排序方式: 共有19条查询结果,搜索用时 15 毫秒
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应用密度矩阵方程计算了四能级原子系统中三阶非线性极化率随信号光和探针光频率失谐的变化关系。结果表明,由于量子干涉对信号光强度的敏感性,使四能级原子介质的交叉Kerr非线性作用大大增强,与三能级系统相比,四能级原子介质的Kerr非线性系数可增强两个数量级。 相似文献
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以D-甘露糖和2,4-二羟基二苯甲酮(UV-O)为原料,合成了新型的紫外线吸收剂(3-羟基-4-苯甲酰基)苯基-2,3;4,6-二-O-亚环己基-D-β-吡喃甘露糖苷(UV-O-DHM),其完全分解温度可达372.6 ℃,具有很好的热稳定性。 将UV-O-DHM均匀地掺入聚乳酸(PLA)的二氯甲烷溶液中,通过静电纺丝制得了可生物降解的抗紫外线PLA超细纤维膜。 采用扫描电子显微镜观察了纤维形貌,纤维的粗细均匀,直径为3~4 μm,且纤维表面有均匀的纳米孔结构。 随着PLA纤维中UV-O-DHM浓度的增大超细纤维的紫外辐射透过率降低。 当UV-O-DHM的掺入量为1.1%时,在230~350 nm范围内,透过率基本接近于0,同时在365~380 nm的紫外光范围内抗紫外辐射效果明显优于同等条件下的UV-O/聚乳酸纤维。 相似文献
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We propose a terahertz hybrid metamaterial composed of subwavelength metallic slits and graphene plasmonic ribbons for sensing application. This special design can cause the interaction between the plasmon resonances of the metallic slits and graphene ribbons, giving rise to a strong coupling effect and Rabi splitting. Intricate balancing in the strong coupling region can be perturbed by the carrier concentration of graphene, which is subject to the analyte on its surface. Thereby, the detection of analyte can be reflected as a frequency shift of resonance in terahertz transmission spectra. The result shows that this sensor can achieve a theoretical detection limit of 325 electrons or holes per square micrometer. Meanwhile, it also works well as a refractive index sensor with the frequency sensitivity of 485 GHz/RIU. Our results may contribute to design of ultra-micro terahertz sensors. 相似文献
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A plasmonic cavity filled with active material is proposed to explain optical switching. Optical properties, including transmission, response time, and field distribution of on/off state, are numerically investigated. We demonstrate that such a gain-assisted plasmonic structure can achieve optical switching in the nan- odomain and shorten the switching time to the subpicosecond level. Our results indicate the potential application of the proposed structure in optical communication and photonic integrated circuits. 相似文献
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在高中数学的教育教学中,如何适应高考从能力立意到素养导向的转变,日常试题命制是重要一环.本文以一道圆锥曲线解答题的命制为例,分享试题的命制过程及感悟. 相似文献
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受激布里渊散射效应具有光谱线宽窄、频率稳定和增益方向敏感等优点,常用于激光器,慢光产生和微波光子滤波器等.本文基于As2S3硫系玻璃、以SiO2为衬底设计了一种亚微米尺寸的带空气狭缝倒置结构脊型波导结构,具有高达8.22×104 W–1·m–1的后向受激布里渊散射增益系数.研究显示在该结构的同种光学和声学模式下,更小的声光场有效模场面积具有更高的后向受激布里渊散射增益系数.还分析了硫系玻璃的光学损耗对后向受激布里渊散射的影响,发现当波导长度超过最优值后,斯托克斯光波功率开始下降,而增大泵浦光功率不仅可以提高斯托克斯光波功率的极大值,同时还会增大波导长度的最优值.当所输入的泵浦光功率为20 mW时,受激布里渊散射增益达到100 d B波导长度仅需要2 cm,这非常有利于光子器件的片上集成. 相似文献