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通过对聚片多畴LiNbO_3晶体倍频效应的研究,从实验上对Bloembergen等人所提出的准位相匹配理论进行了细致的检验。首先运用Maker条纹法在实验上直接测定了单畴LiNbO_3晶体在e~ω·e~ω→e~(2ω)非位相匹配下的倍频光强,并采用角度扫描和温度扫描方法,以获得满足准位相匹配条件时的不同片数的聚片多畴晶体的最大倍频强度,从而验证了聚片多畴晶体倍频相对光强与片畴数N成平方关系。在N<200时,取得令人满意的结果。把聚片多畴晶体的倍频光强与同质量同长度单畴晶体在o~ω·o~ω→e~(2ω)位相匹配下的倍频光强进行比较,其倍频强度提高一个数量级之多。最后,还从实验上讨论了倍频增强效应的结构敏感性。 相似文献
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INFLUENCE OF C+-IMPLANTATION DOSE ON BLUE EMISSION AND MICROSTRUCTURES OF Si-BASED POROUS β-SIC 下载免费PDF全文
Crystal Si were implanted with different doses of C+ from 1011 to 1017 cm-2 at an energy of 50 keV. β-SiC precipitates were formed by thermal annealing at 1050 ℃ for 1 h and porous structures were prepared by electrochemical anodization. Under the excitation of ultraviolet, the samples, with C+ dose ≥1015 cm-2 have intense blue emission which is stronger than the photoluminescence (PL) intensity of reference porous silicon (PS), and increases as C+ dose increases; the samples with C+ dose ≤1014 cm-2 show similar PL spectra to those of PS. The blue peak intensity in PL spectra is correlated with the TO phonon absorption strength of β-SiC in infrared absorption spectra. The transmission electron microscopy study shows that the blue peak is also correlated with the microstructures. Because porous β-SiC is nanometer in size, it is suggested that the quantum confinement effect be responsible for the blue light emission. 相似文献
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使用一块准周期LiTaO3光学超晶格晶体,利用准相位匹配技术,通过光参变产生与和频两个非线性过程,将一束532nm绿色抽运光转变成666nm红光与443nm蓝光。具体过程为,通过参变过程获得红色信号光和红外闲频光,再通过绿色抽运光与红外闲置光和频获得蓝光,两个过程在同一块准周期光学超晶格中实现,准周期超晶格的两个倒易矢量分别补偿这两个过程中的相位失配。抽运光的脉宽为40ps,重复频率为10Hz,在平均功率为0.5mW时,测得红光和蓝光功率分别0.15mW和16.6μW,转换效率达到34%和3%。这一方法,提供了一种用一块超晶格晶体同时获得三原色输出的有效途径。 相似文献
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Efficient Generation of Red and Blue Light in a Dual-Structure Periodically Poled LiTaO3 Crystal 总被引:2,自引:0,他引:2 下载免费PDF全文
We demonstrate the efficient generation of red light at 671nm and blue light at 447nm from a diode-pumped Q-switched 1342nm Nd: YVO4 laser together with a periodically poled LiTaO3 (PPLT) crystal. The sample used in this experiment is a dual-structure PPLT crystal with the period of 14.9μm for the second harmonic generation and that of 4.9μm for the third harmonic generation. The red and blue light, with the respective average power of 752 m W and 153 m W were obtained in a single path under an average fundamental power of 1.74 W, corresponding to the conversion efficiencies of 43.2% and 8.8%, respectively. These results indicate that the dual-structure PPLT can be used to construct a compact and efficient all-solid-state red-and-blue dual-wavelength laser. 相似文献
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报道了CuGeO3单晶在96GHz频率,1 4K温度下的电子顺磁共振(EPR)实验,测量了主轴g因子.导出了Cu2+离子在CuGeO3自旋佩尔斯系统中的混合d轨道基态波函数.采用近似自洽场方法计算了CuGeO3的主轴g因子.使实验结果得到了解释. 相似文献
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对于沿[0001]生长的LiNbO3单晶体,组分过冷形成的胞状界面和胞状组织进行了形态学的研究(组分过冷是由于操作上的原因在熔体中掺入了Al2O3而引起的),确定了胞状界面和胞状组织的基本形态。胞状界面是由相毗邻的三角锥组成,三角锥的稜锥面为{0112}面组,毗邻的三角锥体间存在沟漕,其中的熔体中浓集溶质。在长成的晶体中的胞状组织或是由{1210}面构成的其母线平行于[0001]方向的稜柱体,或是由溶质浓集的三{1210}面相交而成的三叉。实验观测证实了白丝、白点、云层及溶质尾迹是胞状组织的某种表现,而温度起伏是形成间歇式胞状组织的原因。通过胞状界面的形态研究,确定了形态干扰的某些具体形式,并证实了破坏界面稳定性的形态干扰与界面邻近流体的动量边界层的稳定性有关。文章最后讨论了高熔点氧化物晶体与金属晶体的胞状组织在形态上的差异,认为是由于两类物质的不同熔化熵而产生的。
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