最新刊期
卷 20 ， 期 2 ， 1999
- 摘要：We synthesized nancocrystalline Y2-xSi2O7:Eux by Sol Gel process. And normal bulk powder was achieved by annealling the nanocrystal. Emission spectra of Y2-xSi2O7:Eux with x ranging from 0.01 to 1 were measured to show the quenching concentration. As a result, nanocrystal gets a stronger luminescence intensity than the corresponding bulk powder’s. Furthermore, nanocrystal has a higher quenching concentration. The result suggests a new way to the study of luminescence nanocrystal.关键词：concentration quenching;nanocrystal;Y2-xSi2O7：Eux102|82|2更新时间：2020-08-11
- 摘要：The chemical preparation method and spectrum characteristics of YPO4:Pr3+ nanocrystal powder are reported for the first time. The structure analysis shows that the sample is nano material with radius of about 20nm. A strong emission from 3P1 level of Pr3+ ion is observed under excitation at 3P0 level by a Ar+ laser set at 488nm. This is caused by the efficient cross relaxation energy transfer of {1D2×3H6→3P1×3H4} between different Pr3+ ions.关键词：YPO4：Pr3+;nanocrystal;spectrum95|102|2更新时间：2020-08-11
- 摘要：The transient behavious of ZnS:Mn2+ nanocrystallites dispersed in Pyrex glasses were studied by emission, excitation, time resolved spectra and luminescence decays. It was found that blue emissions peaked at 389 and 404nm are not self activated luminescence due to D A pairs but the emission from Mn2+ located at the intersticial sites. This is in good agreement with the results of the previous EPR experiments. There are no energy transfers between this emission and Mn2+ ions. The lifetimes of 4T1→6A1 transition to Mn2+ions were shortened compared with that of ZnS:Mn2+bulk powder. It is suggested that the ratio of the energy transfer from ZnS to Mn2+ ions gets faster by quantum confinements and efficient radiationless channels provided by surface states.关键词：nanocoposites;luminescence lifetime;time correlated single photon counting technology78|81|3更新时间：2020-08-11
- 摘要：Two sites of Mn2+, (Mn2+)sub and (Mn2+)int were found by photoluminescence and excitation spectra in ZnS:Mn2+ nanoparticles and Pyrex glasses composite. Electron paramagnetic resonance(EPR) experiments confirmed further that there are (Mn2+)sub, (Mn2+)int and Mn clusters formed by strong dipole-dipole interactions. The possibilities to form Mn clusters are larger than to form the other two sites. The increases in g1 factors and superfine structure constants |A| with decreasing the diameters of the nanocrystals were observed also. The g shift due to the hybridization between s p states of ZnS and d states of the Mn ions by carrier quantum confinement ( R<aB) effects were discussed and analyzed by Cardona model using k·p perturbation.关键词：nanoparticles and Pyrex glasses composites;EPR spectra;g factor and superfine structure constant107|119|4更新时间：2020-08-11
- 摘要：In this paper, photorefractive effect of polymer doped inorganic nanoparticles is reported. In the polymer PR material, Cu2S/CdS/ZnS nanoparticles were used as photosensitizer, PVK was used as carrier transport agent, and EPNAC moleculs were used as electroptic molecules. Two-wave-mixing was studied. The experimental results prove that this kind of nanoparticle can be used as photosensitizer in polymer PR materials.关键词：nanoparticle;photosensitizer;photorefractive effect;two-wave-mixing91|121|2更新时间：2020-08-11
- 摘要：The processes of fabrication and poling for DANS (4-dimethylamino-4’nitro stlibene) side-chain polymer film waveguide have been described in this paper. By using the prism coupling technique in yntegrated optics, the optical properties of the wave-guide have been characterized before and after poling and UV photobleaching respectively. It has been demonstrated by the experiment results that the extraordinary refractive index of the wave guide was increased obviously and the ordinary refractive index of the waveguide was reduced after poling, and the refractive indices of the waveguide were reduced about 0.02 after UV photobleaching.关键词：poled polymer;waveguide;optical property110|265|1更新时间：2020-08-11
- 摘要：In this paper, we studied the anti-Stokes fluorescent cooling efficiency of laser dye with molecular vibrational energy levels in theory. We calculated the ability of Rhodamine 101 in anti-Stokes fluorescent cooling by its absorption spectrum and fluorescent spectrum. The cooling condition and relative efficiency of the material was given.关键词：laser cooling;anti-Stokes fluorescence;laser dye103|109|0更新时间：2020-08-11
- 摘要：In this paper, we discussed two mechanisms, Anti-Stokes Fluorescent Cooling in Single Center(ASFCSC) and Anti-Stokes Fluorescent Cooling by Energy Transfer (ASFCET). We also discussed the relationship between ASFCSC and ASFCET and derived their working condition. It was pointed out that the two mechanisms might run simultaneously to increase the cooling efficiency.关键词：anti-Stokes fluorescence;laser cooling;energy transfer122|145|3更新时间：2020-08-11
- 摘要：In this paper, fabrications of GeO2-PbF2-WO3-Tm2O3 glasses were studied. The Raman spectra of different samples have been measured. In this system an efficient pumped wavelength for upconversion emission was confirmed, and their upconversion emissions by 650nm pumped by 650nm were observed at room temperature.关键词：upconversion88|156|0更新时间：2020-08-11
- 摘要：We have investigated the decay of nonequilibrium phonons in YAG:Pr3+ (1.0at.%) and LiYF 4:Pr3+ (1.0at.%) at a temperature of 9K. Nonequilibrium phonon populations at 43.0, 51.9, 66.0 and 113cm-1 are generated monochromatically with a high power pulsed far-infrared laser using defect-induced one-phonon absorption, and their temporal and spectra evolution determined using a time-resolved vibronic sideband spectrometer. We find that two decay mechanisms dominate the nonequilibrium phonon relaxation in the crystals: anharmonic decay via three-phonon-interactions and two-phonon-one-electron inelastic scattering processes. In LiYF4 system, we observe the broad band distribution that results from the anharmonic decay of the initial monochromatic phonon population. In YAG system, the latter mechanism leads to the evolution of a highly peaked phonon distribution that persists for several phonon generations.关键词：nonequilibrium phonons;high-frequency phonons;lattice dynamics;YAG;YLF103|122|0更新时间：2020-08-11
- 摘要：Under the effective-mass approximation, the paper studys the effect of dielectric confinement on an exciton in spherical and cubic QD(quantum dot). The present result shows that effects of QD shape on excitonic states is not neglectful.关键词：dielectric confinement;quantum dot;exciton94|163|0更新时间：2020-08-11
- 摘要：Mg-doped GaN with cubic structure have been grown by molecular beam epitaxy on sapphire substrate. Temperature-dependent photoluminescence of heavily Mg-doped GaN have been investigated in order to study the properities of donor-acceptor pair recombination. We have found unusual temperature dependent behaviors of donor-acceptor pair recombination in heavily Mg-doped GaN. The photoluminescence intensity of donor-acceptor pair recombination decreases below 35K and then increases as the temperature increases up to 100K. This behavior may be explained by employing three energy level system, e.g. shallow donor level, shallow acceptor level and hole trap level. The main transition processes and their dynamic processes of non equilibrum holes, which bumped by excited laser, have been studied. The holes are caught in the hole traps and they subsequently transfer from the traps to shallow acceptors by tunneling, where recombination with electrons takes place. The theoretical calculations are in accordance with the experiment results. The PL intensity of donor-acceptor recombination in heavily Mg-doped GaN is determined by the effects of hole trap and tunneling.关键词：GaN;photoluminescence;tunneling effect112|116|1更新时间：2020-08-11
- 摘要：The operating characteristics of Al-free InGaP/InGaAsP/GaAs separate confinement heterostructure single quantum well (SCH. SQW)high pover laser grovn by LP MOCVD are reported. The internal differential quantum efficiency ηi is closed 100%. The external differntial quantum efficienty ηd of 75% and characteristics temperature to of 146℃ are achieved, CW total output power both facets of 2.6W single quantum well laser with 100μm width, 1.1mm cavity length is obtand threshold current desity Jth . Reciprocal differential quantum efficiency 1/ηd. Emisson wavelength and charactreistic temperature to as function of laser cavity length L respectively have been measued and researched. Dependence of Jth and ηd respectively on temperature T have been goven and explained.On the basis of these work, we researched and fabricated 808nm InGaAsP/InGaP/GaAs separate confinement heterostructure single quantum well (SCH SQW) laser array with 30 elements, 1cm long laser bar. Slope efficiency 1.2W/A. Laser array working wavelength at 808nm, QCW output power is up to 27 watts.关键词：semiconductor lasers;quantum well;laser arry107|138|0更新时间：2020-08-11
- 摘要：Aging propertys on compound of anthrone were studied with artificial (at 555nm homogeneous light, 2h) and natural aging (exposed to the light of day by 26 months). The results show that fluorescence intensity of the natural aging and transmissivity of the resin were decreased 48% and 40% respectively, and reason of light aging is main the resin aging.101|131|2更新时间：2020-08-11
- 摘要：It was found that catechol, p-t-butylpyrocatechol, hydroquinone and protocatechuic acid inhibited chemiluminescence from luminol-H2O2-Co2+ reaction. On this basis, a flow injection procedure combined with inhibited chemiluminescence detection was developed for the determination of these compounds. The method is fast, simple and sensitive. These polyphenols were detectable at picomolar levels. Furthermore, the mechanism of chemiluminescence inhibition by polyphenols was proposed to be due to the reaction between polyphenol and radical intermediates of chemiluminescent reaction.108|152|6更新时间：2020-08-11
- 摘要：Aluminum nitride thin film was successfully prepared by radio frequency magnetron sputtering with target of high pure Al in atomosphere of high pure N2, Ar mixture (purity is 99.999%). Effect of different gas ratio and substrate temperature on crystallinity of the thin films was studied. Annealing can improve the crystallinity. Blue-violet cathodoluminescence was found at room temperature in the AlN thin film annealed at 960℃ for 1hr.关键词：thin film;AlN;cathodoluminescence115|148|2更新时间：2020-08-11
- 摘要：The luminescent and long phosphorescent properties of MAl2O4:Eu2+、RE3+ (M=Mg, Ca, Sr, Ba;RE=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) with distorted stuffed tridymite were researched. The luminescence attributed to the 4f 5d transition of Eu2+. The incorporation ofRE3+ ion into the MAl2O4:Eu2+system was as the auxiliary activator which provided the proper trapping levels. We could not see the luminescence ofRE3+ though excited with the characteristic excitation wavelength of RE3+. We analysed the luminescent and long phosphorescent properties of this type of host codoped with rare earths, and made the conclusion that Pr, Nd, Dy, Ho, Er could effectively prolong the life time of MAl2O4:Eu2+system. The long phosphorescent rule is Sr>Ca>>Ba.关键词：rare earth;phosphorescence;thermoluminescence;long phosphorescence;traps258|215|61更新时间：2020-08-11
- 摘要：Eu3+ doped SiO2 aerogel film were prepared by sol-gel process. The surface structure was observed by AFM. Excitation,emission and time resolved spectra were measured. The time resolved spectra show that the emission from 5D1 was decay, while the ones from 5D0 show a increasing process in decay process. Luminescent dynamic equations were setup to explain these decay process.关键词：SiO2 aerogel thin film;time resolved spectra;dynamic equations116|161|1更新时间：2020-08-11
- 摘要：An organic laser based on the soluble conducting polymer, Poly[1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-3,5-dimethoxy-1,4-phenylene] (CNMBC-Ph) has been fabricated. The laser was pumped by the light pulses from a third harmonic radiation of a Nd ⅩⅣ YAG laser. The stimulated emission was achieved in the blue wavelength region with the peak at 450nm. The threshold power density is about 2.8MW/cm2.The maximum peak power of the laser output achieves at about 40kW.关键词：polymer;stimulated emission;laser material110|153|0更新时间：2020-08-11
- 摘要：GaInSb/GaSb quantum wells have been grown by MOCVD technique and the photoluminescence (PL) measurement was performed at 4K. The effects of GaSb capping layer thickness, GaInSb well width and indium content in well on the PL spectra were investigated in detail. It was found that the carrier concentration increased with decreasing the thickness of the capping layer. The FWHM of photoluminescence spectra broaden as the In content in well increased because more clusters should exist in the alloys with high In content and consequently result in the degeneration of the optical quality.关键词：GaInSb;quantum well;photoluminescence;MOCVD105|142|0更新时间：2020-08-11
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