Simulating electric field intensity distribution of LSPR based on gold nanobipyramids

Abstract Gold nanobipyramids (Au NBPs) are an important nanoparticle and widely used in micro-nano optical devices. Using finite difference time domain calculations, we studied the electric field intensity distribution of Au NBPs under the conditions of different aspect ratio, sharpness at both tips, excitation wavelength and incident polarization angle, respectively. The red plasmon shift of the extinction and the enhancement of the extinction peak can be achieved by changing the aspect ratio, the electric field intensity and the extinction have a similar tendency. Multilevel plasmon resonance and up to ten times the difference in the intensity of electric field will result from the sharpness of both tips. The electric field intensity will reach the maximum under the same conditions when the excitation wavelength is set to the wavelength corresponding to the peak of the extinction spectrum. The electric field intensity at both tips varies regularly with axisymmetric or central symmetric distribution by changing the incident polarization angle. This work is beneficial to the study and application of Au NBPs, and stimulates the advancement of other related researches.