We investigate the polarization property in tip-enhanced Raman spectroscopy by employing a radial plate consisting of four divided half-wave plates each with a different orientation of the slow axis. The radial plate provides both longitudinal (parallel to the tip axis; p-polarization) and lateral (perpendicular to the tip axis; s-polarization) of the electric field on the sample plane by selecting the proper polarization of the incident field. Single-walled carbon nanotubes, which have strong polarization dependence, are investigated with this polarization control. The radial breathing mode (RBM) and the G-band, which belong to different vibrational symmetries, show opposite polarization dependences. For both p and s-polarization studies, we used a new method for preparing silver probe with a silver particle at the apex. In this method, the probe has been coated with silver colloids by the mirroring reaction. We characterize the morphology of the silver probe by Scanning Electron Microscopy (SEM). A silver particle with diameter ～40 nm which is ideal for localized surface plasmon excitation in the visible wavelength range is formed at the tip apex with high reproducibility.
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