表面等离子激元诱导的手性分子和角动量光束相互作用研究

发布时间：2018-06-05 11:53

本文选题：光的轨道角动量 + 表面等离子激元　；参考：《北京理工大学》2015年硕士论文

【摘要】：手性分子能展现出光学活性,它们对光的圆偏振度或螺旋性很敏感。通常人们利用这一特性,通过测量手性分子对左旋和右旋偏振光吸收的差,也就是圆二色性(CD),来衡量手性分子的手征特性。这些研究说明光学活性与光子的自旋角动量(SAM)具有内在联系。最近,人们认识到光子除了具有偏振特性之外,还可以携带轨道角动量(OAM)。那么OAM这个自由度的增加对CD是否会产生影响呢?基于这个问题,最近人们也做了很多研究,但得出了矛盾的结论:一些研究预测在电偶极子近似下这种相互作用是可以观察到的,而另一些研究认为没有这种效应。考虑到上述争论问题,本论文对轨道角动量光束与手性分子/金属纳米颗粒复合结构相互作用进行了实验研究,探讨金属纳米颗粒激发的表面等离激元能否诱导出轨道角动量和手性分子的相互作用。为此,我们设计了两个实验来观察这种现象。一个是测量手性分子/金属纳米颗粒复合结构对正负轨道角动量光束CD的差,另一个是直接探测样品对正负轨道角动量光束吸收差。不幸的是,两种方法均没观测到轨道角动量光束与手性分子/金属纳米颗粒复合结构相互作用的信号。我们分析了实验条件和理论计算的差别,澄清了产生这一矛盾的根源,为下一步实验观察这种相互作用指明了方向。
[Abstract]:Chiral molecules exhibit optical activity, which are sensitive to the circular polarization or helicity of light. It is usually used to measure the chiral molecules' chiral properties by measuring the difference in the absorption of left-handed and dextral polarized light by chiral molecules, that is, circular two color (CD). These studies show the spin angular motion of the optical activity and the photon. SAM has an inherent connection. Recently, people have realized that photons can also carry orbital angular momentum (OAM) in addition to polarization properties. Then whether the increase of the degree of freedom of OAM affects the CD? Based on this problem, a lot of research has been done recently, but a contradictory conclusion is drawn: some studies predict the electric dipole. In this paper, the interaction between orbital angular momentum beam and chiral molecule / metal nanoparticle composite structure is studied in this paper, and the induced surface plasmon excited by nanomi particles can be induced to be induced. The interaction between orbital angular momentum and chiral molecules. To this end, we have designed two experiments to observe this phenomenon. One is to measure the difference between the positive and negative orbital angular momentum beam CD of a chiral molecule / metal nanoparticle composite structure, and the other is to directly detect the difference in the absorption of the positive and negative orbital angular beam. Unfortunately, two methods are all No signal of interaction between orbital angular momentum beam and chiral molecular / metal nanoparticle composite structure was observed. We analyzed the difference between experimental and theoretical calculations, clarified the origin of the contradiction, and pointed out the direction for the next experiment to observe the interaction.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O436.3;TB383.1

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