光纤Bragg光栅的饱和效应(英文)

光纤 Bragg光栅的饱和效应可引起二阶衍射 ,并使一阶衍射的峰值反射率下降 .本文利用折射率变化模型和耦合模理论 ,模拟了饱和情况下 Bragg光栅的一阶和二阶衍射谱 ,并讨论了饱和系数对一阶和二阶衍射的 Bragg波长和峰值反射率的影响 .数值模拟结果与参考文献中的实验结果相吻合 .

Phase, magnetism and thermal conductivity of glass ceramics from iron ore tailings

In order to develop the applications of ore tailings, the glass ceramics were prepared by using a conventional melting-quenching-sintering process. The phase component, microstructures, magnetic properties and thermal conductivities of the prepared glass ceramics were investigated by using X-ray diffractometer, scanning electron microscopy, vibrating sample magnetometer and thermophysical properties tester, respectively. The results show that orthorhombic olivine-type phase and triclinic sunstone-type phase formed when the glass was annealed at 700 oC, the concentration of olivine-type and sunstone-type phases decreased, the spinel-type cubic phase occurred and the amount increased when the annealing temperatures increased. The magnetic properties from the cubic spinel ferrites were detected in the glass ceramics, and the related saturation magnetization increased with the annealing temperature increasing. The porous glass ceramics with magnetic property showed much lower thermal conductivity, compared with the non-magnetic porous glass-ceramic and the dense glass-ceramics.

不对称双量子点系统中电压调控电磁诱导光栅研究

在不对称双量子点系统内,基于半导体量子相干效应对电压隧穿诱导光栅进行了研究。利用该系统内的电压隧穿效应,可以在两个不同的探测失谐位置处同时诱导出电磁感应透明,在此基础上通过调节相关参数改变吸收性质,弱吸收条件下的相位光栅强度尤其是一阶衍射强度在特定探测失谐位置处得到了增强。研究了隧穿电压、泵浦场强度、相互作用长度等参数对相位光栅效率的影响,结果显示,当同时增加泵浦场强度及电压隧穿率时,相位光栅的一阶衍射效率提高了50%左右。研究结果在量子信息处理、量子网络及光学成像等领域有潜在的应用价值。

不同涂层对微粗糙基底的极化光散射影响

为了研究涂层与基底间的极化光散射,应用一阶矢量衍射理论推导出基底极化双向反射分布函数(PBRDF)。将理论分析结果与实验数据比较并数值模拟分析了在相关和非相关模型下,SiO2和TiO2涂层厚度对PBRDF的影响。考察了不同折射率对基底PBRDF的影响。结果表明随着SiO2涂层厚度的增加,相关和非相关模型下的PBRDF逐渐靠近同时逐渐和裸基底重合,即能逐渐复现基底的粗糙度轮廓;随着TiO2涂层厚度的增加,PBRDF逐渐变大,即TiO2涂层对基底有较好的平滑作用。折射率的实部和虚部对PBRDF的影响相反。因此通过对不同涂层PBRDF进行测量和计算可以反演出基底的光学信息。

不同三能级系统中利用自发相干感应相位光栅研究

原子相干是控制光与原子相互作用的有效方法。本文对比研究不同三能级原子系统中自发辐射相干对电磁感应相位光栅的影响。结果发现,自发辐射相干可以显著增强一阶衍射效率,但是不同系统一阶衍射增强的程度不相同,与原子相干程度的依赖关系也有区别。对于Lamda和Ladder型系统,一阶衍射效率随自发辐射相干程度的增强而增强,其中Ladder型系统更明显。与此不同,对于V型系统,在自发辐射相干程度相对较小的区域出现一阶衍射效率的增强。