Analysis of hybridized surface plasmon resonance sensor with metallic nanoparticles for high sensitivity

In this paper, we propose a surface plasmon resonance (SPR) sensor with metallic nano-particles, which is based on the Kretschmann configuration for reflective-type measurement with enhanced sensitivity. The proposed structure is analyzed and compared with a conventional Kretschmann configuration by using 3D finite-difference time-domain method. The proposed structure is composed of semi-spherical nano-particles and a thin cladding layer. The evanescent field on the metallic structure is enhanced by the factor of 2.7, where the diameter of nano-particles, fill factor, and thickness of cladding film layer T_F are 30 nm, 50 %, and 40 nm, respectively. On the other hand, the enhancement of the evanescent field in the conventional SPR sensor is 1.7 for the same TF. Because of the enhanced evanescent field, the sensitivity of our proposed sensor is maximized to 137.1 degree/RIU while that of a conventional SPR sensor is 99.6 degree/RIU.