共查询到18条相似文献,搜索用时 15 毫秒
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非线性激光光谱技术在气相介质的痕迹量检测方面有广泛应用。实验采用了具有自稳分光系统的前向简并四波混频(DFWM)布局,在大气压附近不同压强和不同温度条件下研究了碘气体的DFWM 光谱。在饱和泵浦和探测光强的情况下,发现温度与压强的变化对碘在波长555~556 nm 及558~559 nmDFWM 光谱结构影响较大,其中波长为555.1 nm 的跃迁对温度相当敏感。同时仍有少数碘的DFWM 光谱线较强是因为跃迁(558.81 nm)对温度不敏感,可以利用该谱线来探测不同温度下气相介质的浓度变化。所以不同温度与压强对碘气体DFWM 光谱影响的研究在气相介质痕迹量的检测以及燃烧诊断等方面有重要的应用价值。 相似文献
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基于电磁感应透明的弱光非线性研究进展 总被引:1,自引:0,他引:1
利用电磁感应透明实现弱光场条件下的强非线性效应,开辟了一个崭新的非线性光学研究领域-“弱光非线性光学”。主要介绍了基于电磁感应透明的Kerr非线性和四波混频效应。Kerr非线性在全光学开关、全光学逻辑运算和光量子逻辑门等方面有着潜在的应用价值。四波混频也具有非常广泛的应用,其中最重要的是把可调谐相干光源的频率范围扩展到红外和紫外。在简并情况下,四波混频对于自适应光学中的波前再现是很有用的。另外,在材料研究中共振四波混频技术是强有力的光谱分析工具。 相似文献
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提出将简并四波混频激光光谱分析技术用于物质超精细结构检测,加之量子光学理论计算的新方法测量同位素含量。即由实验现象确定出自激振荡频率后,在三阶极化率的基础上,通过量子光学梯形三能级系统的计算,得到了简并四波混频双光子共振吸收下,三阶极化率与原子数密度的关系。 相似文献
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由钠蒸气近4D能级双光子共振光谱证实,存在330nm纯参量四波混频信号,共振时参量四波混频抑制了放大的自发辐射,而激光波长失谐时产生的受激超拉曼散射削弱了参量四波混频。 相似文献
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A theoretical model of liquid plug dynamics powered by vapor explosion in a capillary duct has been proposed in order to provide guidance for designing a fluid propulsion device. The model can evaluate performance parameters such as the amount of useful work, efficiency of energy conversion, generated vapor volume and displacement volume rate of liquid. For example, the efficiency of energy conversion for water under atmospheric pressure and room temperature is calculated at 2.8%. The prediction of the vapor volume agrees well with existing experimental result. The prediction of the displacement volume rate also agrees well with the experimental result and suggests the existence of optimum heat flux at which the displacement volume rate is maximum. 相似文献
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Iodine doped single crystal samples of Hg0.8Cd0.2Te were annealed at temperatures varying from 450 to 600°C in Hg vapor and quenched to room temperature. Hall effect measurements
at 77 K on the crystals cooled to room temperature indicate the samples to be n-type after anneals at high Hg pressures whereas
they turn p-type after anneals at low Hg pressures; the electron concentration increases with increase in Hg pressure. The
results are explained on the basis that the crystals are saturated with (Hg,Cd)I2, with the iodine being present as donors occupying tellurium lattice sites (ITe) and a fraction being present as (ITeVHg)’ species formed from the iodine on tellurium lattice sites (ITe) pairing with the doubly ionized native acceptor defects (VHg/11). The solubility of the ITe species increases with increase in Hg pressure, whereas that of the (ITeVHg)’ species increases with decrease in Hg
This work was supported by NASA under contract NAS8-33245 pressure. Equilibrium constants for the incorporation of the iodine
species as well as the pairing reaction have been established 相似文献
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Honda K. Hirata S. Ohata T. Horii S. Kojima C. 《Quantum Electronics, IEEE Journal of》1987,23(6):839-842
AlGaAs/GaAs rib-waveguide separate-confinement-heterostructure (SCH) distributed-feedback (DFB) lasers emitting at 880 nm were fabricated by a two-step atmospheric pressure metalorganic chemical vapor deposition (MOCVD) growth technique. A CW threshold current as low as 18 mA and an output power of more than 10 mW per facet at room temperature were obtained. Also, single longitudinal and fundamental transverse modes were maintained up to more than twice the threshold current level. 相似文献
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T. L. Chu Shirley S. Chu J. Britt C. Ferekides C. Q. Wu 《Journal of Electronic Materials》1991,20(6):483-488
Polycrystalline films of zinc telluride (ZnTe) have been deposited on glass and conducting semiconductor coated glass substrates
at 270°-350° C by photoenhanced metalorganic chemical vapor deposition (PECVD) using the reaction of dimethylzinc (DMZn) or
diethylzinc (DEZn) and diisopropyltellurium (DIPTe) in hydrogen under atmospheric pressure. The deposited films are always
ofp-type conductivity. Their properties are affected by the DMZn/DIPTe or DEZn/DIPTe molar ratio in the reaction mixture. The
optimum DMZn/DIPTe ratio has been found to be approximately 0.9 on the basis of the open-circuit voltage of ZnTe/CdS heterojunctions
and photoconductivity measurements. Without intentional doping, the deposited films are of high resistivity (>107 ohm-cm) at room temperature, and the resistivity of these films has been controlled by using arsine as a dopant. The structural,
optical, and electrical properties of ZnTe films have been characterized.
Supported by the Solar Energy Institute under Subcontract XL-8-18091-1. 相似文献
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The tunnel current of aluminium/aluminium-oxide/palladium (Al/Al2O3/Pd) junctions, obtained by means of sapphire sputtering, has been measured in air and in hydrogen-nitrogen atmosphere at various H2 concentrations ranging from 2 to 100% and at room temperature. It has been found that the tunnel current undergoes a significant change as a consequence of Pd work function lowering induced by the hydrogen. The ratio between the tunnel current in H2 and in air has a value in the range 102?106, depending on the oxide thickness. The increase of the current occurs in some hundreds of milliseconds if the hydrogen is emitted at atmospheric pressure. 相似文献