Grating-assisted coupling enhancing plasmonic tip nanofocusing illuminated via radial vector beam
Lu Fanfan,
Zhang Wending,
Zhang Jiachen,
Liu Min,
Zhang Lu,
Xue Tianyang,
Meng Chao,
Gao Feng,
Mei Ting,
Zhao Jianlin
Affiliations
Lu Fanfan
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Zhang Wending
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Zhang Jiachen
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Liu Min
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Zhang Lu
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Xue Tianyang
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Meng Chao
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Gao Feng
MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin 300457, China
Mei Ting
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Zhao Jianlin
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Tip-enhanced Raman spectroscopy (TERS) is a very useful method to achieve label-free and super-resolution imaging, and the plasmonic tip nanofocusing plays a decisive role for TERS performance. Here, we present a method to enhance the nanofocusing characteristic of a plasmonic tip integrated in a grating near the tip apex. Simulation results show that the grating near the tip apex can significantly improve the electric field intensity of the nanofocusing field compared with a conventional bare tip, under axial excitation of a tightly focused radial vector beam. The electric field enhancement characteristic is quantified in relation with the groove number of grating, excitation wavelength, period of grating, and numerical aperture of the micro-objective (MO). These simulation results could be a good reference to fabricate a plasmonic tip for TERS applications, which is an effective way to promote the development of tip-enhanced near-field optical microscopy.
