Graphene and few-layer graphite probed by second-harmonic generation: Theory and experiment
Graphene and few-layer graphite probed by second-harmonic generation: Theory and experiment
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DOI：
10.1103/physrevb.82.125411
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发表时间：
2010-09-08
影响因子：
3.7
通讯作者：
van Driel, Henry M.
中科院分区：
文献类型：
--
作者：
Dean, Jesse J.;van Driel, Henry M.
我们已经测量了二次谐波产生（SHG）从石墨烯和其他石墨薄膜，从两层到块状石墨，在室温下，所有的样品都安装在300 nm的氧化层的Si（001）衬底。与800 nm，150 fs的基本脉冲，各向异性的响应被记录为p-，s-和对角偏振的基本和二次谐波光束的组合作为样品被旋转约其法线。石墨烯样品显示SHG签名仅与裸衬底的SHG签名略有不同，裸衬底显示具有四重旋转对称性的SHG。所有其他层状系统显示三重对称性，虽然各向同性的各向异性的响应的比例随层数而变化。提出了一种基于线性光在分层介质中传播的模型，该模型包括界面偶极源和体四极源。我们表明，从所有分层样品的数据可以理解在众所周知的线性光学性质，裸基板和四个独立的，复杂的非线性偶极极化率张量元素的石墨烯/空气界面的SHG响应。
We have measured second-harmonic generation (SHG) from graphene and other graphitic films, from two layers to bulk graphite, at room temperature; all samples are mounted on a 300 nm oxide layer of a Si(001) substrate. With 800 nm, 150 fs fundamental pulses, the anisotropic response was recorded for combinations of p-, s-, and diagonally polarized fundamental and second-harmonic beams as the samples were rotated about their normal. Graphene samples display SHG signatures only slightly different from that of the bare substrate which shows SHG with fourfold rotational symmetry. All other layered systems show threefold symmetry, although the ratio of isotropic to anisotropic response varies with the number of layers. A model based on linear light propagation in layered media with interface dipole and bulk quadrupole SHG sources is presented for the analysis. We show that data from all layered samples can be understood in terms of well-known linear optical properties, the SHG response of the bare substrate and four independent, complex nonlinear dipole susceptibility tensor elements of the graphene/air interface.