Effect of gap width on enhanced magnetic optical fields in metallic split ring resonators

Qi Shen,Zhuo Chen,Bo Hou,Zhen-Lin Wang

doi:10.1063/1.4770319

Abstract

We analyze the U-shaped metallic split-ring resonators (SRRs) aimed at creating highly confined and enhanced magnetic field in the near-infrared frequency range. At the magnetic resonance, the induced circulating current of the SRRs could lead to a strong enhancement of the surrounding magnetic field. Such a magnetic field enhancement is found to be dominated by the gap width between two SRR arms. By decreasing the gap width to 10 nm, the SRR is predicted to have a 3790-fold enhancement of the magnetic field at the resonance wavelength of 1340 nm.

Highlights

Metal nanoparticles have attracted a lot of attention because of their remarkable optical properties.[1,2] When localized surface plasmons (LSPs), i.e., the collective oscillations of conductionband electrons in metallic particles, are excited by light, the local electric fields around metallic nanoparticles could be greatly enhanced.[2]
It is interesting to note that when illuminated by azimuthally polarized beam, the electric field intensity enhancement in the gaps of the split ring resonators (SRRs) can be increased by more than one order of magnitude compared to that attained by linearly polarized beam.[12]
Enhanced magnetic response has been achieved through the interactions between magnetic atoms and other modes, there has been a lack of studies on the localized magnetic field enhancement of the magnetic atom itself

Summary

Introduction

Metal nanoparticles have attracted a lot of attention because of their remarkable optical properties.[1,2] When localized surface plasmons (LSPs), i.e., the collective oscillations of conductionband electrons in metallic particles, are excited by light, the local electric fields around metallic nanoparticles could be greatly enhanced.[2].

Results

Conclusion