共查询到20条相似文献,搜索用时 812 毫秒
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采用减小焦线宽度,以使低能泵浦功率密度达到适当值的方法,在“星光”装置上开展了碰撞激发机制X射线激光实验。在泵浦能量约130~180J,焦线宽约80μm,靶面功率密度约10TW/cm ̄2条件下,观察到了类Ne锗23.2nm,23.6nm,28.6nm三条激光线。对有可能实现单色X射线激光的元素Zn,仅观察到类Ne锌26.2nm,26.7nm两条激光线。 相似文献
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测定了光谱纯稀土化合物Y2O3,La2O3,Lu2O3中微量杂质在488.0nm和514.5nm激光线激发下的光致发光谱以及在可见光445~741nm范围内吸收谱,Y2O3,Lu2O3样品在448.0nm和514.5nm激光激发下都有发光效应,而La2O3样品只在488.0nm激光激发下才发光,分析了结果表明,Y2O3,La2O3,Lu2O3的发光谱分别是由其存在的微量Er^3+,Sm^3+和Eu 相似文献
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光纤预共振喇曼光谱的实验研究 总被引:1,自引:0,他引:1
应用液芯光纤技术,提高了预共振喇曼光谱强度10^2倍以上,用10mW较长波长(514.5nm,488.nm,454.5nm)激光激发,观察到了α甲基吡啶的预共振喇曼光谱线。 相似文献
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低泵浦能量类氖锗等离子体软X射线激光实验 总被引:2,自引:1,他引:1
提出并采用具有一定时间间隔的双束脉冲加热锗薄膜靶方法,在泵浦激光能量100J,靶长10mm的实验条件下,观察到波长19.61nm和23.63nm两条类氖锗3s-3p激光跃迁线。19.61nm(J=0-1)的激光跃迁线发射强度较23.63nm(J=2-1)激光线的强度大,其发散角较后者小。 相似文献
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本文给出了软X射线超光滑表面散射的一级近似的一般理论推导,从中给出软X射线的散射传输特性。通过实验测量了λ=24.3nm、25.6nm时具有超光滑表面的Mo、Si样品的反射率和λ=4.46nm时熔石英超光滑样品的反射单。对4.46nm进行了了散射测量,可以明显观察到软X射线的非正常反射现象。 相似文献
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单模光纤窄带波分复用器的研究 总被引:1,自引:0,他引:1
由组合波导理论出发,分析了超长耦合器合区光纤间的功率耦合特性以及器件的偏振特性,并提出了研制二段窄波分单模光纤波发复用器的新方法,在研制常规耦合器的工艺基础上,先后研制成功1310nm或1550nm单窗口窄带波分复用器及1310nm或1550nm双窗口等三种复用间隔约14nm的窄带波分复用器,其波长隔离度大于20dB,具有2~3nm的带宽,偏振灵敏度小于0.1dB,附加损耗小于0.5dB,这些参数 相似文献
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Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide 总被引:1,自引:0,他引:1
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs. 相似文献
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A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users. 相似文献
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S. G. Nedel’ko M. A. Krysyuk A. L. Apanasenko L. N. Lymarenko Z. T. Moroz 《Journal of Applied Spectroscopy》1997,64(1):55-61
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped
with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly
described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation
(5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum
cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics
of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure
crystals is analyzed (preliminarily).
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997. 相似文献
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A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
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Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use. 相似文献
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References: 《声学学报:英文版》2008,27(1):23-33
The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results. 相似文献
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With a novel light-weight and absolutely calibrated ultraviolet (UV) spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands (320 - 335 nm) using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model (Tracy). The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon. 相似文献
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For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters. 相似文献
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Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers. 相似文献