共查询到20条相似文献,搜索用时 62 毫秒
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在周期为14.5μm的周期性极化铌酸锂中,利用d31得到了一阶Ⅰ型EY^ωEY^ω-Ez^2ω(oo-e)准相位匹配蓝光二次谐波。在150C下,由114μJ抽运光,得到了52μJ,0.473μm倍频蓝光,对应于平均最大转换效率45.6%。制备了一阶和三阶周期分别为4.5μm和13.5μm的周期性极化铌酸锂。在EY^ωEY^ω-Ez^2ω(ee-e)准相位匹配0.473μm蓝光倍频中。150C下,分别得到了41.3%和19%的倍频转换效率。oo-e准相位匹配比传统的ee-e准相位匹配有较大的光栅周期,尤其在短波长区域倍频输出应用中,降低了周期性结构制作的困难,其较大的容许带宽在实验中提高了频率转换效率。实验结果表明了在周期性极化铌酸锂中准相位匹配倍频的偏振相关性。 相似文献
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宽带准连续光纤激光在周期极化铌酸锂中倍频特性的研究 总被引:3,自引:2,他引:1
双包层光纤激光器和非线性光学材料(如周期性极化的铌酸锂晶体,PPLN)相结合,开辟了实用性非线性光学器件的一个新领域。研究了准相位匹配周期性极化反转铌酸锂晶体对宽带准连续光纤激光倍频的温度特性和频谱特性。在理论上,从准相位匹配相位失配关系出发,推导了晶体温度与抽运源中心波长的关系以及温度响应带宽,并和已报道实验结果进行了比较,二者符合得很好。此外,还推导了倍频周期极化铌酸锂晶体对抽运基频光源的响应谱线带宽。在实验上,采用长度20mm,极化周期6.5μm,厚度0.5mm的周期极化铌酸锂晶体光纤激光器准连续宽带输出进行了倍频,获得了在不同控制温度下的倍频光光谱,并对此进行了详细分析。 相似文献
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周期性极化铌酸锂晶体中半非共线型宽带光学参变放大理论研究 总被引:1,自引:0,他引:1
基于周期性极化铌酸锂晶体(PPLN)的准相位匹配光参变放大过程,通过倾斜周期极化铌酸锂晶体中极化域(极化光栅)一定角度,实现了介于共线匹配方式和非共线匹配方式之间的一种半非共线型准相位匹配方式,并以该匹配方式下的各光矢量几何关系得出相位匹配曲线,找到在特定抽运光和信号光波长下能获得宽带增益放大的周期极化长度。并研究其极化倾斜角度与温度特性。模拟计算表明,在合适的角度与温度条件下,该方式可以532 nm抽运光抽运的信号光在800 nm和1064 nm处均获得宽带光参变放大。 相似文献
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I型准相位匹配周期性极化铌酸锂倍频蓝光输出 总被引:1,自引:1,他引:0
在周期为 14 .5 μm的周期性极化铌酸锂中 ,利用d3 1,得到了一阶I型EωYEωY-E2ωZ (oo-e)准相位匹配蓝光二次谐波。在 15 0℃下 ,由 114 μJ抽运光 ,得到了 5 2 μJ ,0 .4 73μm倍频蓝光 ,对应于平均最大转换效率 4 5 .6 %。制备了一阶和三阶周期分别为 4 .5 μm和 13.5 μm的周期性极化铌酸锂。在EωZEωZ-E2ωZ (ee -e)准相位匹配 0 .4 73μm蓝光倍频中 ,15 0℃下 ,分别得到了 4 1.3%和 19%的倍频转换效率。oo -e准相位匹配比传统的ee -e准相位匹配有较大的光栅周期 ,尤其在短波长区域倍频输出应用中 ,降低了周期性结构制作的困难 ,其较大的容许带宽在实验中提高了频率转换效率。实验结果表明了在周期性极化铌酸锂中准相位匹配倍频的偏振相关性。 相似文献
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一阶准相位匹配周期性极化铌酸锂倍频产生18 mW绿光连续输出 总被引:3,自引:1,他引:2
通过高压脉冲电场极化 ,制备了周期为 6 5 μm、长为 12mm、宽为 10mm、厚为 0 5mm的一阶准相位匹配周期性极化铌酸锂 ;由 1 1W连续 1 0 6 μmNd∶YAG激光器抽运 ,在 5°时产生了约 18mW、0 .5 32 μm的倍频连续绿光 ,其对应的二次谐波转换效率约为 1 6 % ,二次谐波的归一化转换效率约为 1 5 %cm- 1 W- 1 ,相当于 79%的周期性极化铌酸锂的理想非线性系数。测量了抽运光功率与倍频光功率的关系 相似文献
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利用掺杂浓度为5 mol%的掺氧化镁多周期极化铌酸锂晶体实现了高效单谐振的准相位匹配光参量振荡器,所使用的周期极化铌酸锂晶体有6个周期,且以1 μm为间隔,从26.5~31.5 μm. 该光参量振荡器以脉宽为150 ns,重复频率为10 kHz的声光调Q Nd∶YAG激光器为泵浦源,且泵浦光波长为1.064 μm. 通过控制晶体的温度(50~200℃)以及改变晶体的极化周期(26.5~31.5 μm),可由该光参量振荡器获得2.83~2.89 μm,3.10~3.38 μm,3.57~3.78 μm,3.95~4.12 μm, 4.28~4.46 μm,4.65~4.79 μm的闲频光连续调谐输出. 且当泵浦功率为8.15 W时,在闲频光输出波长为3.33 μm处,获得了最大输出功率2.17 W. 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 simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output. 相似文献
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The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper. 相似文献
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We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed. 相似文献
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Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell. 相似文献
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A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques. 相似文献
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Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing. 相似文献