Inhomogeneous Electromagnetic Field Polarization Enhancement Of Gold Nanoparticles Induced By Fiber Optics Polymer Taper

This paper introduces the process of optical fiber taper fabrication and the attachment of gold nanoparticles. Besides, we simulate the enhanced effect of gold nanoparticles in inhomogeneous electromagnetic field using FDTD method. And the electromagnetic field is excited by an optical fiber taper. Firstly, the electric field distribution of different taper-tip shapes is analyzed in this paper, to get an optimal taper-tip shape for the nanoparticles' polarization. Secondly, the affecting factors of polarization for single nanoparticle are taken into consideration, such as the radius of gold nanoparticle and its distance to the taper-tip. Finally, taking two gold nanoparticles for example, we also explore the polarization effect of multi-particles at different position. We conclude that: For single nanoparticle, when the taper-tip shape is parabola (X=|Z|0.3), the gold nanoparticles radius is 15 similar to 25nm, and the distance to the taper top is 10nm, the enhancement of electric field is most significant. For multi-particles, when orientation is perpendicular to the electric field direction, the enhancement is most significant. The simulation results of this paper will provide a theoretical support for the fabrication of the optical fiber taper and the attachment of precious metal nanoparticles.