A Nanostructure with Dual-Band Plasmonic Resonance and Its Sensing Application

Abstract

A nanostructure plays a crucial role in surface plasmon resonance applications. In this paper, a new nanostructure with strong dual-band surface plasmonic resonance is proposed. The nanostructure resonant behavior in terms of wavelength position, magnitude and bandwidth was developed, and its ability to detect refraction indices, particularly for solution concentration determination, is theoretically studied by using the integration commercial code CST Studio Suite. A high enhancement factor 232 times that of common dipoles and dual bands (wavelengths = 778 and 1118 nm) are achieved from the structure. The dependence of resonance on the environmental index with different increments and detection effects on three solutions are further investigated. The results demonstrate that the resonant wavelength linearly increase with increased index, and resonant peak decrease. Meanwhile, the bandwidth of the resonance spectrum is broadened by the growth of index. The sensitivity is more than 950 nm/RIU and the resolution is about 10-3 refractive index units (RIU) when we detect the environmental index by the resonant wavelength. However, the sensitivity is about 231307 (V/m)/RIU by using the resonant peak for detection. This study may be useful in the fields of biosensors, solar batteries, microstructure devices, and measurements.

Keywords

• Optics
• Surface plasmons
• Sensor
• Plasmonics
• Nanostructure