共查询到17条相似文献,搜索用时 93 毫秒
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光折变晶体Ce:BaTiO_3中的各向同性扇形散射 总被引:1,自引:0,他引:1
用一束e偏振的激光入射到一块掺CeBaTiO3晶体上,在出射方向上观察到了相同偏振的散射光扇。测量了散射光强度、建立时间与入射光波长、入射角度、入射功率的依赖关系,以及散射光强的角分布。对实验现象进行了解释。使用一组经过简化的基于二波耦合理论的方程进行了计算。在所得结果中,散射光强的角分布与实验值定量地符合;透射光强与入射角度、波长的关系能够反映出其变化趋势。 相似文献
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基于KNSBN:Cu晶体的光折变联合变换相关器 总被引:2,自引:0,他引:2
给出基于KNSBN:Cu晶体的光折变二波耦合联合变换相关器(TBJTC).以KNSBN:Cu晶体作为平方律转换器,将强度较大且携带参考图象和待识别图象联合频谱的信号光波与一强度较弱的相干平面参考光波同时输入于KNSBN:Cu晶体,通过光折变二波耦合过程的非线性能量转移,实现功率谱转换,进而实现相关识别.理论分析和实验结果表明,除输入输出外,该光学相关器无需CCD、LCLV等器件和相应的数字处理,是一个全光光学相关器. 相似文献
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用于双色全息存储(Fe,Cu)∶LiNbO3晶体的参量优化计算 总被引:1,自引:0,他引:1
在确定Cu在LiNbO3晶体中对应于365 nm和633 nm的激发系数、复合系数、光伏系数的基础上,采用龙格库塔(Runge-Kutta)数值方法理论研究了双掺杂(Fe,Cu)∶LiNbO3晶体的深浅能级的掺杂组分比、氧化还原状态对双色全息存储的记录灵敏度和动态范围的影响,并探讨了同时取得尽可能大的灵敏度和动态范围的晶体条件。结果表明,为了同时得到较大的记录灵敏度和动态范围,在实际应用中选用浅能级掺杂浓度为5.0×1025m-3,深能级掺杂浓度为3×1024~3×1025m-3之间的弱氧化晶体是合适的。 相似文献
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LiNbO3:Ru晶体的光折变特性研究 总被引:1,自引:1,他引:1
采用丘克拉斯基法生长了单掺杂的LiNbO3∶Ru晶体,并对其作氧化处理。实验研究了LiNbO3∶Ru晶体二波混频条件下光栅记录特性和波长的依赖关系;并且研究了氧化处理对其透射谱和光栅记录特性的影响。研究结果表明,LiNbO3∶Ru晶体的最佳记录波长为458 nm;氧化处理会增加LiNbO3∶Ru晶体对光的吸收,同时提高光栅记录的灵敏度和饱和衍射效率,表现了不同于LiNbO3∶Fe晶体的氧化态依赖特性。分析认为,LiNbO3∶Ru晶体的反常氧化态依赖特性可能是由于出现了电子通道效应的暗衰减机制,以及Ru存在多个价态所造成的。 相似文献
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用提拉法生长出3种不同浓度的双掺杂LiNb03∶Ce∶Cu晶体,测试双掺杂晶体的红外吸收光谱、紫外可见光吸收光谱和X射线衍射谱,掺杂相对浓度较高时,紫外吸收边向长波方向红移,X射线谱峰半峰值宽度变小.测试掺杂晶体在生长态和氧化态时的衍射效率,氧化态的衍射效率比生长态衍射效率高,但响应时间较长. 相似文献
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本文采用Cu2+斜方对称电子顺磁共振(EPR)参量的高阶微扰公式计算了晶体Cu1-xHxZr2(PO4)3中Cu2+的EPR参量(g因子和超精细结构常数A因子).计算结果表明,晶体Cu1-xHxZr2(PO4)3中[CuO6]10-基团的Cu-O键长分别为R||≈0.241 nm,R⊥≈0.215 nm,平面键角τ≈80.1°;由于对称性降低,中心金属离子基态2A1g(θ)和2A1g(ε)有一定程度混合,混合系数α≈0.995.所得EPR谱图的理论计算值与实验数据符合得很好. 相似文献
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从实验上和理论上对光折变晶体Bi_(12)SiO_(20)的电光效应和光电导效应进行了系统的研究,并进一步探讨了这两种效应中出现的非稳振荡现象. 相似文献
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An increase of the Nd~(3 ) doping concentration and an enhancement of the laser induced fluorescence in the single crystal of YAlO_3: (Lu~(3 ), Nd~(3 )) have been observed and are attributed to the size compensation effect. The low temperature (4.2K) fluorescence spectra indicate that the structure of the sharp lines arising from the radiative transitions of Nd~(3 ) ions is not changed by the existence of Lu~(3 ) ions, but the emission lines are inhomogeneously more broadened. Besides, it has been observed that the fluorescence due to the radiative transition from the Stark's sublevel R_2 of the metastable level ~4F_(3/2) to the sublevels Y_1 of the manifold ~4I_(11/2) decreases with decreasing temperature and the fluorescence arising from the transitions R_1→Y_1 is relatively increased. The experimental fact is qualitatively interpreted. 相似文献
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Youwen Liu Liren Liu De'an Liu Liangying Xu Changhe Zhou 《Optics Communications》2001,190(1-6):339-343
Nonvolatile photorefractive gratings have been recorded in LiNbO3:Cu:Ce crystals by using a He–Ne laser (633 nm) for recording and an argon ion laser (458 nm) for sensitizing. The sensitizing light increases the recording sensitivity by a−bexp(−Is/c) and saturation behavior will appear with high enough intensity of sensitizing light. The recording light increases the slope of η1/2 as a function of time during the initial stages of hologram formation by sublinear Ixr (x<1) and thus the recording light decreases the recording sensitivity. The dependence of saturation diffraction efficiency on the intensities of the recording and sensitizing light shows that there is a maximum dynamic range of the recording process. 相似文献
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Gansheng Li Jinhua Wu Ying Chen Jinfeng Chen Zhenzhu Shi Chunming Xiao 《Chinese Journal of Lasers》1993,2(1):91-96
The effect of melt pretreatment of Ce~(3 ): YAP and (Ce~(3 ) Nd~(3 )): YAP and their growth ambient gases on the quality of the crystals are described. Firstly, a superheating pretreatment of YAP melt is adopted in a nitrogen atmosphere containing a little oxygen to eliminate carbon; then the YAP melt is superheated in a reduction atmosphere to fully reduce Ce~(4 ) ions into Ce~(3 ) ions in the melt. Finally, in a growth atmosphere of pure nitrogen, high quality Ce~(3 ): YAP and (Ce~(3 ) Nd~(3 )): YAP single crystals with high Ce~(3 ) concentration with only few light scattering centers were grown. 相似文献
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R. Aguiar F. Sánchez C. Ferrater M. Varela 《Applied Physics A: Materials Science & Processing》1997,65(4-5):429-436
3 (100) single crystal substrates have been investigated. Poorly absorbed KrF irradiation leads to localized, deep, and unstable
damage on the crystal surfaces. By contrast ArF has been found to induce well-localized roughness and microcracks on LaAlO3(100) surfaces at fluences between 0.2 and 1.8 J/cm2. The material emission threshold was estimated at around 0.5 J/cm2 and cracks appeared above 1.4 J/cm2. The substrate surface state determines YBa2Cu3O7-x film growth, leading to morphological changes that have been related to a decrease in adatom mobility on the substrate. The
most striking feature is the drastic reduction in YBa2Cu3O7-x outgrowth density inside the irradiated areas. Irradiation has little effect on film crystalline properties. The main effect
on the electrical properties can be restricted to a decrease of critical current density up to a factor of 104, but such an important decrease is only observed in the most intensively irradiated substrates.
Received: 18 November 1996/Accepted: 12 June 1997 相似文献
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采用高温固相法在1100℃下合成了Eu3 掺杂的CdxZn1-xO发光材料。采用X射线衍射对所合成样品的结构进行了表征。分析了不同浓度Cd2 的掺杂对于样品发光及激发峰位置的影响。通过对荧光光谱的测试,表明Cd2 的引入使得体系的禁带宽度变窄,并且通过Cd2 掺杂浓度的变化,可以对样品的激发光谱峰值在380~410nm进行调制,样品的发光以520nm处的宽带发射为主,并没有明显的Eu3 的特征发射,表明基质与Eu3 之间的能量传递并不有效。在加入Li 作为电荷补偿剂之后,出现了来自Eu3 的特征发射,相应的发射光谱的发射主峰位于609nm。样品380~410nm的激发峰范围覆盖了紫外LED芯片的输出波长。因此,这种荧光粉是一种可能应用在白光LED上的红色荧光粉材料。 相似文献
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在确定Cu在LiNbO3晶体中对应于365nm和633nm的激发系数、复合系数、光伏系数的基础上,采用龙格-库塔(Runge-Kutta)数值方法理论研究了双掺杂(Fe,Cu):LiNbO3晶体的深浅能级的掺杂组分比、氧化-还原状态对双色全息存储的记录灵敏度和动态范围的影响,并探讨了同时取得尽可能大的灵敏度和动态范围的晶体条件。结果表明,为了同时得到较大的记录灵敏度和动态范围,在实际应用中选用浅能级掺杂浓度为5.0×10^25m^-3,深能级掺杂浓度为3×10^24~3×10^25m^-3之间的弱氧化晶体是合适的。 相似文献