Photon pairs with large nondegeneracy have recently attracted increasing interest, which gives rise to an urgent demand for revealing their complete and accurate spectral distribution. By thoroughly analyzing parametr...Photon pairs with large nondegeneracy have recently attracted increasing interest, which gives rise to an urgent demand for revealing their complete and accurate spectral distribution. By thoroughly analyzing parametric down-conversion(PDC), we put forward a model to directly describe the spatial-spectral distribution of these photon pairs, which is experimentally demonstrated by a 532-nm pumped type-I PDC in a beta barium borate(BBO) crystal. The measured spectral curves show good agreement with the theoretical predictions over the entire spectral range. We further demonstrate that, as signal wavelength increases, the photon pairs are initially spectrally distinguishable, then partly indistinguishable, finally completely indistinguishable with a maximum bandwidth of approximately 500 nm. Utilizing photon-number-resolving single-photon detectors(SPD), we observe the average photon number decreases significantly more slowly than the spectral intensity as the wavelength deviates from the peak, and the photon numbers follow a quasi-Poisson distribution well for wavelengths around the peak, but a thermal distribution better describes the statistics near the spectral boundaries. Finally,we use the signal photons as the trigger to generate heralded Fock states up to 10 photons in near-infrared range, which are suitable for quantum simulation and quantum key distribution in optical fiber networks.展开更多
A series of near-infrared(NIR)down-conversion phosphors of La_(3)Ga_(5)SiO_(14)(LGS):Ce^(3+)/Yb^(3+)were synthesized via high-temperature solid-state reaction.Under excitation at 345 nm,the phosphors show strong NIR e...A series of near-infrared(NIR)down-conversion phosphors of La_(3)Ga_(5)SiO_(14)(LGS):Ce^(3+)/Yb^(3+)were synthesized via high-temperature solid-state reaction.Under excitation at 345 nm,the phosphors show strong NIR emission around 978 nm,which matches well with the optimal spectral response of crystalline silicon(c-Si)solar cells.The emission spectra and decay curves were used to demonstrate the energy transfer from Ce^(3+)to Yb^(3+).The energy transfer mechanism was discussed in detail,indicating that the energy transfer from Ce^(3+)to Yb^(3+)is dominated by a single photon process,and the energy transfer efficiency is up to 51%.In addition,La_(3)Ga_(5-z)Al_(2)SiO_(14)(z=0,1,2,3):Ce^(3+)/Yb^(3+)were also synthesized.The NIR emission intensity of La_(3)Ga_(2)Al_(3)SiO_(14):1%Ce^(3+)/5%Yb^(3+)is 4.6 times that of LGS:1%Ce^(3+)/5%Yb^(3+),and the thermal relaxation was used to explain this phenomenon.The results show that La_(3)Ga_(5-z)Al_(2)SiO_(14)(z=0,1,2,3):1%Ce^(3+)/5%Yb^(3+)phosphors have the potential to increase the conversion efficiency of c-Si solar cells.展开更多
In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles we...In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles were tested at room temperature un-der a near-infrared photo source （980 nm） and UV-vis photo source, respectively.The results indicated thatα-TeO2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence. Theα-TeO2：Ho3＋/Yb3＋nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation, ascribed to the5S2→5I8 and5F5→5I8（Ho3＋） transitions, and weaker down-conversion emission at 545 nm under 455 nm excitation, ascribed to the5S2→5I8（Ho3＋） transitions. Theα-TeO2：Eu3＋nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation, attributed to the5D0→7F1 and 5D0→7F2 （Eu3＋） transitions. Possessing the advantages of these two luminescent materials, the as-prepared tri-doped samples ofα-TeO2：0.5Ho3＋/10Yb3＋/3Eu3＋ （mol.%）nanoparticles could successfully emit visible light via both up- and down-conversion modes.展开更多
Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single ph...Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single photons emitted from single In As quantum dot at 864 nm is down converted to 1552 nm by using a fiber-coupled periodically poled lithium niobate（PPLN） waveguide and a 1.95 μmm pump laser, and the frequency conversion efficiency is ~40%. The singlephoton purity of quantum dot emission is preserved during the down-conversion process, i.e., g^（（2））（0）, only 0.22 at 1552 nm.This present technique advances the Ⅲ-Ⅴ semiconductor quantum dots as a promising platform for long-distance quantum communication.展开更多
We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variati...We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variation models and our simulation results show that thickness variations in several nanometers can induce distinct effects on the central peak of the spectrum,such as narrowing,broadening,and splitting.We also prove that the effects of positive and negative variations can be canceled and thus lead to a variation-robust feature and an ultra-broad bandwidth.Our study may promote the development of on-chip photon sources in the LNOI platform,as well as opens up a way to engineer photon frequency state.展开更多
We studied the process of polariton conversion in a 3-mode nonlinear optomechanical system.Compared with the standard 2-mode optomechanical system,we find a much larger conversion rate of polariton modes can be achiev...We studied the process of polariton conversion in a 3-mode nonlinear optomechanical system.Compared with the standard 2-mode optomechanical system,we find a much larger conversion rate of polariton modes can be achieved under typical dissipation conditions.To obtain a transparent understanding of the relevant physical process,we show that in the large detuned case,the cavity can be eliminated adiabatically,resulting in a parametric down-conversion(PDC)interaction between two phononic polariton modes.By tuning cavity detuning,the nonlinear interaction can be enhanced with the frequency-matching condition.Results from analytical treatment based on the effective PDC model agree with the numerical simulation.Such a system provides potential applications in nonlinear phononics.展开更多
By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the dege...By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the degenerate and non-degenerate coupled parametric down-conversion system with driving term. By means of this invariant and the Lewis-Riesenfeld quantum invariant theory, we obtain closed formulae of the quantum state and the evolution operator of the system. We show that the time evolution of the quantum system directly leads to production of various generalized one- and two-mode combination squeezed states, and the squeezed effect is independent of the driving term of the Hamiltonian. In some special cases, the current solution can reduce to the results of the previous works.展开更多
In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodul...In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodulate radio signals. This article describes concepts, theory, and design principles for SDR down-conversion and up-conversion. Design issues in SDR down-conversion are discussed, and two different architectures, super-heterodyne and direct-conversion, are proposed. Design issues in SDR up-conversion are also discussed, and trade-offs in the design of filters, mixers, NCO, DAC, and signal processing are highlighted.展开更多
A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing （FWM） processes is made. The structure and its tuning characteris- ti...A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing （FWM） processes is made. The structure and its tuning characteris- tic are designed by the aid of FDTD mode solution. The laser structure is grown by molecular beam epitaxy and processed to laser diode through the semiconductor manufacturing technology. Fourier transform infrared spectroscopy is applied to record wavelength information. Pump around 1.071 μm, signal around 1.77μm, idler around 2.71 μm and FWM signal around 1.35μm are observed at an injection current of 560mA. The influ- ences of temperature, carrier density and pump wavelength on tuning characteristic are shown numerically and experimentally.展开更多
Parametric down-conversion（PDC） sources play an important role in quantum information processing, therefore characterizing their properties is necessary. Here we present a statistical model to assess the properties ...Parametric down-conversion（PDC） sources play an important role in quantum information processing, therefore characterizing their properties is necessary. Here we present a statistical model to assess the properties of the PDC source with certain distribution, such as the brightness and photon channel transmissions, we only need to measure the singles and coincidences counts in a few seconds. Furthermore, we validate the model by applying it to a PDC source generating highly non-degenerate photon pairs. The results of the experiment indicate that our method is more simple, efficient, and less time consuming.展开更多
To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the character...To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the characteristics of low-tempe rature sulfuric acid deco mposition.When a single monazite was leached using 75 wt% H_(2)SO_(4) solution with phosphoric acid,the size and number of monazite particles in the washing slag gradually decrease with the increase in phosphoric acid content in the leaching solution.The monazite phase can hardly be found in the slag when the phosphoric acid content reaches 70 g/L,which indicates that phosphoric acid is favorable for monazite decomposition.The mixed rare earth concentrate was leached by 75 wt% H_(2)SO_(4) containing 70 g/L phosphoric acid,the mineral compositions of the washing slag are only gypsum and unwashed rare earth sulfuric acid.After cyclic leaching of75 wt% H_(2)SO_(4),the mineral compositions of the primary leaching washing slag are mainly undecomposed monazite,rare earth sulfate and calcium sulfate.However,monazite is not found in the mineral phase of the second and third leaching washing slag.The leaching rates of rare earth and phosphorus gradually increase with the increase in cyclic leaching times.In addition,the phosphoric acid content in the leaching solution increases with the increase in the number of cyclic leaching time.However,the rising trend decreases when the phosphoric acid content reaches 50 g/L by adsorption and crystallization of phosphoric acid.A small amount of water can be used to clean the leaching residue before washing to recover the more soluble phosphorus acid according to the difference of dissolution between phosphoric acid and rare earth sulfuric acid.展开更多
The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalys...The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.展开更多
Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity re...Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.展开更多
The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples w...The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples with the oxide demonstrate a long-lasting photoluminescence(PL)under sunlight and ultra-violet(UV)illumination.Room-temperature the PL spectra reveal a wide multicomponent band spreading over all the visible spectral regions.The short-wavelength part of the band is ascribed to the cellulose-related luminescence,while the long-wavelength PL component with maxima near 540 nm corresponds to the luminescence of the SrAl_(2)O_(4):Eu,Dy phosphor.The dependency of the PL intensity on oxide concentration suggests the reabsorption of cellulose emission by the oxide and vice versa.The study of the dielectric properties of composite papers shows the presence of dielectric relaxations at low temperatures(T~−50℃).Similar cellulose materials to those studied can be considered as alternatives for artificial petroleum-based polymers.Low cost,eco-friendliness,biocompatibility,and the simplicity of recycling are among the main advantages of these materials.They are produced from the cellulose which is one of the most abundant renewable materials in nature.The data on the mechanical,dielectric,and optical properties indicate that the papers studied can be used in flexible lighting devices,WLEDs,coating,markers,labels,etc.展开更多
Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius o...Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.展开更多
This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indic...This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.展开更多
Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material ...Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.展开更多
A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable ...A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable luminous efficiency of Mn^(2+).The energy transfer between Eu^(2+)and Mn^(2+)significantly boosts both internal quantum efficiency(IQE)and external quantum efficiency(EQE)of the phosphor,achieving values of 72.5%and 42.6%,respectively.Additionally,the phosphor demonstrates exceptional thermal stability,at150℃.maintaining 71.49%of its initial emission intensity.The emission spectrum of the phosphor closely matches the chlorophyll's absorption spectra,with similarities of 75.06%and 94.52%,respectively.This was further confirmed through a fabricated LED with a n-UV chip(395 nm).To further assess the potential for agritech applications,a light-conversion film incorporating the developed phosphor in PDMS glue was prepared.An outdoor cultivation trial with Chlorella showed that the algae's growth rate improves by 27.3%relative to a control group.These results reveal the significant potential of the Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)phosphor for enhancing plant growth in practical applications.展开更多
To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through...To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.展开更多
Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge ...Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 62075010)。
文摘Photon pairs with large nondegeneracy have recently attracted increasing interest, which gives rise to an urgent demand for revealing their complete and accurate spectral distribution. By thoroughly analyzing parametric down-conversion(PDC), we put forward a model to directly describe the spatial-spectral distribution of these photon pairs, which is experimentally demonstrated by a 532-nm pumped type-I PDC in a beta barium borate(BBO) crystal. The measured spectral curves show good agreement with the theoretical predictions over the entire spectral range. We further demonstrate that, as signal wavelength increases, the photon pairs are initially spectrally distinguishable, then partly indistinguishable, finally completely indistinguishable with a maximum bandwidth of approximately 500 nm. Utilizing photon-number-resolving single-photon detectors(SPD), we observe the average photon number decreases significantly more slowly than the spectral intensity as the wavelength deviates from the peak, and the photon numbers follow a quasi-Poisson distribution well for wavelengths around the peak, but a thermal distribution better describes the statistics near the spectral boundaries. Finally,we use the signal photons as the trigger to generate heralded Fock states up to 10 photons in near-infrared range, which are suitable for quantum simulation and quantum key distribution in optical fiber networks.
基金the Ministry of Science and Technology of the People’s Republic of China(2016YFB0701002)Chinese Academy of Sciences(KFJ-STS-QYZX-069,XDB20000000)Natural Science Foundation of Fujian Province(2019J01127)。
文摘A series of near-infrared(NIR)down-conversion phosphors of La_(3)Ga_(5)SiO_(14)(LGS):Ce^(3+)/Yb^(3+)were synthesized via high-temperature solid-state reaction.Under excitation at 345 nm,the phosphors show strong NIR emission around 978 nm,which matches well with the optimal spectral response of crystalline silicon(c-Si)solar cells.The emission spectra and decay curves were used to demonstrate the energy transfer from Ce^(3+)to Yb^(3+).The energy transfer mechanism was discussed in detail,indicating that the energy transfer from Ce^(3+)to Yb^(3+)is dominated by a single photon process,and the energy transfer efficiency is up to 51%.In addition,La_(3)Ga_(5-z)Al_(2)SiO_(14)(z=0,1,2,3):Ce^(3+)/Yb^(3+)were also synthesized.The NIR emission intensity of La_(3)Ga_(2)Al_(3)SiO_(14):1%Ce^(3+)/5%Yb^(3+)is 4.6 times that of LGS:1%Ce^(3+)/5%Yb^(3+),and the thermal relaxation was used to explain this phenomenon.The results show that La_(3)Ga_(5-z)Al_(2)SiO_(14)(z=0,1,2,3):1%Ce^(3+)/5%Yb^(3+)phosphors have the potential to increase the conversion efficiency of c-Si solar cells.
基金supported by the National Natural Science Foundation of China(21075053)the"Challenge Cup"Undergraduate Extra-curriculum Academics,Science and Technology Works Competition and Student's Platform for Innovation and Entrepreneurship Training Program(201410559056)in Jinan University
文摘In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles were tested at room temperature un-der a near-infrared photo source （980 nm） and UV-vis photo source, respectively.The results indicated thatα-TeO2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence. Theα-TeO2：Ho3＋/Yb3＋nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation, ascribed to the5S2→5I8 and5F5→5I8（Ho3＋） transitions, and weaker down-conversion emission at 545 nm under 455 nm excitation, ascribed to the5S2→5I8（Ho3＋） transitions. Theα-TeO2：Eu3＋nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation, attributed to the5D0→7F1 and 5D0→7F2 （Eu3＋） transitions. Possessing the advantages of these two luminescent materials, the as-prepared tri-doped samples ofα-TeO2：0.5Ho3＋/10Yb3＋/3Eu3＋ （mol.%）nanoparticles could successfully emit visible light via both up- and down-conversion modes.
基金Project supported by the National Key Technologies R&D Program of China(Grant No.2018YFA0306101)the Scientific Instrument Developing Project of Chinese Academy of Sciences(Grant No.YJKYYQ20170032)the National Natural Science Foundation of China(Grant No.61505196)
文摘Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single photons emitted from single In As quantum dot at 864 nm is down converted to 1552 nm by using a fiber-coupled periodically poled lithium niobate（PPLN） waveguide and a 1.95 μmm pump laser, and the frequency conversion efficiency is ~40%. The singlephoton purity of quantum dot emission is preserved during the down-conversion process, i.e., g^（（2））（0）, only 0.22 at 1552 nm.This present technique advances the Ⅲ-Ⅴ semiconductor quantum dots as a promising platform for long-distance quantum communication.
基金Project supported by the National Key R&D Program of China(Grant No.2019YFA0705000)Leading-edge Technology Program of Jiangsu Natural Science Foundation,China(Grant No.BK20192001)the National Natural Science Foundation of China(Grant Nos.51890861,11690031,11974178,and 11627810).
文摘We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variation models and our simulation results show that thickness variations in several nanometers can induce distinct effects on the central peak of the spectrum,such as narrowing,broadening,and splitting.We also prove that the effects of positive and negative variations can be canceled and thus lead to a variation-robust feature and an ultra-broad bandwidth.Our study may promote the development of on-chip photon sources in the LNOI platform,as well as opens up a way to engineer photon frequency state.
基金support from the NSFC(Grant No.12275331)the Penghuanwu Innovative Research Center(Grant No.12047503)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD031602)。
文摘We studied the process of polariton conversion in a 3-mode nonlinear optomechanical system.Compared with the standard 2-mode optomechanical system,we find a much larger conversion rate of polariton modes can be achieved under typical dissipation conditions.To obtain a transparent understanding of the relevant physical process,we show that in the large detuned case,the cavity can be eliminated adiabatically,resulting in a parametric down-conversion(PDC)interaction between two phononic polariton modes.By tuning cavity detuning,the nonlinear interaction can be enhanced with the frequency-matching condition.Results from analytical treatment based on the effective PDC model agree with the numerical simulation.Such a system provides potential applications in nonlinear phononics.
基金supported by the National Natural Science Foundation of China under Grant Nos.40674076 and 40474064the Hunan Natural Science Foundation of China under Grant No.07JJ3123the Scientific Research Fund of Hunan Provincial Education Department under Grant Nos.06C163,05B023,and 06B004
文摘By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the degenerate and non-degenerate coupled parametric down-conversion system with driving term. By means of this invariant and the Lewis-Riesenfeld quantum invariant theory, we obtain closed formulae of the quantum state and the evolution operator of the system. We show that the time evolution of the quantum system directly leads to production of various generalized one- and two-mode combination squeezed states, and the squeezed effect is independent of the driving term of the Hamiltonian. In some special cases, the current solution can reduce to the results of the previous works.
文摘In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodulate radio signals. This article describes concepts, theory, and design principles for SDR down-conversion and up-conversion. Design issues in SDR down-conversion are discussed, and two different architectures, super-heterodyne and direct-conversion, are proposed. Design issues in SDR up-conversion are also discussed, and trade-offs in the design of filters, mixers, NCO, DAC, and signal processing are highlighted.
基金Supported by the National Key Basic Research Program of China under Grant Nos 2013CB933304 and 2014CB643904the National Natural Science Foundation of China under Grant Nos 61435012 and 61274125the Strategic Priority Research Program(B) of Chinese Academy of Sciences under Grant No XDB01010200
文摘A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing （FWM） processes is made. The structure and its tuning characteris- tic are designed by the aid of FDTD mode solution. The laser structure is grown by molecular beam epitaxy and processed to laser diode through the semiconductor manufacturing technology. Fourier transform infrared spectroscopy is applied to record wavelength information. Pump around 1.071 μm, signal around 1.77μm, idler around 2.71 μm and FWM signal around 1.35μm are observed at an injection current of 560mA. The influ- ences of temperature, carrier density and pump wavelength on tuning characteristic are shown numerically and experimentally.
基金Project supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(CAS)(Grant Nos.XDB01030100 and XDB01030300)the National Key Research and Development Program of China(Grant No.2016YFA0302600)the National Natural Science Foundation of China(Grant Nos.61475148 and 61575183)
文摘Parametric down-conversion（PDC） sources play an important role in quantum information processing, therefore characterizing their properties is necessary. Here we present a statistical model to assess the properties of the PDC source with certain distribution, such as the brightness and photon channel transmissions, we only need to measure the singles and coincidences counts in a few seconds. Furthermore, we validate the model by applying it to a PDC source generating highly non-degenerate photon pairs. The results of the experiment indicate that our method is more simple, efficient, and less time consuming.
基金support by the National Natural Science Foundation of Inner Mongolia (2022SHZR1885)Natural Science Foundation of Hebei province (E2022402101,E2022402105)。
文摘To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the characteristics of low-tempe rature sulfuric acid deco mposition.When a single monazite was leached using 75 wt% H_(2)SO_(4) solution with phosphoric acid,the size and number of monazite particles in the washing slag gradually decrease with the increase in phosphoric acid content in the leaching solution.The monazite phase can hardly be found in the slag when the phosphoric acid content reaches 70 g/L,which indicates that phosphoric acid is favorable for monazite decomposition.The mixed rare earth concentrate was leached by 75 wt% H_(2)SO_(4) containing 70 g/L phosphoric acid,the mineral compositions of the washing slag are only gypsum and unwashed rare earth sulfuric acid.After cyclic leaching of75 wt% H_(2)SO_(4),the mineral compositions of the primary leaching washing slag are mainly undecomposed monazite,rare earth sulfate and calcium sulfate.However,monazite is not found in the mineral phase of the second and third leaching washing slag.The leaching rates of rare earth and phosphorus gradually increase with the increase in cyclic leaching times.In addition,the phosphoric acid content in the leaching solution increases with the increase in the number of cyclic leaching time.However,the rising trend decreases when the phosphoric acid content reaches 50 g/L by adsorption and crystallization of phosphoric acid.A small amount of water can be used to clean the leaching residue before washing to recover the more soluble phosphorus acid according to the difference of dissolution between phosphoric acid and rare earth sulfuric acid.
文摘The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.
基金financially supported by the Caiyun Postdoctoral Innovation Project(No.C615300504089)Yunnan Fundamental Research Project(No.202401AS070128)National Natural Science Foundation of China(No.22165031).
文摘Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.
基金financed by the National Research Foundation of Ukraine(Project No.2022.01/0168).
文摘The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples with the oxide demonstrate a long-lasting photoluminescence(PL)under sunlight and ultra-violet(UV)illumination.Room-temperature the PL spectra reveal a wide multicomponent band spreading over all the visible spectral regions.The short-wavelength part of the band is ascribed to the cellulose-related luminescence,while the long-wavelength PL component with maxima near 540 nm corresponds to the luminescence of the SrAl_(2)O_(4):Eu,Dy phosphor.The dependency of the PL intensity on oxide concentration suggests the reabsorption of cellulose emission by the oxide and vice versa.The study of the dielectric properties of composite papers shows the presence of dielectric relaxations at low temperatures(T~−50℃).Similar cellulose materials to those studied can be considered as alternatives for artificial petroleum-based polymers.Low cost,eco-friendliness,biocompatibility,and the simplicity of recycling are among the main advantages of these materials.They are produced from the cellulose which is one of the most abundant renewable materials in nature.The data on the mechanical,dielectric,and optical properties indicate that the papers studied can be used in flexible lighting devices,WLEDs,coating,markers,labels,etc.
基金financially supported by the Natural Science Foundation of China(Nos.22208214,22005190,and 21938005)the Science&Technology Commission of Shanghai Municipality(Nos.20QB1405700,and 19DZ1205500)Zhejiang Key Research and Development Program(No.2020C01128)
文摘Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.
基金funded by the Launch Fund of Hainan University High Level Talent,China(RZ2100003226)the National Natural Science Foundation of China(NSFC-31860728).
文摘This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.
基金supported by the National Natural Science Foundation of China(52403403)Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.
基金supported by the Department of Industry and Information Technology of Gansu Province(2024 Provincial Key Talent Program)the National Natural Science Foundation of China(U22A20136)。
文摘A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable luminous efficiency of Mn^(2+).The energy transfer between Eu^(2+)and Mn^(2+)significantly boosts both internal quantum efficiency(IQE)and external quantum efficiency(EQE)of the phosphor,achieving values of 72.5%and 42.6%,respectively.Additionally,the phosphor demonstrates exceptional thermal stability,at150℃.maintaining 71.49%of its initial emission intensity.The emission spectrum of the phosphor closely matches the chlorophyll's absorption spectra,with similarities of 75.06%and 94.52%,respectively.This was further confirmed through a fabricated LED with a n-UV chip(395 nm).To further assess the potential for agritech applications,a light-conversion film incorporating the developed phosphor in PDMS glue was prepared.An outdoor cultivation trial with Chlorella showed that the algae's growth rate improves by 27.3%relative to a control group.These results reveal the significant potential of the Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)phosphor for enhancing plant growth in practical applications.
基金supported by the National Natural Science Foundation of China(61865003)。
文摘To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.
文摘Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.
