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据我们所知,这是第一次报导用连续波A^+r激光器(333-364nm)在近紫外光在10mol%掺GeO2光纤中侧写入折射率光栅,在紫外光功率密度在1.7×10^5w%/cm^2时感生的折射率数值达到高达1.9×10^-4。观察到的光栅表现出的温度稳定性与用Kr激元激光器(243nm)写入的光栅相同。 相似文献
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利用1.313μm激光泵浦掺铒石英光纤产生上转换放大自发辐射 总被引:1,自引:0,他引:1
报道了利用1.313μm波长调Q锁模Nd3+:YLF激光泵浦国产掺铒石英光纤同时产生可见光463nm(463nm,475nm,485nm,494nm,501nm,510nm),525nm,540nm(525~564nm),二次谐波信号656nm(656~675nm)和近红外804nm(784~820nm)等波段放大自发辐射的实验结果.在可见光463nm波段,在高泵浦功率下观察到随泵浦光功率增大,邻近几个中心波长与463nm波长信号产生类似级联共振放大增强的现象。同时发现几个中心波长辐射光谱宽度随泵浦光功率增加有加宽的关系,这与现有实验结果报道不一致。实验中还发现3m长光纤与4.5m长光纤在输出可见光自发辐射光谱方面有很大的不同.3m光纤在相等泵浦光功率下.出现邻近波长共振放大加强的几率比4.5m光纤小得多。根据能级跃迁关系提出了共振四光子吸收将基态4I15/2离子抽运到高能态2G7/2,然后跃迁辐射回到4I13/2态的机制,给出了实验结果的初步机理解释。 相似文献
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合成了吸收波长为1455nm的红外域调Q、锁模染料.它的碘乙烷、1,2-二氯乙烷及二甲基亚砜溶液对1340nm激光进行锁模时.显示优良性能.锁模脉宽为90~100ps。它的聚砜薄膜能对1064nm激光进行满意调Q,脉宽为10ns. 相似文献
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采用超声氯分子束和时间分辨质谱研究了由1064nm近红外激光诱导InP(100)表面蚀刻反应的产物质量分,入射Cl_2分子束的平动能效应,激光能量密度和表面温度的影响,并讨论了反应机理。 相似文献
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理论上简要地分析了在可见光波段碘荧光强度与激发激光波长的关系 ,并用波长为 5 32nm半导体倍频Nd :YAG激光、波长为 5 14 .5nm、5 0 1.7nm、4 96 .5nm和 4 88nm的氩离子激光激发碘分子 ,通过对获得的荧光信号分析得出 ,五种波长的激光均可诱导出碘荧光。对相同的激光功率 ,波长为 5 32nm的倍频Nd :YAG诱导出的碘荧光信号比波长为 5 14 .5nm的氩离子激光强 ,两种激光均可作为碘气体的激发激光。其它三种波长激光诱导出碘荧光强度弱 ,在激发激光传输方向衰减明显 ,不适合作为碘荧光的激发激光。 相似文献
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为了有效降低偶氮苯聚合物薄膜全光开关信号的本底,提高全光开关信号的调制深度,利用线偏振光合成圆偏振光的原理,设计了一种新的线-圆双偏振态光束抽运光路。实验用532 nm光作为抽运光,632.8 nm的He-Ne激光作为探测光。532 nm的光先分为功率相等但偏振正交、相位差为π/2奇数倍的两束线偏振光,然后再合成一束抽运光。通过调制其中的一束来实现线偏振与圆偏振抽运光之间的转换,从而实现样品光致双折射的产生与擦除。以掺杂分散红1(DR1)的聚甲基丙烯酸甲酯薄膜(PMMA)为样品进行实验。结果表明,用此光路,样品全光开关信号的调制深度达到92%,远远高于传统的单一线偏振光束抽运光路的实验结果。 相似文献
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基于激光边带注入法在铷原子蒸气中实现了电磁诱导透明、光脉冲的减速和存储.为实现对铷原子的相干操控,将主激光器的输出锁定在铷87原子D1线F=1→F'=2的跃迁谱线上,经6.8 GHz电光调制器(EOM)调制后,负一阶频率边带与D1线F=2→F'=2跃迁频率共振.将负一阶频率边带注入锁定从激光器,主激光器和从激光器输出的两束激光和铷原子的两基态超精细能级达到双光子共振,实现相干操控铷原子.将主激光器和从激光器输出的两束激光作为探测光和耦合光输入到铷泡中,通过操控两光束的波形和开关观察到电磁诱导透明、光脉冲的减速和存储. 相似文献
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二氧化硫是大气中最常见、最重要的污染物之一.差分吸收激光雷达探测二氧化硫具有高时空分辨率、高探测精度等优点.用两台Nd:YAG 激光器泵浦两台染料激光器后,通过倍频晶体得到测量大气二氧化硫所需的两个波长,它们分别是on=300.05nm 和off=301.5nm.将两束光束用几组反射镜合为一束光束,经扩束镜6 倍扩束后垂直发射进入到大气中.接收望远镜收集两个激光波长的大气后向散射信号,信号采集单元记录两个波长的后向散射回波信号的垂直高度分布.通过数据反演获得二氧化硫的高度分布.初步实验结果表明,实验期间合肥西郊董铺岛垂直高度0.3~1.6km 的二氧化硫在0~14ppb 范围内波动.最后分析并估算了该二氧化硫差分吸收激光雷达的四个主要误差来源. 相似文献
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Fluorescence spectra of perylene-doped polymer fiber were measured in both radial and axial directions, i.e., for leaky and guided beams, by exciting the fiber with a pulsed laser of 460-540-nm wavelength. Green (540-550 nm) and yellow (580 nm) peaks were observed in the radial fluorescence spectrum. Measuring fluorescence change at positions closer to the input end and progressing forward to the output end, we observed that green fluorescence decreased rapidly corresponding to an attenuation constant at incident laser wavelength. In contrast, yellow fluorescence decreased gradually, because it was induced by the absorption of green fluorescence, which attenuated more gradually than incident laser. Therefore, in axial output beams, green fluorescence was much weaker than yellow. As incident laser power increased, intensities of axial green fluorescence and radial fluorescence (both green and yellow) saturated to a certain level. In contrast, axial yellow fluorescence increased nonlinearly with increase in laser power. The output light intensity became strongest at a fiber length of 20-30 mm. These phenomena were analyzed theoretically taking self-absorption and stimulated emission by fluorescent dyes into consideration 相似文献
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Bound-bound electronic transitions in simple molecules are generally suited to realize efficient multiline laser oscillation in the visible and ultraviolet spectral region. By means of optical excitation with argon and krypton lasers, CW laser oscillation could be obtained for various homonuclear diatomic (dimer) molecules such as Li2 , Na2 , K2 , Bi2 , S2 , Te2 , and I2 , with emission of several hundred laser lines in the spectral range of about 400-1350 nm. The principles of these lasers and the general dependence of threshold and output power on temperature, pressure, length of vapor zone, and some other parameters is discussed. To achieve satisfactory CW operation, low quenching losses for the upper laser level population and a sufficiently fast relaxation of the population of the lower laser level are necessary. Under optimum operation conditions, efficiencies up to 15 percent, multiline output powers up to 400 mW, and single line-single frequency output powers up to 200 mW were achieved. These dimer lasers are three-level laser systems. In case of coherent optical excitation, two-photon or Raman-type processes contribute to the amplification process. Due to these mechanisms the forward direction is strongly favored and in a ring laser system spontaneous unidirectional oscillation is obtained. By means of a suitable three-level model, analytical and numerical calculations of gain profiles are performed and compared with experiments. These optically pumped molecular lasers are suited for various spectroscopic and kinetic investigations, for frequency standards or as simple and efficient systems to convert pump laser radiation into other spectral regions. 相似文献
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We present a new laser probe, a differential polarimetric interferometer, which is dedicated to the study of common failure mechanisms in microelectronic interconnects. Our investigation is mainly concentrated on the study of thermomechanical stress build-up and electromigration in metal lines. In the differential interferometer, two laser beams, separated by a few microns, are reflected from the surface of the device under test. Reflectance, phase and polarization changes between the two beams can be observed, this allows surface temperature and surface bending measurements together with the observation of stress induced in the silicon dioxide layer by Joule thermal expansion. The laser probe provides unique and useful information about local thermal effects due to electromigration. It also shows, for the first time to our knowledge, induced local stress effects due to the mismatch of thermal expansion coefficients of the metal, Si and SiO2 involved in running interconnect lines. 相似文献
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For pt. I see ibid., vol., 31, no. 8, p. 1525-32 (1995). The plasma temperatures in microwave discharged CO2-N2-He laser gas mixtures were examined using the spectroscopic and electrostatic probe methods. A vibration temperature of N2 molecules, obtained spectroscopically, was determined to be nearly 7000 K without gas circulation and to be nearly 4000 K at the mass flow rate of 4.2 kg/h. It is found that an efficiency of laser output power exceed 14% (RF to laser output power conversion ratio) below the vibration temperature of 4000 K. The values of vibration temperature obtained were higher than those reported in DC discharges 相似文献
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Cavity ring-down spectroscopy and degenerate four-wave mixing have been applied for spectroscopic studies, temperature determination, and measurement of relative dipole transition moments of photochemically produced sodium hydride. In our experiment, NaH was formed within a heat-pipe oven after 3p excitation of sodium in a hydrogen atmosphere with a second dye laser. The reaction product NaH was probed in the near ultraviolet part of the spectrum at 382 nm with 1-4-μs delay to the excitation pulse using both a linear and nonlinear spectroscopic technique with a pulsed dye laser source (pulsewidth 15-ns full-width half-maximum). The strengths and limitations of these two spectroscopic techniques are discussed. Since the two processes depend on different parameters and the image-forming beams have different properties, it is difficult to define a single criterion for comparison. But our measurements indicate that cavity ring-down spectroscopy is a powerful tool with a sensitivity better than 109 particles per cm3 and quantum state which is comparable to degenerate four-wave mixing in our case 相似文献
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从理论和实验上研究了从激光器直接输出高阶拉盖尔-高斯(LG)光束和高阶厄密-高斯(HG)光束。首先从理论上研究了高阶LG光束和高阶HG光束的光强分布特性,并进行数值仿真。在实验研究中,利用445 nm的蓝光半导体激光器端面泵浦Pr:YLF晶体,在一定的条件下,能从平凹腔直接输出640 nm波长高阶LG光束和高阶HG光束。实验结果表明:从激光腔内输出的高阶LG光束和高阶HG光束与理论仿真基本一致。文中所报道的获得高阶模的实验装置简单,对产生高阶光束及其应用具有较重要价值。 相似文献