標題: Plasmonic Coupling in Gold Nanoring Dimers: Observation of Coupled Bonding Mode
作者: Tsai, Chia-Yang
Lin, Jyun-Wei
Wu, Che-Yao
Lin, Pin-Tso
Lu, Tsan-Wen
Lee, Po-Tsung
光電工程學系
Department of Photonics
關鍵字: Surface plasmon;plasmonic array;nanoring;dimers;index sensing
公開日期: 1-三月-2012
摘要: We investigate the optical properties of gold nanoring (NR) dimers in both simulation and experiment. The resonance peak wavelength of gold NR dimers is strongly dependent on the polarization direction and gap distance. As the gold NR particles approach each other, exponential red shift and slight blue shift of coupled bonding (CB) mode in gold NR dimers for longitudinal and transverse polarizations are obtained. In finite element method analysis, a very strong surface plasmon coupling in the gap region of gold NR diners is observed, whose field intensity at the gap distance of 10 nm is enhanced 23% compared to that for gold nanodisk (ND) dimers with the same diameter. In addition, plasmonic dimer system exhibits a great improvement in the sensing performance. Near field coupling in gold NR dimers causes exponential increase in sensitivity to refractive index of surrounding medium with decreasing the gap distance. Compared with coupled dipole mode in gold ND diners, CB mode in gold NR dimers shows higher index sensitivity. This better index sensing performance is resulted form the additional electric field in inside region of NR and the larger field enhancement in the gap region owing to the stronger coupling of collective dipole plasmon resonances for CB mode. These results pave the way to design plasmonic nanostructures for practical applications that require coupled metallic nanopartides with enhanced electric fields.
URI: http://hdl.handle.net/11536/16133
ISSN: 1530-6984
期刊: NANO LETTERS
Volume: 12
Issue: 3
結束頁: 1648
顯示於類別:期刊論文


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