Study on the Transmission and the Field Enhancement of Bi-Rhombic Aperture Arrays Structure

Abstract

This paper presents a new bi-rhombic aperture arrays structure (BAAs) that exhibits high transmission and extraordinary field enhancement. Through numerical simulation and theoretical analysis, the surface plasmon resonance mode and a quasi-FP resonance mode within the structure are approved to enhance the optical transmittance effectively. The transmission spectrum and the charge distribution of the resonance mode shows that the gap size and the bi-rhombic aperture short axis have a significant effect on shiftting of the spectrum without damping the transmission peak of the wave, enabling the achievement of both high transmission and high field enhancement. The optimized structure achieved a transmittance of 85% and a maximum enhancement factor of 18000. Besides that, an ultra-wide spectrum transmission in the near to mid-infrared was attained by adjusting the aperture structure. At wavelengths larger than mid-infrared, the transmittance can avoid damping, and the adjusted device is primarily sensitive to the lattice constant in one- direction. These results suggest that the proposed BAAs has significant potential for various applications in nanophononics, infrared sensing, and biomedical imaging.

Keywords

• Surface plasmon resonance
• field enhancement
• extraordinary optical trasmission
• quasi-FP resonance
• surface-enhanced Raman scattering