A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric upconversion.A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the upco...A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric upconversion.A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the upconversion from terahertz wave to NIR laser was realized in a lithium niobate crystal.The minimum detectable terahertz energy of 9 p J was realized with the detection dynamic range of 54 d B,which was three orders of magnitude higher than that of commercial Golay cell.The detectable terahertz frequency range of the detection system was 0.90 Thz–1.83 THz.Besides,the effects of pump energy and effective gain length on the detection sensitivity were studied in experiment.The results showed that higher pump energy and longer effective gain length are helpful for improving the detection sensitivity of parametric up-conversion detector.展开更多
The up-conversion luminescence tuning of rare-earth ions is an important research topic for understanding luminescence mechanisms and promoting related applications. In this paper, we experimentally study the up-conve...The up-conversion luminescence tuning of rare-earth ions is an important research topic for understanding luminescence mechanisms and promoting related applications. In this paper, we experimentally study the up-conversion luminescence tuning of Er3+-doped ceramic glass excited by the unshaped, V-shaped and cosine-shaped femtosecond laser field with different laser powers. The results show that green and red up-conversion luminescence can be effectively tuned by varying the power or spectral phase of the femtosecond laser field. We further analyze the up-conversion luminescence tuning mechanism by considering different excitation processes, including single-photon absorption(SPA), two-photon absorption(TPA), excited state absorption(ESA), and energy transfer up-conversion(ETU). The relative weight of TPA in the whole excitation process can increase with the increase of the laser power, thereby enhancing the intensity ratio between green and red luminescence(I547/I656). However, the second ETU(ETU2) process can generate red luminescence and reduce the green and red luminescence intensity ratio I547/I656, while the third ESA(ESA3) process can produce green luminescence and enhance its control efficiency. Moreover, the up-conversion luminescence tuning mechanism is further validated by observing the up-conversion luminescence intensity, depending on the laser power and the down-conversion luminescence spectrum under the excitation of 400-nm femtosecond laser pulse. These studies can present a clear physical picture that enables us to understand the up-conversion luminescence tuning mechanism in rare-earth ions, and can also provide an opportunity to tune up-conversion luminescence to promote its related applications.展开更多
A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulse...A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.展开更多
We report on the experimental study of the visible and ultraviolet (UV) fluorescence emission in a (1% molar) Thulium (Tm+3)-doped Zirconium fluoride glass sample. From red at 650 nm, blue (453 & 480 nm) and UV at...We report on the experimental study of the visible and ultraviolet (UV) fluorescence emission in a (1% molar) Thulium (Tm+3)-doped Zirconium fluoride glass sample. From red at 650 nm, blue (453 & 480 nm) and UV at 365 & 284 nm, have been observed under excitation of a Nd:YAG laser at 1.064 μm. The responsible up-conversion mechanisms are investigated based on experimental data. The related problem of photo-degradation associated with formation of color centers is also addressed.展开更多
We theoretically demonstrate a model which can be used to analyze frequency up-conversion of a laser wavelength by using thermal population. The proposed model uses a rate equation model of ytterbium-doped fiber with ...We theoretically demonstrate a model which can be used to analyze frequency up-conversion of a laser wavelength by using thermal population. The proposed model uses a rate equation model of ytterbium-doped fiber with thermal population effect. The rate and power propagation equations are set up and numerically analyzed to elucidate the dependence of frequency up-conversion efficiency and thermal-optical conversion efficiency on ambient thermal power. The analytical techniques and numerical results show that using pump laser at 1 000 nm,the wavelength can be converted into 900 nm with an up-conversion quantum efficiency of about 99.97% and a cooling efficiency of about 11.1%. This theoretical model is a promising candidate for vast applications in energyefficient laser and energy-utilizing field.展开更多
The linker defect engineering for MOFs is a viable strategy that usually can effectively augment conductivity to further promote charge carrier separation,which is the most excellent conductivity of preserved metal cl...The linker defect engineering for MOFs is a viable strategy that usually can effectively augment conductivity to further promote charge carrier separation,which is the most excellent conductivity of preserved metal clusters.However,the partially missing photosensitive linker often leads to the diminished light utilization efficiency.As we know,in the linker defect engineering,addressing the lack of photosensitivity while maintaining outstanding conductivity is still in its infancy.In this essay,the linkerdefective NH_(2)-MIL-125 was obtained by adding the glacial acetic acid regulator,subsequently,the excellent light-responsive Pt/CQDs with up-conversion effect was in-situ encapsulated into the enlarged pore space of linker-defective NH_(2)-MIL-125.It is excited that the fabricated dual-functional composite ideally integrates photosensitivity and conductivity for photocatalytic hydrogen evolution and NO elimination.The optimal Pt/CQDs@NM-125-4 exhibited very superior photocatalytic hydrogen evolution(28.75mmol/g),it was 11.63 times as that of the initial NH_(2)-MIL-125(2.47 mmol/g)and 1.4 times as that of the defective NM-125-4(20.46 mmol/g).In addition,the excellent photocatalytic NO removal efficiency was 52.12%for Pt/CQDs@NM-125-4,whereas the original NH_(2)-MIL-125 only reached 30%and the defective NM-125-4 achieved 44.96%.The corresponding optical and electrical characterization based on UV-vis,up-conversion photoluminescence(UCPL),and electrochemical impedance spectroscopy(EIS)etc.demonstrated the defect engineering accelerates the charge carriers transfer via enhancing conductivity,and the in-situ confined up-conversion Pt/CQDs promote the visible light response.Our work presents a feasible avenue to integrate photosensitivity and conductivity via in-situ fabricating excellent lightresponsive Pt/CQDs within linker-defective NH_(2)-MIL-125 for further significantly boosting photocatalytic performance.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
A non-polar organic dye, E, E-1, 4-bis[4＇-（N,N-dibutylamino）styryl]-2,5-dimethoxybenzene （DBASDMB）, has been synthesized and characterized, and its structure has been determined. Pumped with a 200fs pulse this dy...A non-polar organic dye, E, E-1, 4-bis[4＇-（N,N-dibutylamino）styryl]-2,5-dimethoxybenzene （DBASDMB）, has been synthesized and characterized, and its structure has been determined. Pumped with a 200fs pulse this dye showed the up-conversion laser properties. The influences of various organic solvents and different pumping wavelength on the laser properties have been demonstrated.展开更多
For developing and utilizing near-infrared(NIR)energy in sunlight,NaYF4:Yb,Tm(NYFYT)up-conversion Iuminescent powder was combined with Ag_(3)PO_(4)(AP)and Ag_(3)PO_(4)/Pt nanoparticles(AP/PtNPs)as a photocatalyst.Driv...For developing and utilizing near-infrared(NIR)energy in sunlight,NaYF4:Yb,Tm(NYFYT)up-conversion Iuminescent powder was combined with Ag_(3)PO_(4)(AP)and Ag_(3)PO_(4)/Pt nanoparticles(AP/PtNPs)as a photocatalyst.Driven by NIR light,NYFYT produces up-conversion emission at 348,364,453 and 478 nm,effectively stimulating the photocatalytic degradation performance of AP and AP/PtNPs,Under xenon lamp irradiation,the apparent rate constants(k)for Ag_(3)PO_(4)/Pt nanoparticles-NaYF4:Yb,Tm(AP/PtNPs-NYFYT)in photocatalytic degradation of rhodamine B(Rh B)and phenol are 5.51 and 12.82 times higher than those of AP and 1.90 and 2.37 times higher than those of AP-NYFYT-50 wt%,respectively.In addition,under 980nm laser irradiation,rate constants are 3.26 and 4.16 times higher than those of AP-NYFYT-50 wt%,respectively.These results indicate that the combination of NYFYT and AP expands the absorption range of the composite photocatalyst and facilitates the NIR-driven photocatalytic process.The introduction of PtNPs effectively prevents the electron-hole recombination and the reduction of Ag+,accelerating the redox reaction and promoting the photocatalytic activity and stability of AP.展开更多
A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser p...A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HMASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 8.4% which is higher than that of trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI)(1) at the same pump level.展开更多
Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion...Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion luminescent properties of HMASPS and HEASPS1 in three different microenvironments were studied.展开更多
A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used ...A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the upconversion mixer to improve its gain and increase the voltage swing. The measurement results show that the input P1dB achieves -3.6dBm, the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.展开更多
Rare earth ions doped oxyfluoride glass with composition of 28SiO2·22AlO1.5·40PbF2·10PbO·（4.8-x） GdFy0.1NdF3.xYbF3·0.1TmF3 （x=-0, 0.1, 0.2, 0.5, 1, 2, 3, 4 and 4.8） in molar ratio was deve...Rare earth ions doped oxyfluoride glass with composition of 28SiO2·22AlO1.5·40PbF2·10PbO·（4.8-x） GdFy0.1NdF3.xYbF3·0.1TmF3 （x=-0, 0.1, 0.2, 0.5, 1, 2, 3, 4 and 4.8） in molar ratio was developed. When the oxyfluoride glasses were heat-treated at the first crystallization temperature, the glasses gave transparent glass-ceramics in which rare earth containing fluorite-type nanocrystals of about 17.2 nm in diameter uniformly precipitated in the glass matrix. Compared with the glasses before heat treatment, the glass-ceramics exhibited very strong blue up-conversion luminescence under 800 nm light excitation. Rare earth containing nanocrystals were also space selectively precipitated upon laser irradiation in an oxyfluoride glass, the size of precipitated nanocrystals could be controlled by laser power and scan speed. The intensity of the blue up-conversion luminescence was strongly dependent on the precipitation of β-PbF2 nanocrystal and the YbF3 concentration. The reasons for the highly efficient Tm^3＋ up-conversion luminescence after laser irradiation were discussed.展开更多
The possibility of ttming between red, green and broadband white color of up-conversion was demonstrated in thermally 450 ℃ treated Yb/Er co-doped nano NaYF4 phosphor. The color variability was studied by means of po...The possibility of ttming between red, green and broadband white color of up-conversion was demonstrated in thermally 450 ℃ treated Yb/Er co-doped nano NaYF4 phosphor. The color variability was studied by means of power dependence of luminescence, which exhibited unusual behavior. Large hysteresis, as well as discrepancy from a power law indicated the important role the increased heating played during the up-conversion in nano-sized materials.展开更多
Herein,we reported Er^3+/Yb^3+co-doped CaLaAl3O7 up-conversion phosphors synthesized via solid state reaction,which was further explored as a new optical thermometry.The luminescent properties of Er^3+or Er^3+/Yb^3+do...Herein,we reported Er^3+/Yb^3+co-doped CaLaAl3O7 up-conversion phosphors synthesized via solid state reaction,which was further explored as a new optical thermometry.The luminescent properties of Er^3+or Er^3+/Yb^3+doped CaLaAl3O7 phosphor was studied in detail.The two-photon process for the green emissions of Er^3+were confirmed by the power-dependent luminescence.The up-conversion optical temperature sensing performances of the Er^3+/Yb^3+-codoped CaLaAl3O7 phosphor were investigated based on the FIR technique.The maximum sensitivity of this phosphor can reach about 0.00345 K-1 at 453 K,which reveals this phosphor can be a promising candidate for optical thermometry devices.展开更多
A novel synthesis method for hexagonal （]3）ophase NaYF4：Er nano-crystals （NCs） which showed up-conversion （UC） from infrared to visible spectral region was developed. The NaYF4：Er NCs were synthesized in oleie...A novel synthesis method for hexagonal （]3）ophase NaYF4：Er nano-crystals （NCs） which showed up-conversion （UC） from infrared to visible spectral region was developed. The NaYF4：Er NCs were synthesized in oleie acid （OA） and 1-0ctadeeene （ODE） with Y2（COa）3＇xH20, Er2（COa）3xH20, Na2CO3 and NH4F as precursors. This proposed method was simple and less toxic compared with generally used method so far. The XRD results showed that the molar ratio of OA/ODE and the temperature were key factors for phase control ofNaYF4：Er NCs. The UC emission spectra were obtained with the emission wavelength at about 980 nm （4111/2--4115/2）, 800 nm （41912--415/2）, 660 nm （4F912--4115/2） and 540 nm （453/2----4115/2） from Er3＋ ions, by excitation wavelength of 1550 nm. The slope values, n, in the pump-power dependence, showed that the emission at 980 and 800 um were generated by 2-step UC and at 660 nm and 540 um were 3-step UC. The optical process for the UC excitation was discussed.展开更多
Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light c...Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light carrying orbital angular momentum(OAM) from a difference frequency generation process and perform up-conversion on it via sum frequency conversion in a bulk quasi-phase-matching crystal. The maximum quantum conversion efficiencies from MIR to visible are 34.0%, 10.4%, and 3.5% for light with topological charges of 0, 1, and 2, respectively, achieved by utilizing an optimized strong pump light. We also verify the OAM conservation with a specially designed interferometer, and the results agree well with the numerical simulations. Our study opens up the possibilities for generating, manipulating, and detecting MIR light that carries OAM, and will have great potential for optical communications and remote sensing in the MIR regime.展开更多
We propose a simple pump-coupling-seed scheme to examine the optical X^2Σg^+–A^2Πu coupling in N2^+ lasing. We produce the N2^+ lasing at 391 nm, corresponding to the B^2Σu^+(v = 0)–X^2Σg+(v = 0) transition, by ...We propose a simple pump-coupling-seed scheme to examine the optical X^2Σg^+–A^2Πu coupling in N2^+ lasing. We produce the N2^+ lasing at 391 nm, corresponding to the B^2Σu^+(v = 0)–X^2Σg+(v = 0) transition, by externally seeding the N^2+ gain medium prepared by irradiation of N2 with an intense pump pulse. We then adopt a weak coupling pulse in between the pump and seed pulses, and show that the intensity of the 391-nm lasing can be efficiently modulated by varying the polarization direction of the coupling pulse with respect to that of the pump pulse. It is found that when the polarization directions of the pump and coupling pulses are perpendicular, the 391-nm lasing intensity is more sensitive to the coupling laser energy, which reflects the inherent nature of the perpendicular X^2+Σg^–A^2Πu transition.展开更多
Er3 +/Yb3 +-codoped oxyfluoride crystallite glass was prepared with melting technique. The compositions and the melting temperature and the annealing temperature of the rare earth-doped crystallite glass were studied ...Er3 +/Yb3 +-codoped oxyfluoride crystallite glass was prepared with melting technique. The compositions and the melting temperature and the annealing temperature of the rare earth-doped crystallite glass were studied in detail. The emission spectra of samples were measured with the Hitachi F-4500 fluorescent photometer pumped by 980 nm wavelength laser. The up-conversion luminescence mechanism was illuminated on the view of the photophysics. By measuring the relationship between luminescent intensity and pump power, it is confirmed that the emission peaks at 550 nm belong to two-photon process, while that at 665 nm belongs to three-photon process. Moreover, the distributions of crystalline were determined by SEM.展开更多
The up-conversion of Er3＋/yb3＋ co-doped transparent glass-ceramics 50SiO2-10A1F3-5TiO2-30BaF2-4LaF3-0.5ErF3-0.5YbF3 containing Ba2LaF7 nanocrystals under the changing of heat treatment temperature and time were inve...The up-conversion of Er3＋/yb3＋ co-doped transparent glass-ceramics 50SiO2-10A1F3-5TiO2-30BaF2-4LaF3-0.5ErF3-0.5YbF3 containing Ba2LaF7 nanocrystals under the changing of heat treatment temperature and time were investigated. The Ba2LaF7 nanocrystals precipitated from the glass matrix was confirmed by X-ray diffraction （XRD）. The structural investigation carried out by XRD and trans- mission electron microscopy （TEM） evidenced the formation of cubic Ba2LaF7 nanocrystals with crystal size of about 14 nm. Comparing with the samples before heat treatment, the high efficiency up-conversion emission of Er3＋/Yb3＋ co-doped samples was observed in the glass-ceramics under 980 nm laser diode excitation. The increase in red emission intensity bands was stronger than the green bands when the crystal size increased. The mechanism for the up-conversion process in the glass-ceramics and the reasons for the increase of Er3＋/yb3＋ co-doped up-conversion intensity after heat treatment were discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U1837202,61775160,61771332,62011540006,and 62175182)。
文摘A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric upconversion.A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the upconversion from terahertz wave to NIR laser was realized in a lithium niobate crystal.The minimum detectable terahertz energy of 9 p J was realized with the detection dynamic range of 54 d B,which was three orders of magnitude higher than that of commercial Golay cell.The detectable terahertz frequency range of the detection system was 0.90 Thz–1.83 THz.Besides,the effects of pump energy and effective gain length on the detection sensitivity were studied in experiment.The results showed that higher pump energy and longer effective gain length are helpful for improving the detection sensitivity of parametric up-conversion detector.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51132004,11474096,11604199,U1704145,and 11747101)the Fund from the Science and Technology Commission of Shanghai Municipality,China(Grant No.14JC1401500)+1 种基金the Henan Provincial Natural Science Foundation,China(Grant No.182102210117)the Higher Educational Key Program of Henan Province of China(Gant Nos.17A140025 and 16A140030)
文摘The up-conversion luminescence tuning of rare-earth ions is an important research topic for understanding luminescence mechanisms and promoting related applications. In this paper, we experimentally study the up-conversion luminescence tuning of Er3+-doped ceramic glass excited by the unshaped, V-shaped and cosine-shaped femtosecond laser field with different laser powers. The results show that green and red up-conversion luminescence can be effectively tuned by varying the power or spectral phase of the femtosecond laser field. We further analyze the up-conversion luminescence tuning mechanism by considering different excitation processes, including single-photon absorption(SPA), two-photon absorption(TPA), excited state absorption(ESA), and energy transfer up-conversion(ETU). The relative weight of TPA in the whole excitation process can increase with the increase of the laser power, thereby enhancing the intensity ratio between green and red luminescence(I547/I656). However, the second ETU(ETU2) process can generate red luminescence and reduce the green and red luminescence intensity ratio I547/I656, while the third ESA(ESA3) process can produce green luminescence and enhance its control efficiency. Moreover, the up-conversion luminescence tuning mechanism is further validated by observing the up-conversion luminescence intensity, depending on the laser power and the down-conversion luminescence spectrum under the excitation of 400-nm femtosecond laser pulse. These studies can present a clear physical picture that enables us to understand the up-conversion luminescence tuning mechanism in rare-earth ions, and can also provide an opportunity to tune up-conversion luminescence to promote its related applications.
文摘A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.
文摘We report on the experimental study of the visible and ultraviolet (UV) fluorescence emission in a (1% molar) Thulium (Tm+3)-doped Zirconium fluoride glass sample. From red at 650 nm, blue (453 & 480 nm) and UV at 365 & 284 nm, have been observed under excitation of a Nd:YAG laser at 1.064 μm. The responsible up-conversion mechanisms are investigated based on experimental data. The related problem of photo-degradation associated with formation of color centers is also addressed.
基金the National Natural Science Foundation of China(Nos.60377023 and 60672017)the Program for New Century Excellent Talents in Universities(NCET)the Shanghai Optical Science and Technology Project(No.05DZ22009)
文摘We theoretically demonstrate a model which can be used to analyze frequency up-conversion of a laser wavelength by using thermal population. The proposed model uses a rate equation model of ytterbium-doped fiber with thermal population effect. The rate and power propagation equations are set up and numerically analyzed to elucidate the dependence of frequency up-conversion efficiency and thermal-optical conversion efficiency on ambient thermal power. The analytical techniques and numerical results show that using pump laser at 1 000 nm,the wavelength can be converted into 900 nm with an up-conversion quantum efficiency of about 99.97% and a cooling efficiency of about 11.1%. This theoretical model is a promising candidate for vast applications in energyefficient laser and energy-utilizing field.
基金supported by the National Natural Science Foundation of China(Nos.22001026,22171233,22201193)Sichuan Science and Technology Program(No.2023NSFSC0109)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Hundred Talent Program of Sichuan University(No.YJ2021158)。
文摘The linker defect engineering for MOFs is a viable strategy that usually can effectively augment conductivity to further promote charge carrier separation,which is the most excellent conductivity of preserved metal clusters.However,the partially missing photosensitive linker often leads to the diminished light utilization efficiency.As we know,in the linker defect engineering,addressing the lack of photosensitivity while maintaining outstanding conductivity is still in its infancy.In this essay,the linkerdefective NH_(2)-MIL-125 was obtained by adding the glacial acetic acid regulator,subsequently,the excellent light-responsive Pt/CQDs with up-conversion effect was in-situ encapsulated into the enlarged pore space of linker-defective NH_(2)-MIL-125.It is excited that the fabricated dual-functional composite ideally integrates photosensitivity and conductivity for photocatalytic hydrogen evolution and NO elimination.The optimal Pt/CQDs@NM-125-4 exhibited very superior photocatalytic hydrogen evolution(28.75mmol/g),it was 11.63 times as that of the initial NH_(2)-MIL-125(2.47 mmol/g)and 1.4 times as that of the defective NM-125-4(20.46 mmol/g).In addition,the excellent photocatalytic NO removal efficiency was 52.12%for Pt/CQDs@NM-125-4,whereas the original NH_(2)-MIL-125 only reached 30%and the defective NM-125-4 achieved 44.96%.The corresponding optical and electrical characterization based on UV-vis,up-conversion photoluminescence(UCPL),and electrochemical impedance spectroscopy(EIS)etc.demonstrated the defect engineering accelerates the charge carriers transfer via enhancing conductivity,and the in-situ confined up-conversion Pt/CQDs promote the visible light response.Our work presents a feasible avenue to integrate photosensitivity and conductivity via in-situ fabricating excellent lightresponsive Pt/CQDs within linker-defective NH_(2)-MIL-125 for further significantly boosting photocatalytic performance.
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.
基金the State Key Program of China,the National Natural Science Foundation of China(50173015)NSFC/RGC(50218001)+1 种基金the Foundation for University Key Teacher by the Ministry of EducationChina Postdoctoral Foundation.
文摘A non-polar organic dye, E, E-1, 4-bis[4＇-（N,N-dibutylamino）styryl]-2,5-dimethoxybenzene （DBASDMB）, has been synthesized and characterized, and its structure has been determined. Pumped with a 200fs pulse this dye showed the up-conversion laser properties. The influences of various organic solvents and different pumping wavelength on the laser properties have been demonstrated.
基金Project supported by Hebei Province High-level Talent(Postdoctor)Funding Project(B2022003025)。
文摘For developing and utilizing near-infrared(NIR)energy in sunlight,NaYF4:Yb,Tm(NYFYT)up-conversion Iuminescent powder was combined with Ag_(3)PO_(4)(AP)and Ag_(3)PO_(4)/Pt nanoparticles(AP/PtNPs)as a photocatalyst.Driven by NIR light,NYFYT produces up-conversion emission at 348,364,453 and 478 nm,effectively stimulating the photocatalytic degradation performance of AP and AP/PtNPs,Under xenon lamp irradiation,the apparent rate constants(k)for Ag_(3)PO_(4)/Pt nanoparticles-NaYF4:Yb,Tm(AP/PtNPs-NYFYT)in photocatalytic degradation of rhodamine B(Rh B)and phenol are 5.51 and 12.82 times higher than those of AP and 1.90 and 2.37 times higher than those of AP-NYFYT-50 wt%,respectively.In addition,under 980nm laser irradiation,rate constants are 3.26 and 4.16 times higher than those of AP-NYFYT-50 wt%,respectively.These results indicate that the combination of NYFYT and AP expands the absorption range of the composite photocatalyst and facilitates the NIR-driven photocatalytic process.The introduction of PtNPs effectively prevents the electron-hole recombination and the reduction of Ag+,accelerating the redox reaction and promoting the photocatalytic activity and stability of AP.
基金This tvork was supported by the grant for state key program of China by the National NaturalScience Foundation of China, al
文摘A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HMASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 8.4% which is higher than that of trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI)(1) at the same pump level.
基金This work was supported by the grant for State Key Program of China.
文摘Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion luminescent properties of HMASPS and HEASPS1 in three different microenvironments were studied.
文摘A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the upconversion mixer to improve its gain and increase the voltage swing. The measurement results show that the input P1dB achieves -3.6dBm, the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.
基金supported by the National Natural Science Foundation of China (50572029) Natural Science Foundation Project of Yunnan Province (2007E036M)
文摘Rare earth ions doped oxyfluoride glass with composition of 28SiO2·22AlO1.5·40PbF2·10PbO·（4.8-x） GdFy0.1NdF3.xYbF3·0.1TmF3 （x=-0, 0.1, 0.2, 0.5, 1, 2, 3, 4 and 4.8） in molar ratio was developed. When the oxyfluoride glasses were heat-treated at the first crystallization temperature, the glasses gave transparent glass-ceramics in which rare earth containing fluorite-type nanocrystals of about 17.2 nm in diameter uniformly precipitated in the glass matrix. Compared with the glasses before heat treatment, the glass-ceramics exhibited very strong blue up-conversion luminescence under 800 nm light excitation. Rare earth containing nanocrystals were also space selectively precipitated upon laser irradiation in an oxyfluoride glass, the size of precipitated nanocrystals could be controlled by laser power and scan speed. The intensity of the blue up-conversion luminescence was strongly dependent on the precipitation of β-PbF2 nanocrystal and the YbF3 concentration. The reasons for the highly efficient Tm^3＋ up-conversion luminescence after laser irradiation were discussed.
基金Project supported by Polish National Science Centre (N N507 584938,N N507599038)the Foundation for Polish Science
文摘The possibility of ttming between red, green and broadband white color of up-conversion was demonstrated in thermally 450 ℃ treated Yb/Er co-doped nano NaYF4 phosphor. The color variability was studied by means of power dependence of luminescence, which exhibited unusual behavior. Large hysteresis, as well as discrepancy from a power law indicated the important role the increased heating played during the up-conversion in nano-sized materials.
基金Project supported by National Natural Science Foundation of China(51802069,61205180)the First Batch of Young Talent Support Plan of Hebei ProvinceGraduate Student Innovation Project of Hebei University(hbu2018ss62)
文摘Herein,we reported Er^3+/Yb^3+co-doped CaLaAl3O7 up-conversion phosphors synthesized via solid state reaction,which was further explored as a new optical thermometry.The luminescent properties of Er^3+or Er^3+/Yb^3+doped CaLaAl3O7 phosphor was studied in detail.The two-photon process for the green emissions of Er^3+were confirmed by the power-dependent luminescence.The up-conversion optical temperature sensing performances of the Er^3+/Yb^3+-codoped CaLaAl3O7 phosphor were investigated based on the FIR technique.The maximum sensitivity of this phosphor can reach about 0.00345 K-1 at 453 K,which reveals this phosphor can be a promising candidate for optical thermometry devices.
文摘A novel synthesis method for hexagonal （]3）ophase NaYF4：Er nano-crystals （NCs） which showed up-conversion （UC） from infrared to visible spectral region was developed. The NaYF4：Er NCs were synthesized in oleie acid （OA） and 1-0ctadeeene （ODE） with Y2（COa）3＇xH20, Er2（COa）3xH20, Na2CO3 and NH4F as precursors. This proposed method was simple and less toxic compared with generally used method so far. The XRD results showed that the molar ratio of OA/ODE and the temperature were key factors for phase control ofNaYF4：Er NCs. The UC emission spectra were obtained with the emission wavelength at about 980 nm （4111/2--4115/2）, 800 nm （41912--415/2）, 660 nm （4F912--4115/2） and 540 nm （453/2----4115/2） from Er3＋ ions, by excitation wavelength of 1550 nm. The slope values, n, in the pump-power dependence, showed that the emission at 980 and 800 um were generated by 2-step UC and at 660 nm and 540 um were 3-step UC. The optical process for the UC excitation was discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92065101 and 11934013)Anhui Initiative In Quantum Information Technologies(Grant No.AHY020200)。
文摘Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light carrying orbital angular momentum(OAM) from a difference frequency generation process and perform up-conversion on it via sum frequency conversion in a bulk quasi-phase-matching crystal. The maximum quantum conversion efficiencies from MIR to visible are 34.0%, 10.4%, and 3.5% for light with topological charges of 0, 1, and 2, respectively, achieved by utilizing an optimized strong pump light. We also verify the OAM conservation with a specially designed interferometer, and the results agree well with the numerical simulations. Our study opens up the possibilities for generating, manipulating, and detecting MIR light that carries OAM, and will have great potential for optical communications and remote sensing in the MIR regime.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61625501,11904121,and 61427816)the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM),China+1 种基金the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT),China(Grant No.2017TD-21)Fundamental Research Funds for the Central Universities of China
文摘We propose a simple pump-coupling-seed scheme to examine the optical X^2Σg^+–A^2Πu coupling in N2^+ lasing. We produce the N2^+ lasing at 391 nm, corresponding to the B^2Σu^+(v = 0)–X^2Σg+(v = 0) transition, by externally seeding the N^2+ gain medium prepared by irradiation of N2 with an intense pump pulse. We then adopt a weak coupling pulse in between the pump and seed pulses, and show that the intensity of the 391-nm lasing can be efficiently modulated by varying the polarization direction of the coupling pulse with respect to that of the pump pulse. It is found that when the polarization directions of the pump and coupling pulses are perpendicular, the 391-nm lasing intensity is more sensitive to the coupling laser energy, which reflects the inherent nature of the perpendicular X^2+Σg^–A^2Πu transition.
文摘Er3 +/Yb3 +-codoped oxyfluoride crystallite glass was prepared with melting technique. The compositions and the melting temperature and the annealing temperature of the rare earth-doped crystallite glass were studied in detail. The emission spectra of samples were measured with the Hitachi F-4500 fluorescent photometer pumped by 980 nm wavelength laser. The up-conversion luminescence mechanism was illuminated on the view of the photophysics. By measuring the relationship between luminescent intensity and pump power, it is confirmed that the emission peaks at 550 nm belong to two-photon process, while that at 665 nm belongs to three-photon process. Moreover, the distributions of crystalline were determined by SEM.
基金Project supported by National Natural Science Foundation of China(51272097,61265004,51002068)973 Program(2011CB211708)+4 种基金Society Development Foundation of Yunnan Province(2009CC009)Natural Science Foundation of Yunnan Province(2010ZC038)Postdoctoral Science Foundation of China(20110491759)Education Department Foundation of Yunnan Province(2011Y348)Foundation of Yunnan Province(2012FD009)
文摘The up-conversion of Er3＋/yb3＋ co-doped transparent glass-ceramics 50SiO2-10A1F3-5TiO2-30BaF2-4LaF3-0.5ErF3-0.5YbF3 containing Ba2LaF7 nanocrystals under the changing of heat treatment temperature and time were investigated. The Ba2LaF7 nanocrystals precipitated from the glass matrix was confirmed by X-ray diffraction （XRD）. The structural investigation carried out by XRD and trans- mission electron microscopy （TEM） evidenced the formation of cubic Ba2LaF7 nanocrystals with crystal size of about 14 nm. Comparing with the samples before heat treatment, the high efficiency up-conversion emission of Er3＋/Yb3＋ co-doped samples was observed in the glass-ceramics under 980 nm laser diode excitation. The increase in red emission intensity bands was stronger than the green bands when the crystal size increased. The mechanism for the up-conversion process in the glass-ceramics and the reasons for the increase of Er3＋/yb3＋ co-doped up-conversion intensity after heat treatment were discussed.
