Gucciardi P G, Lopes M, Déturche R, Julien C, Barchiesi D, Lamy de la Chapelle M
CNR-Istituto per i Processi Chimico-Fisici, sezione Messina, Salita Sperone, Contrada Papardo, I-98158 Faro Superiore, Messina, Italy.
Nanotechnology. 2008 May 28;19(21):215702. doi: 10.1088/0957-4484/19/21/215702. Epub 2008 Apr 23.
We have investigated the depolarization effects of light scattered by sharp tips used for apertureless near-field optical microscopy. Dielectric and metal coated tips have been investigated and depolarization factors between 5 and 30% have been measured, changing as a function of the incident light polarization and of the tip shape. The experimental results are in good agreement with theoretical calculations performed by the finite element method, giving a near-field depolarization factor close to 10%. The effect of depolarization has been investigated in polarized tip-enhanced Raman spectroscopy (TERS) experiments; the depolarization gives rise to forbidden Raman modes in Si crystals.
我们研究了用于无孔径近场光学显微镜的尖锐探针所散射光的去极化效应。对介电探针和金属涂层探针进行了研究，测量得到的去极化因子在5%至30%之间，其随入射光偏振和探针形状而变化。实验结果与采用有限元法进行的理论计算结果吻合良好，得到的近场去极化因子接近10%。在偏振尖端增强拉曼光谱（TERS）实验中研究了去极化效应；这种去极化在硅晶体中产生了禁戒拉曼模式。
