schottky(MS)and scanning Kelvin probe microscopy(SKPM),the key indicator of V_(bi)on driving voltage for QLEDs is confirmed.Profiting from the reduction of V_(bi),a record-breaking ultra-low turn-on voltage of 2.2 V(@1 cd/m^(2))is achieved in a blue QLED.The blue QLED shows an advantage of high brightness under low driving voltages,i.e.,1000 cd/m^(2)@3.10 V and 5000 cd/m^(2)@3.88 V.This work proposes a reference strategy to predict and analyze the driving voltage issue,which is beneficial to facilitating the development of low-driving QLEDs in the future.展开更多
文摘The output radiation from the 100μm×1μm aperture of a high power Laser Diode (LD) is efficiently coupled into a 50μm multimode optical fiber.The fiber output of the high power LD with high brightness and high power density is achieved.The power density is up to 3 6×104W/cm2 and the coupling efficiency is 70%.The extreme divergence and the astigmatism of high power LDs require the optics with complex lens structures and high performance.A double-curved lens with two crossed cylindrical lenses structured on both sides of the glass substrate is used in the coupling system.
基金the National Basic Research Program of China(Grant No.2009CB623604)the National Natural Science Foundation of China(Grant Nos.61204087,51173049,U0634003,61036007,and 60937001)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant Nos.2011ZB0002 and 2011ZM0009)China Postdoctoral Science Foundation
文摘High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes （HWOLEDs） with the configuration of indium tin oxide （ITO）/ N, N, N, N-tetrakis（4-methoxyphenyl）-benzidine （MeO-TPD）： tetrafluoro-tetracyanoqino dimethane （F4-TCNQ）/N,N-di（naphthalene-1-yl）-N,N-diphenyl-benzidine （NPB）/ 4,4-N,N-dicarbazolebiphenyl （CBP）： iridium （III） diazine complexes （MPPZ） 2 Ir（acac）/NPB/2-methyl-9,10-di（2-naphthyl）anthracene （MADN）： p-bis（p-N,N-di-phenyl-aminostyryl）benzene （DSA-ph）/bis（10-hydroxybenzo[h] quino-linato）beryllium complex （Bebq2）/LiF/Al have been fabricated and characterized. The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V, and the Commission Internationale de l’Eclairage （CIE） chromaticity coordinates are almost constant during a large voltage change of 6–12 V. Furthermore, a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained, which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2. We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/blue-fluorescence in the device. Undoubtedly, this is one of the most exciting results in two-wavelength HWOLEDs up to now.
文摘A new compact XGA projection is designed with three 0.99" liquid crystal panels. By using 275W UHP lamp, above 3000 ANSI lumens could be achieved with the uniformity of 85%. The color temperature is 6742K.
基金Y.L.acknowledges financial supports from the National Natural Science Foundation of China(No.21772084)Fundamental Research Layout of Shenzhen(No.JCY20180504165657443)+2 种基金H.S.thanks the National Natural Science Foundation of China(Nos.11727810,61720106009 and 21603074)the Science and Technology Commission of Shanghai Municipality(No.19JC1412200)for funding support and the ECNU Multifunctional Platform for Innovation(001)and HPC Research Computing Team for providing computational and storage resourcesX.Z thanks the funding supports from the National Natural Science Foundation of China(Nos.91859101,81971744,and U1932107).
文摘It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report a molecular engineering approach to afford NIR-Ⅱ fluorophores with these merits based on fused-ring acceptor(FRA)molecules.Dioctyl 3,4-propylenedioxy thiophene(PDOT-C8)is utilized as the bridging donor to replace 3-ethylhexyloxy thiophene(3-EHOT),leading to more than 20 times enhancement of brightness.The nanofluorophores(NFs)based on the optimized CPTIC-4F molecule exhibit an emission peak of 1,110 nm with a fluorescence quantum yield(QY)of 0.39%(QY of IR-26 is 0.050%in dichloroethane as reference)and peak absorption coefficient of 14.5 x 10^4 M^-1·cm^-1 in aqueous solutions,which are significantly higher than those of 3-EHOT based COTIC-4F NFs.It is found that PDOT-C8 can weaken intermolecular aggregation,enhance protection of molecular backbone from water,and decrease backbone distortion,beneficial for the high brightness.Compared with indocyanine green with same injection dose,CPTIC-4F NFs show 10 times higher signal-to-background ratio for whole body vessels imaging at 1,300 nm long pass filters.
基金financially supported by the Swedish Energy Agency Energimyndigheten(48758-1)the European Research Council Consolidator Grant(LEAP,101045098)+1 种基金the National Natural Science Foundation of China(52102217)the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Link?ping University(Faculty Grant SFO-Mat-LiU 2009-00971)。
文摘We report a simple,effective,and universal lattice reconstruction approach to improve the quality of perovskite films by using nonpolar solvents with high Gutmann donor numbers(DNs).We find that high-DN nonpolar solvents,for instance,ethyl acetate,can interact with perovskite precursors.Such a solvent can make the perovskite lattice more ordered and“harder”and promote the formation of heterostructures with low-dimensional perovskite impurities and residual solvent molecules.As a result,the latticereconstructed perovskite films exhibit reduced defect densities and suppressed ion migration.The resultant mixed-halide blue perovskite light-emitting diodes(PeLEDs)show greatly enhanced tolerance to high driving current densities and voltages,demonstrating high brightness,outstanding color stability and low efficiency roll-off.Our work provides a deep understanding of the interactions between nonpolar solvents and perovskites and offers useful guidelines for further development of high-power PeLEDs.
基金supported by the Development Foundation for Electronic and Information Industry(2010),the Science and Technology Commission of Shanghai Municipality(Grant No.10DZ1140502)the Mechatronics Engineering Innovation Group Project from the Education Commission of Shanghai Municipality
文摘The research of high-brightness organic light-emitting diodes, as an important branch of organic light-emitting diodes （OLEDs）, makes it possible for achieving high-brightness lighting source and lasing. Heat dissipation and efficiency roll off, as two main factors, affect the brightness of the OLEDs heavily. In this paper, high-brightness OLEDs are obtained by utilizing pulse voltage, small areas and micro-cavity structure to minimize the effect of the two factors. The major advances, ongoing challenges and future perspectives of this research frontier are also critically discussed.
文摘Inorganic luminescent materials have been widely used as color converters for applications in lighting and displays [1-6].In recent years, laser-driven solid-state lighting based on phosphor-converted white laser diode (pc-WLD) technology, which is commonly fabricated with the combination of "blue LD+color converters", is rising for high-power lighting due to its super-high brightness, reliability and compactness [7,8].
文摘Fiber-coupled laser pumps with low size,weight and power consumption(SWaP)have become more and more compelling for applications in both industrial and defense applications.This study presents an innovative approach employing the spectral beam combining technique and double-junction laser diode chips to create efficient,high-power,high-brightness fiber-coupled packages.We successfully demonstrated a wavelength-stabilized pump module capable of delivering over 560 W of ex-fiber power with an electro-optical conversion efficiency of 55%from a 135μm diameter,0.22 numerical aperture fiber.The specific mass and volume metrics achieved are 0.34 kg/kW and 0.23 cm^(3)/W,respectively.The module exhibits a stabilized spectrum with a 3.6 nm consistent interval of two spectral peaks and a 4.2 nm full width at half maximum across a wide range of operating currents.
文摘The n type GaAs substrates are used and their conductive type is changed to p type by tunnel junction for AlGaInP light emitting diodes(TJ LED),then n type GaP layer is used as current spreading layer.Because resistivity of the n type GaP is lower than that of p type,the effect of current spreading layer is enhanced and the light extraction efficiency is increased by the n type GaP current spreading layer.For TJ LED with 3μm n type GaP current spreading layer,experimental results show that compared with conventional LED with p type GaP current spreading layer,light output power is increased for 50% at 20mA and for 66 7% at 100mA.
文摘A novel type of high power edge-emitting semiconductor laser （SL） with extended vertical photonic band crystal （PBC） waveguide was reviewed. Simulations predict narrow beam divergence, resulting from the thick PBC waveguide, to be independent of realistic variations of the growth parameters. Narrow ridge lasers fabricated along the simulations indeed demonstrate superior output power, narrow beam divergence, circular beam profile, excellent beam quality and very low astigmatism. Efficient fiber coupling decisive for most applications was thus eased. Stability of the laser under a wide range of operating temperature was demonstrated. Ultrashort pulses with few ps of duration at GHz repetition rates were generated by passively mode locking the lasers.
文摘Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality of the laser diode is very poor, the 915 nm laser diode is generally based on optical fiber coupling module to output the laser. Using the beam-shaping and fiber-coupling technology to improve the quality of output beam light, we present a kind of high-power and high-brightness semiconductor laser module, which can output 13.22 W through the optical fiber. Based on 915 nm GaAs semiconductor laser diode which has output power of 13.91 W, we describe a thoroughly detailed procedure for reshaping the beam output from the semiconductor laser diode and coupling the beam into the optical fiber of which the core diameter is 105 μm and the numerical aperture is 0.18. We get 13.22 W from the output fiber of the module at 14.5 A, the coupling efficiency of the whole module is 95.03% and the brightness is 1.5 MW/cm2-str. The output power of the single chip semiconductor laser module achieves the advanced level in the domestic use.
基金National Key Research and Development Program of China(2020YFB1505703)This work is supported by the National Natural Science Foundation of China(52172299,22175198,51972331)+2 种基金Z.G.Z would like to acknowledge the support from the External Cooperation Program of the Chinese Academy of Sciences(121E32KYSB20190008)Six Talent Peaks Project of Jiangsu Province(XCL-170).S.C would like to acknowledge the support from the Youth Innovation Promotion Association,CAS(2018356)Outstanding Youth Fund of Jiangxi(20192BCBL23027).
文摘Fabry-Perot(F-P)nanocavity-type electrochromic devices with multicolor tunability have attracted significant interest in the past two years for their potential uses in a wide variety of applications,such as electronic display,military camouflage,and dynamic decoration.However,challenges such as insufficient brightness,lengthy switching times,and poor cycling stability have yet to be overcome.Herein,we demonstrate electrochromic electrodes based on ITO/Cu as both the current collector and the reflective layer,with WO_(3 )as the electrochromic material,forming a unique three-layered structure.The constituted WO_(3 )/ITO/Cu films present a high brightness value of about 84%before coloration,and a decent brightness value of 48%after coloration at−0.8V.Moreover,a fast switching time between different coloration states(tc=2.2s;tb=1s)is recorded,attributed to the extremely low sheet resistivity of the ITO/Cu current collector.The films also reveal excellent electrochemical cycling stability across 2000 cycles.
基金supported by the Major Program of the National Natural Science Foundation of China(Grant No 60532090)the National Natural Science Foundation of China(Grant No 60771048)
文摘This paper studies the properties of a kind of portable ultra-bright microfocus x-ray source with the Monte-Carlo method in detail. The new x-ray source consists of an electron-emission system, an electrostatic focusing system and a metal target. A crystal Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted electrode compose the triode electrode electron-gun system. Two equal radius cylinder electrodes form the focusing system. The key factors determining the focus properties of the electron beam such as the ratio Dw/H, grid bias Vg, and the properties of the extracted electrode arc numerically studied. The calculated results reveal that when Dw/H, Vg, the length of the extracted electrode, and the distance between the grid and the extracted electrode equals 5, q）.6 kV, 10 mm, and 8 mm respectively, the electron beam focal spot can be concentrated down to 9 μm in radius and a reasonable focal length about 72.5 mm can be achieved, at the same time, the cathode emission currents can be as high as 30 mA.
基金supported by the Key Research and Development Program of Shandong Province(Nos.2023ZLYS03 and 2022CXGC020104)the Key-Area Research and Development Program of Guangdong Province(No.2020B090922003)。
文摘A hybrid cavity structure based on individual laser diode integrating coherent beam combining(CBC)and spectral beam combining(SBC)is demonstrated.The CBC structure is used to enhance laser output power while optimizing beam quality,and the SBC structure is employed to further increase laser output power.An output power of 1.42 W was obtained at 0.55 A,with a high combining efficiency of 87.2%.Additionally,the brightness of this structure is 58.65 MW·cm^(-2)·sr^(-1),which is 3.66times that of a single laser diode.The entire structure provides a new approach for increasing the output power and optimizing the beam quality of the laser diode.
文摘In this paper, the synoptic process of convective heavy rain in Pingxiang and heavy rain in some areas from July 9 to 10, 2020 is analyzed by using high-altitude weather maps, automatic regional station data, sounding data maps and satellite cloud pictures. The results show that (1) The high pressure in the upper atmosphere is maintained, the circulation situation of "two troughs and one ridge" in the middle and high latitudes is stable, the large trough in East Asia is stable and less moving, and the low trough in Lake Baikal is deepening southward to guide cold air southward;The subtropical high at low latitudes strengthened westward and remained stable with little movement. The warm and humid air flow at the northwest side provided continuous water vapor transportation for Pingxiang. The strong convergence of the southward dry and cold air and the southward warm and humid air, combined with the favorable conditions of convergence in the lower level and divergence in the upper level, constituted the basic circulation situation of the rainstorm. (2) The warm and humid air flow in the middle and low levels transports a large amount of unstable energy and abundant water vapor, and the convergence line on the ground triggers the release of unstable energy, which, in combination with the uplift of the shear system in the lower level, results in obvious convective precipitation in Pingxiang. (3) Convective monomer is continuously generated and developed near the shear line, and moves and merges along the system direction. The region matching degree between the highlight area and the short-term strong precipitation on the cloud image is very high. The highlight area and the system development direction have good reference function for the short-term and imminent forecast of the precipitation process that is occurring.
基金supported by the Key Research and Development Program of Guanzgxi Zhuang Autonomous Region(No.AB25069373)the Science and Technology Project of Shenzhen City(No.JCYJ20230807110907016)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515010001 and 2024A1515011445)the Shenzhen Postdoctoral Research Funding Project.
文摘High-brightness laser lighting faces grave challenges in the development of laser-driven color converters that simultaneouslypossess excellent optical performance and superior heat dissipation.Herein,a reflective sandwich color converter of phosphor-in-glass film with sapphire and alumina(sapphire@PiGF@alumina,abbreviated as S@PiGF@A)is designed and prepared via a thermocompression bonding method.Owing to the high thermal conductivity and double-sided heat dissipation channels of alumina and sapphire,the S@PIGF@A color converter can withstand high laser power density and produce ultrahigh luminescence.Consequently,the optimized S@PIGF@A converter yields white light with an ultrahigh luminous flux of 6749 Im at a laser power density saturation threshold of 47.70 W/mm,which is 2.44 times that of traditional PIGF@alumina colorl converter(2522 Im@19.53 W/mm).These findings provide valuable guidelines to design high-quality PiGF color converter for high-brightness laser-driven white lighting.
基金supported by the Key Research and Development Program of Shandong Province(Nos.2023ZLYS03 and 2022CXGC020104)。
文摘A spectrum-tunable 650 nm semiconductor laser dense spectral beam combining(DSBC)system has been successfully realized for the first time,to the best of our knowledge.This system is constructed based on a dual-grating DSBC(DG-DSBC)module,which can realize DSBC with any preset spectrum width under ideal conditions.In this paper,three sets of spectrum-tunable examples are finally given.The combined spectra are stabilized at 4.89,8.04,and 10.17 nm,with a maximum beam combining efficiency of about 88.27%.The brightness of this system is improved by more than 71%compared with that of the traditional DSBC structure.
基金supported by the Key R&D Program of Shandong Province,China(Nos.2023ZLYS03 and 2024CXPT098)the National Key R&D Program of China(No.2023YFB3609800)。
文摘In this paper,a polarization full-feedback open-loop spectral beam combining(PFF-SBC)structure based on double-ridge stripe semiconductor parity-time-symmetric laser diodes(PTLDs)is proposed and demonstrated.The beam quality of the PTLD is optimized,and the combining efficiency is improved using the methods of polarization separation and full feedback.The maximum output power is up to 2.71 W,which leads to a spectral beam combining efficiency of 83.4%and a grating diffraction efficiency of 95.51%under continuous current operation at a current of 2.3 A.Additionally,the brightness of the SBC module is 116.2 MW·cm^(-2)sr^(-1)at a current of 1.6 A,which is 3.5 times that of a single PTLD.The PFF-SBC strategy provides,to our knowledge,a new approach for increasing the beam brightness of PTLDs.
基金support was from the National Key Research and Development Program of China(No.2022YFB3606502)the National Natural Science Foundation of China(Nos.52131304,62004101,62261160392,and 22022205)+1 种基金Jiangsu graduate and practice innovation program(No.KYCX23_0456)the Fundamental Research Funds for the Central Universities(No.30920041117).
文摘Developing light-emitting diodes(LEDs)with the merits of low driving and high brightness has always been attractive.Considering the carrier dynamic process under electroexcitation,the built-in potential(V_(bi))represents the moment that the photons start to be produced in a LED.However,it has not been carefully studied and discussed.Here,we observed that by employing an interface regulation strategy to enhance hole concentration,the V_(bi)of quantum dot LEDs(QLEDs)can be reduced.Combined with the characterization methods of Mott–Schottky(MS)and scanning Kelvin probe microscopy(SKPM),the key indicator of V_(bi)on driving voltage for QLEDs is confirmed.Profiting from the reduction of V_(bi),a record-breaking ultra-low turn-on voltage of 2.2 V(@1 cd/m^(2))is achieved in a blue QLED.The blue QLED shows an advantage of high brightness under low driving voltages,i.e.,1000 cd/m^(2)@3.10 V and 5000 cd/m^(2)@3.88 V.This work proposes a reference strategy to predict and analyze the driving voltage issue,which is beneficial to facilitating the development of low-driving QLEDs in the future.
