共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
合成了一种能够形成单分子层膜,又具有很大分子二阶非线性极化率的有机分子材料——菧盐。对菧盐单分子层膜进行了光学二次谐波信号的测量,得到其分子二阶非线性极化率=1.2×10~(-27)esu。但它很难构成稳定的多层膜结构。本文首次报道菧盐/花生酸混合Langmuir-Blodgett(简计L-B)膜的制备及其非线性光学性能研究,混合膜就一般分子材料不能既具有较大的二阶非线性极化率,又能形成稳定的多层膜结构这一难题的可行性进行了探索。实验证明,混合膜是制备高倍频系数的稳定多层膜的可行措施之一。 相似文献
5.
通过测定在纯水和CdCl2 溶液亚相上十八胺单分子膜的平衡、循环π~A等温线及其动态弹性 ,发现在亚相中加入Cd2 + 可以使膜的液态相凝聚性增强 ,固态相凝聚性减弱 .液态的单分子膜在两种亚相上有较好的可回复性 ,而在固态膜中则不然 .这可归因于在水面上十八胺分子间可形成氢键 ,而在CdCl2 水溶液亚相上的十八胺则与Cd2 + 发生配位 ,形成了多配位络合物 ,两种情况下十八胺分子在高膜压区都会发生稳定的聚集 .静、动态弹性的比较表明 ,膜障的振动不利于十八胺分子与Cd2 + 间的配位作用 相似文献
6.
金属岛膜与金属颗粒膜的非线性光学效应 总被引:1,自引:0,他引:1
对金属岛膜和金属颗粒膜的非线光学效应进行了对比分析,讨论了膜厚、驱动场的偏振方及热处理等因素对光学二次谐波谐波的影响,提出了增加金属粒的二次谐波强度的方法,对表面增强曼散射和三阶非线性效应进行了简要的人。 相似文献
7.
8.
低强度微波电磁场作用下菠菜和烟草光合细胞叶绿素荧光动力学过程及光合色素系统的差异 总被引:1,自引:1,他引:0
在300MHz低强度微波电磁场作用下,菠菜和烟草叶片光合细胞叶绿素荧光动力学过程和光合色素呈现不同的变化.菠菜的荧光动力学参量F0和FVI/FV减小,FV/F0、ΔFV/T和FV/Fm升高;烟草的荧光动力学参量F0升高,FVI/FV没有明显变化,FV/F0、ΔFV/T和FV/Fm降低.在微波作用下,菠菜和烟草叶片的光合色素系统的变化也有差异,菠菜和烟草的叶绿素含量均降低,但菠菜的类胡萝卜素含量明显升高.这些结果表明,低强度微波电磁场使烟草叶片光合机构受到抑制,光合色素系统受到破坏,因而光合作用下降;菠菜则通过光合细胞的光合机构中PSⅡ活性中心异质性的转变和光合色素中类胡萝卜素含量的升高来适应微波辐射的环境,使光合作用维持在较高水平. 相似文献
9.
10.
采用实时测量光学二次谐波产生(SHG)和吸收光谱的方法对苯腙类有机分子NDA及一种新合成的经氰基团修饰的有机分子CNDA掺杂PMMA极化聚合膜的非线性光学性质进行了研究。实验中发现两种掺杂极化聚合膜的最佳电晕极化温度均低于它们的玻转温度,CNDA/PM-MA极化掺杂聚合膜的χ(2)较NDA/PMMA极化聚合膜的大。结合极化前和极化后吸收峰强度的变化,得到CNDA分子的非线性极化率β约为146×10-30esu。在撤离极化场后,CNDA/PMMA的二次谐波强度的弛豫也比NDA/PMMA的慢 相似文献
11.
12.
<正>In this paper,we theoretically investigate the effect of noise on the photoionization,the generation of the high-order harmonic and the attosecond pulse irradiated from a model He~+ ion.It shows that by properly adding noise fields,such as Gaussian white noise,random light or colored noise,both the ionization probabilities(IPs) and the harmonic yields can be enhanced by several orders of magnitude.Further,by tuning the noise intensity,a stochastic resonance-like curve is observed,showing the existence of an optimal noise in the ionization enhancement process.Finally,by superposing a properly selected harmonic,an intense attosecond pulse with a duration of 67 as is directly generated. 相似文献
13.
本文理论提出了一种利用超短紫外光源来增强阿秒脉冲强度的方法. 计算结果表明, 当适当的加入一束62nm或者125nm超短紫外光源到双色激光场时, 不仅高次谐波的截止能量被延伸了, 而且谐波的强度也比原双色场时有明显的增强. 尤其是当采用125nm光源时,谐波的强度被增强了2个数量级,并且形成了一个232eV的超长平台区. 最后通过叠加谐波次数从113次到170次可获得脉宽仅为43as的孤立阿秒脉冲, 其强度比原双色场情况下产生的阿秒脉冲增强了2个数量级. 相似文献
14.
An ion having hydrophobic parts can directly transport through the liposome bilayer without an ion channel and its transport
mechanism can be explained by the free-volume theory. This was confirmed by investigating the temperature effect on the transport
dynamics of organic cations through anionic liposome bilayers made of unsaturated and saturated lipids by using optical second-harmonic
generation (SHG) technique. This study provides useful information to design practical temperature-controlled drug delivery
systems. 相似文献
15.
利用超短的紫外光源来增强阿秒脉冲的强度 总被引:1,自引:0,他引:1
本文理论提出了一种利用超短紫外光源来增强阿秒脉冲强度的方法 .计算结果表明,当适当的加入一束62 nm或者125 nm超短紫外光源到双色激光场时,不仅高次谐波的截止能量被延伸了,而且谐波的强度也比原双色场时有明显的增强.尤其是当采用125 nm光源时,谐波的强度被增强了2个数量级,并且形成了一个232 e V的超长平台区.最后通过叠加谐波次数从113次到170次可获得脉宽仅为43 as的孤立阿秒脉冲,其强度比原双色场情况下产生的阿秒脉冲增强了2个数量级. 相似文献
16.
光学非线性LB膜的时间稳定性与光致漂白效应的关系 总被引:1,自引:0,他引:1
用光学二次谐波产生(SHG),拉曼散射和紫外-可见吸收光谱等方法研究了偶氮,苯腙及半花菁三种有机染料Z型Langmuir-Blodgett(LB)多层膜的时间稳定性问题,发现:随着放置时间的推延,其中LB膜的二次谐波产生信号强度下降,然后逐渐达到稳定;在高压汞灯光照射下,粉末样品中N=N(偶氮),C=N(苯腙),C=C(半花菁)键伸缩振动所对应的拉曼峰强度以及这三类染样在LB膜样品中对所应的生色团 相似文献
17.
B. Chen K.-X. Guo R.-Z. Wang Y.-B. Zheng B. Li 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,66(2):227-233
The nonlinear optical rectification
(OR) in the asymmetric double triangular quantum wells (DTQWs) is
investigated theoretically. The dependence of OR on the right-well
width of the DTQWs is studied, and the influence of the applied
electric field on OR is also taken into account. The analytical
expression of the OR susceptibility is analyzed by using the compact
density-matrix approach and the iterative method and the numerical
calculations are presented for the typical GaAs/AlxGa1-xAs
asymmetric DTQWs. The results show that the OR susceptibility
obtained in this coupled system can reach the magnitude of
10-3 m/V, 2-3 orders of magnitude higher than that in single
quantum systems. Moreover, the OR susceptibility is not a monotonic
function of the width of the right well, but has complex
relationship with it. The calculated results also reveal that an
applied electric field has a great influence on the OR
susceptibility. Applying an appropriate electric field to a
quasi-symmetric or symmetric DTQW can result in a larger OR
susceptibility as compared with that obtained in an optimal
asymmetric DTQW without electric field. 相似文献
18.
在含时密度泛函理论水平上研究了溶剂对硝基苯胺分子非线性光学性质的影响 .溶剂效应通过极化连续模型来研究 .首先采用极化连续模型在密度泛函理论水平上优化了硝基苯胺分子在溶剂中的几何结构 ,从而研究了溶剂引起硝基苯胺分子几何结构的变化 .然后采用极化连续模型在含时密度泛函理论水平上计算了不同溶剂中硝基苯胺分子的激发态能量和电偶极矩 ,并利用两态模型首次给出了不同溶剂中二次谐波振荡过程的一阶非线性超极化率的色散关系 .计算结果表明 ,极性溶剂对硝基苯胺分子的非线性光学性质有较大的影响 .在低的辐射场频率下 ,理论给出的一阶非线性超极化率的色散关系和实验结果符合得较好 .最后对所得结果从理论上给出了可能的解释并讨论了两态模型的可靠性 . 相似文献
19.
20.
H. Yildirim M. Tomak 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(4):559-564
The effects of asymmetry and the electric field on the
electronic subbands and the nonlinear intersubband optical
absorption of GaAs quantum wells represented by a P?schl-Teller
confining potential are studied. The potential itself can be made
asymmetric through a correct choice of its parameter set and this
adjustable asymmetry is important for optimizing the absorption. In
that way optimal cases can be created. We calculate the modified
wave functions and electronic subbands variationally. The linear and
the nonlinear optical intersubband absorption coefficients are
calculated. Numerical results for a typical GaAs quantum well are
presented. The nonlinear part of the absorption coefficient is
strongly modified by the asymmetry parameters while the electric
field affects it at smaller values of the parameters.
- 78.67.De Quantum wells 相似文献