最新刊期
卷 20 ， 期 4 ， 1999
- 摘要：The hypergeometric state is a one-parameter generalization of the binomial state. Itcan reduce to the binomial state in certain limit. The interaction of the binomial statewith two-level atoms in cavities has been studied in detail in the literature. In this article, we study the interaction of the hypergeometric state with two-level atoms. We usethe intensity-dependent Jaynes-Cummings model and the interaction is of intensity-dependent type. The dynamics of atomic population inversion and second order correlationfunction of the field were studied in detail. The collapse and revival phenomena arefound when the initial field state is the hypergeometric state. The field can show antibunching effects. The antibunching effect is better than that of the binomial state.关键词：hypergeometric states;J-C moded;dynamical evolution112|81|0更新时间：2020-08-11
- 摘要：In this work, we have a designation and preparation of MFT glasses for upconversion, the glasses consisted of TeO2 and fluoride: PbF2, AIF3, BaF2, NaF and the impurity Tm2O3. In this glassy system the oxide improve forming ability, the fluoridesimprove the microscopic environment around RE ions in glasses. In this glass host thecontent of Tm2O3, achieves to 4% molar and crystallization not occurred. The absorptionspectra of the glass containing Tm3+ of 0.2% molar were measured and the transitionsfrom ground state 3H6 to the different excited state 1D2, 1G4, 1F3(3F2) and 3H4 were observed. The absorption band of 3F3(3F2) is suiting for upconversion under red light excitation. In order to understand the dependence of excited wavelength on upconversionfluorescence intensity, the relationship between upconversion fluorescence intensity andexcited wavelength were measured when the wavelength is various from 640nm to 670nm. We find that the excitation at 650urn is efficient for upconversion of transitionfrom 1G4 to 3H6 and 670nm is efficient from 1D2 to 3H4. The variation of upconversionluminescence intensity with concentration of Tm3+ in MFT glasses under 650urn excitation was observed, and the quenching concentration is 0.6% molar was obtained, thequenching concentration of Tm3+ was higher about 3 times than in other glassesobserved by numerous author. At last, we have a study on the upconversion fluorescence slope efficiency, the relationship between upconversion luminescence intensity andexcited power density was determined, and the 2-photon upconversion process wasassigned by fitting experimental data.关键词：upconversion;telluride glass105|68|1更新时间：2020-08-11
- 摘要：Demonstrations of upconversion pumped by solid state lasers have enhanced the interest in excitation mechanisms that result in emission with wavelengths shorter thanthat of the pump light. Efficient upconversion is possible in rare earth-doped materials with metastable, intermediate levels that can act as a storage reservoir for the pump energy. Subsequent emission from higher lying state, can be induced by excited stateabsorption of pump photons, or by energy transfer processes. The aim of this work isgive a method for study on the optical gain of upconversion luminescence. We have astudy for optical gain of upconversion of Tm3+ in MFT glass under 650nm excitation,and in our experimental conditions the gain coefficient of the blue upconversion luminescence of Tm3+ were obtained by ASE techniques.In this paper, the preparation of new glass material MFT (components with 50TeO2-19.7PbF2-10AIF3-10BaF3-10BaF2-0.3Tm2O3) has been reported. Two blue upconversion luminescence from 1D2→3H4(453nm) and 1G4→3H6(476nm) transitions of Tm3+-doped in MFT glass under 650nm excitation has been observed. The relationshipbetween upconversion luminescence intensity and the intensity of excitation light hasbeen discussed. The optical gains of blue upconversion of Tm3+ in MFT were measuredusing ASE technique for the first time. The values of optical gain coefficient is BD=1.79±0.16mm-1 and BG=1.65±0.23mm-1 for 1D2→3H4 and 1G4→3H6 emissions respectively.关键词：optical gain;upconversion87|71|0更新时间：2020-08-11
- 摘要：In this work, a glass host doped with Tm3+ and Yb3+ for IR to visible upconversionwas designed; and the Raman scattering method was used to analysis of structure properties, and the process and properties of blue and red upconversion under 970urn LDexcitation was discussed.The Multi-Fluoride-Telluride glass material co-doped with Tm3+ and Yb3+ havebeen designed and prepared by melting method in muffle furnace at 800℃. The glasssample components are 50TeO2-14.9PbF2-10AIF3-10BaF2-10BaF2-10NaF-0.1Tm2O3-5Yb2O3.The Raman shift spectrum was measured with JY-T 800 Raman spectrometer under 488nm of Ar+ laser. We observe the maximum phonon energy is 755cm-1 in the studiedglass. Some vibrative models with narrow line width in Raman scattering spectra showthat the micro-crystals presented in the glass sample. The spectra of upconversion luminescence of Tm3+ by Yb3+ sensitization in the glass sample were measured with Shimadzu RF-520 fluorescence spectrometer. The very intense blue upconversion luminescence was observed by naked eyes under 970nm LD excitation. We have be prove thatthe blue upconversion luminescence from 1G4-3H6 transition of Tm3+, with wavelengthof 476.6nm. The wavelength of the red upconversion luminescence originated from 3F3→3H6 and 1G4→3H4 transitions are of Tm3+ 699urn and 663nm, respectively. The bothred upconversion emissions are weaker versus blue upconversion luminescence. A studyon relationship between the LD working current and intensity of red and blue upconversion luminescence was confirmed. The relationship directs that, the blue upconversionprocess needs three photons, and the red one needs two photons.关键词：upconversion;MFT glass81|81|2更新时间：2020-08-11
- 摘要：Raman scattering was used to investigate the microcrystal region in glass ceramics PbF2+WO3+GeO2 and PbF2+WO3+GeO2 doped with YbF3 and TmF3. The spectra obtained show that this micro-crystal region in the PbF2+WO3+GeO2 is with the composition of PbF2:Yb3+, Tm3+, in which the Yb3+and Tm3+ ions are substituted for Pb2+ resulting in some charged centers located at these impurities. These charged centers induce a local electric field which brings about:(1) some new Raman effects in addition to the Raman effects induced by the modulation of polarizability from vibrations of micro-crystal lattice, and (2) the consistency of all directions of the symmetry axes of microcrystal in PbF2+WO3+GeO2.关键词：upconversion;glass ceramics;local action84|76|0更新时间：2020-08-11
- 摘要：The phosphor BaAl12O19: Mn was synthesized by solid state reaction at 1300℃ under the existence of flux. Its XRD diagram showed the intensity increased with the presence of the flux, the intensity of different crystal planes W.. changed with the flux,for example, crystal planes (102), (107), (114) and (205) became stronger, while crystal planes(0010) and (304) became weak. These results indicate that the flux not only helped to crystallize the host but also affected on growth of different crystal planes.The UV excitation spectrum consists of three bands peaking at 279urn, 360.5nm,384.6nm, which are due to the 6A1→2A2(4F), 6A1→4E(4D), 6A1→4T2 (4D) of Mn2+ transitions, respectively. Its photoluminescence spectra showed there is a stronger emission band peaking at 514nm and a weak emission band peaking at 450nm. The former band is assighed to Mn2+-emission, and the latter band may be origin from the host. The emission of Mn2+ ions indicated that Mn2+ ions occupy crystallographic site of Al in tetrahedral. The experimental result also indicated that the influence of different flux on the luminescent intensity of the phosphor BaAl12O19: Mn varied: H,BO, decreased its luminescence, AIF3 improved a little and BaF2 improved greatly. The VUV excitation spectrum consists of the bands peaking around 150urn and 195urn that correspond to the host absorption and the 3d5→3d4s1 Mn2+ transition. This result reveals that there is an high efficient energy transfer from the host to the activator. The strong absorption at about 150nm also indicates that the phosphor BaAl12O19: Mn can act as a better candidate of PDP phosphors.83|64|5更新时间：2020-08-11
- 摘要：In this paper, different concentrations of Gd2O3 have been doped in the preparation of red phosphors Y2O2S: Eu3+. It is discovered that the emission intensity is enhanced 5% and the voltage character (Relation between emission intensity and excitation voltage) is improved by doping proper concentration of Gd2O3 under the emission color, particle size and the properties of physics and chemistry are in keep with the request. The enhancement origins of emission intensity are discussed and analyzed preliminarily. It is lacely that the abnormal change of crystal checks that is led by the substitution of large rradius Eu3+ ion for smaller radius Y3+ ion is improved by substitution of Gd3+ ion for Y3+ ion, the process of no radiation and crystal defect which lose energy are cut down.The improvement of Eu3+ ion's crystal field condition give rise to enhance of the main emission peak 626nm, 616nm (to be attributed to 5Do→7F2) and 704nm (to be attributedto 5Do→7F4) in the CR spectra of Y2O2S: Eu3+.105|83|4更新时间：2020-08-11
- 摘要：The full-color electroluminescence (EL) display has not yet been commercialized due to lack of good blue or white phosphors. The traditional EL host matrices, such as Ⅱ-Ⅳ sulphides or ternary compounds, have a difficulty of charge compensation when they are doped with rare-earth ions, which will lead unexpected defect energy levels and.lower luminescence efficiency. The biggest challenge today is to find new EL materials to produce multi- and full-color EL display panels. In this paper, high quality AIN thin films doped with TbF3 were prepared by radio frequency magnetron reaction sputtering.High pure Al metal and TbF3 slice were used as target materials and N2, Ar as sputting gases with total pressure 1Pa and 20/80 ratio of N2 to Ar. The influence of preparation conditions on photoluminescence brightness of the AIN: TbF3 thin film was studied and the photoluminescence brightness improved with increasing substrate temperature. The optimal concentration of Tb3+ in AIN: TbF3 thin film is 4.0mol%. Electroluminescence has a similar dependence on the concentration of Tb3+ and substrate temperature. The characteristic luminescence of Tb3+ ion was obtained in AIN: TbF3 thin film electroluminescence device prepared with 600℃ substrate temperature and 4.0mol% concentration of TbF3. The new material is provided for EL and which is the first report to our knowledge.关键词：electroluminescence;thin film;AIN：TbF394|109|1更新时间：2020-08-11
- 摘要：The concentration quenching on active ions in laser crystals has effects on their optical and laser properties, so it is necessary to study. Recently, Yb3+ doped solidstate materials are attractively used as gain media of high efficiency, high power laser with the development of InGaAs laser diode. Among the numerous Yb3+ doped crystals,Yb: YAG has exhibited enormous potential for high efficiency and high power lasers because of its excellent optical and spectroscopic performances, high thermal conductivity and tensile strength. Since Yb3+ possesses only two relevant electronic states-the 2F7/2, ground state and 2F5/2 excited-separated by about 10,000cm-1, the concentration quenching is nonexistent in Yb: YAG in principle. However, the measurements on fluorescence lifetimes of unannealing Yb: YAG with different doping level demonstrated that there were concentration quenching in Yb: YAG crystal for Yb3+doping concen-tration of more than 10at.%. This phenomenon was studied, and the decrease of fluorescence lifetime is attributed to Yb2+, which results in color center and lattice distortion of Yb: YAG. Trace impurity ions such as Er3+ and Tm3+ are detected by means of ICP and X-ray excited emission spectrum, which are also responsible for the concentration quenching at high Yb3+ doping level. The optimal Yb3+ doping level in Yb: YAG crystal is less than 20at.%, which is determined by the fluorescence lifetime measurement.关键词：Yb：YAG crystal;concentration quenching;fluorescence lifetime;dopingConcentration160|286|3更新时间：2020-08-11
- 摘要：The influence of antimony (Sb) doping on the luminescent properties of lead tungstate crystals (PWO) has been investigated. Transmission spectra, UV-excited emission spectra and their excitation spectra of PbWO4: Sb and undoped PWO before and after annealing in air were reported. the emission spectra of PWO and PWO: Sb before annealing were analyzed by fitting with three Gaussian subbands respectively. Sb doping improved the luminescence of PWO by enormously increasing its light yield.While the green emission band is enhanced, the red one is restrained. On the ground that the improvement by Sb doping is similar to the air annealing effect on PWO luminescence, the mechanism of Sb doping and the origin of the green emission is brief lydiscussed.We suggested that the green emission originate from some local excess oxygen defects, such as (WO42-+Oi) centers (here Oi means interstitial oxygen atom) because annealing in air increased the green emission significantly. For the mechanism of Sb doping, we supposed that Sb3+ ions and Sb5+ ions simultaneously exist in PbWO4: Sb crystal. Sb3+ ions on Pb2+ sublattice Sbpb3+ compensate the local surplus negative charges bringing in by lead vacancies Vpb resulting from the higher volatility of raw materials PbO than that of WO3, and so will compete with the creation of oxygen vacancies Vo which have the same charge compensation effect. While the concentration of Vo decrease, the possibility of Oi increase. But after air annealing, the emission intensity of PbWO4: Sb is less than that of PWO. This may be due to Sb5+ on W6+ sublattice Sbw5 which prevent the further increasing of (WO42-+Oi) centers in PWO: Sb by air annealing.关键词：PbWO4 crystals;luminescent properties;lattice defects;Sb doping92|77|2更新时间：2020-08-11
- 摘要：The temperature dependence of interface characteristics in An/GaP contact system has been studied by X-ray diffraction (XRD) and scanning electron microscope (SEM).The measurements show that even at temperature below 400C the interface reaction will form a little amount of An-Ga inter-metallic compound. Its main constituents are (GaAu)H, Ga2Au. In the case of alloying at a higher temperature 550C the surface of GaP compound has decomposed. The interface reaction is enhanced accompanying by rapid atomic inter-diffusion. Extensive out-migration of gallium atoms into gold film overlay and penetration of gold atoms into the GaP layer have been observed. The chemical reaction between An-Ga occurs and form (GaAu)H, Ga2Au and (GaAu)8O etc.These experimental results suggest that the interface between the An layer and GaP is a metal-semiconductor interfacial reaction and alloying re-growth layer, which contains An, Ga and P atoms. The An-Ga inter-metallic compounds can contribute to the improvement of mechanical strength and the adhesion of An film. The SEM observation indicafes that as alloying temperature exceeds the An-Ga eutectic temperature 470C,the surface morphology of M-S contact becomes rougher and more inhomogeneous.With rising the temperapture, the microcrystal grains of interface layer become larger.At 600℃, the micro-crystallization effect is obvious. In fact, the alloying condition is not favorable to the of ohmic contact fabrication.关键词：An contact to GaP;interface reactions;XRD spectral;surface property118|104|0更新时间：2020-08-11
- 摘要：808nm high power semiconductor laser was widely used to pump Nd: YAG laser.Here we report the quasi-continuous wave (QCW) operation of 808urn Al-free InGaAsP/GaAs high-power 1-cm-wide laser array bar. The active layer structure we used here was the separate confine heterostructure (SCH) single quantum well. An output power of 37W with frequeney of 1000Hi, pulse width of 200μs and duty-cycle of 20% was achieved at room temperature when driven by excitation current of 49A, which was the upper limit of our driving source. The slope efficiency of the bar was 1.03W/A.The power efficiency was estimated to be about 39%.关键词：quasi-continuous wave;array;semiconductor laser;duty cycle108|74|1更新时间：2020-08-11
- 摘要：The spontaneous emission properties of a single layer organic film in flat optical microcavity were studied. The optical microcavity was formed by a layer of a Tris(8-quino-linoloato) aluminum (Alq) film sandwiched between a quarter-wavelength distributed Bragg reflector (DBR) and a Al metallic reflector. The DBR used here is a chirped one,the structure of which is G[H1L1]6[H2L2]6[H3L3]4H .There the G label represents the glass substrate, the notation [H1L1]6 implies a quarter-wave of high-index material H,followed by a quarter-wave of low-index material L, and 6 times. The high-index material is TiO2 with a refractive indices of 2.0, the low-index material is SiO2 with a refractive indices of 1.46. The Bragg wavelength of the three stacks is 430nm, 570nm and 630nm, rspectively. The stopband range of the DBR was extended from 420nm to 650nm.The PL spectrum of the microcavity and that of Alq film was compared at the same excitation condition. It showed that the PL spectrum of Alq film is a wider band, centered at 521nm with a FWHM of 93nm. The PL of the microcavity exhibits amultimode emission that locates at blue, green and red spectral region. It showed that there are 4 peaks in the PL spectrum of the microcavity. The three strong peaks are located at 497nm, 555nm and 615nm, respectively. The other weaker peak is located at 449nm. A strong spectral narrow from 100nm (full width half maximum)of film to 5.6nm of microcavity in PL is observed. The results implied that using microcavity structure is a useful way to achieve multi-color emission.关键词：organic microcavity;spectral narrow;optical microcavity101|78|2更新时间：2020-08-11
- 摘要：By strictly controling the cooling and heating rate for reactor and using generous hot deionized water to rinse the deposition, the high purity organic semiconductor material 3, 4, 9, 10 perylenetetracarboxylic dianhydride (PTCDA) was preparde with raw material 1.8-naphthalic anhydride. Sublimated in vacuum, the purity of PTCDA was higher than 99% by analyzing purity with Varian high efficiency liquid phase colormetric spectrum. The measurement and analysis of HP5988A type mass spectrum of the sample is located at 392, which is consistent with the molecular weight of PTCDA. The measurement and analysis of the infrared absorption spectrum of the sample show it has anhydried and benzene base. The hydrogen atom's ascription was analyzed by nuclear magnetic resonance spectrum. X-ray diffraction spectrum shows PTCDA is monoclinic and its thin film deposition is preferred orientation. The analysis of the visible absorption spectrum shows that the absortion edge exists between 560~410nm which is located at the blue and green range. At the same time obvious exciton atsorption peak exists and the exciton band gap is 0.8eV, For 540nm wave, the relative absorption Intensity can be about 78%. For 500nm wave, the relative absorption intensity decreases to 50%. With the decrease of the incident wavelength, the relative intensity decreases linearly. For visible wave length larger than 570nm, it is transparent.147|122|3更新时间：2020-08-11
- 摘要：In this work, we first investigated the chemiluminescent properties of ethidiumbromide, and find that RNA can enhance the chemiluminescent intensity of reaction between ethidium bromide and KMnO4 in a strong acid medium. There is a linear relationship between the chemiluminescent intensity obtained in the system of EB-KMnO4-RNA and RNA concentration, therefore, a new chemiluminescent analytical method for thedetermination of RNA is established and used to determine RNA in synthetic samples.The linear calibration ranges is 0.10~10.0μg/mL and the detection limit is 0.06μg/mL for RNA, the relative standard deviation is 3.8% for 3.5μg/mL RNA. Interference ionswere examined. The precision, accuracy and selectivity of the method are satisfactory.关键词：chemiluminescence;ethidium bromide;RNA90|75|0更新时间：2020-08-11
- 摘要：The frequency spectrum analysis of RF signals has been become a key technology in modern electronic countermeases. Acousto-optics frequency spectrum analyzer is very prospective for its performance. To detect all information carried by the RF signals including amplitude, frequency and phase, and to increase significantly the dynamicr ange, the scheme of AO(Acousto-optics) heterodyne frequency spectrum detection has to be used. In this paper, the principle and realization of a sort of AO heterodyne detection receiver are reported, and especially the method of calculating sensitivity has been discussed in detail which has been proved highly effective by our prototype receiver.The feature of the AO prototype receiver are as follows:The dynamic range ≥50d Bfrequency resolution 2Hz bandwidth 20MHz central frequency 140 MHz.关键词：acousto-optics;heterodyne;spectrum analysis;sensitivity84|64|0更新时间：2020-08-11
- 摘要：For solving "bottlenects effects" in a computer and improving its calculation rates,optical interconnections within a computer are now well investigated in the world. And as one of the basis of optical digital computer, all-optical interconnections are also extensively studied in recent years. All-optical interconnections within digital optical computing systems requir that light beam carrying information be deflected to another position reqired from one position to realize real-time, optical addressing. In this paper we proposed a new method for solving such a problem, namely stratified grating composed of nonlinear media characterized by light intensity-dependent refractive indices was used as a basic optical interconnection device, so Bragg reflecting condition of incident signal light in the grating is changed by means of refractive index change of the nonlinear media caused by the change of external controlling light intensity, then the signal beam is deflected to a position reqired. The optical limiting effect realized in ZnS/ZnSe stratified grating is reported in this paper for the first time, and the nonlinear threshold is about 140mW, the limiting threshold is 24mW. It shows that the dominant mechanisms of the optical limiting in the experiment is the large photogenerated free-carrier defocusing contribution to the linear refractive index of the material from the two-photon absorption (2PA). The optical limiter fabricated by multiple layers structure of semiconductor materials has not only lower threshold and wider frequency response, but also the characteristics of which the threshold of the limiter is dependent on all kinds of parameters of the device. So its adaptability is superior to single layer structure limiter's.103|97|0更新时间：2020-08-11
- 摘要：In this paper, we studied the micro mechanism of Anti-Stokes fluorescent cooling at molecular scale. The conception of "Single Molecule-Photon Cryocooler (SMPC)" was suggested for the first time. The viewpoint of cooling with one single molecular was clarified. One single molecule can be the smallest cryocoolcr when some special conditions are satisfied. We Investigated its running processes and charactors through analyzing the working principle of SMPC. At last, the key conditions that influencing on the SMPC's cooling efficiency of SMPC were discussed.关键词：photon engine;laser cooling;anti-Stokes fluorescence93|88|3更新时间：2020-08-11
- 摘要：In the present paper, a novel luminescence enamel glaze and its processing have been investigated. The luminescence material used was that based on SrO·nAl2O3 doped with Eu2+, and Dy3+ ions. The influences of compositions of the basic glaze on the luminescent effect were also discussed. The compositions, Al2O3, B2O3 and SrO favor the luminescence and its afterglow of the luminous glazes. The analyses of XRD and SEM indicated that the crystals of luminescent materials are still present in the enamel glaze layer after sintering. The luminescent crystals contributed to the luminescence of the enamel glaze.With this new kind of luminous enamel glaze, some enamel products, such as enamel signboard, enamel ware, can be prepared,and their technical characteristics can meet the requisitions of Chinese Standard GB/T 1855-93, the luminescence afterglow will be over 12 hours.98|89|1更新时间：2020-08-11
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