Investgation Of Surface Plasmon Resonance In Ag Nanowire Composite Metamaterials

Currently,the surface plasmon resonance(SPR)technology has evolved mainly in the sensor field,and plentiful SPR sensors designed based on principle of the technology have been commercially applied.In recent years,the localized surface plasmon resonance(LSPR)sensors based on nanomaterial technology are drawing increasing attention thanks to its advantages over traditional SPR sensors such as adjustable spectrum,significantly intensified local electric field and a better adaptation to the structural system of modern nanobiotechnology.This paper proposes a new metamaterial based on nanowire composite structure,and studies the SPR response when it is used as the sensitive film.Besides the P-polarized light excitation mode,the periodic nanowire array structure between the metal film and substrate can provide S-polarized light excitation mode,while a regular multi-layer film cannot.The analysis results of the finite element indicate that the SPR angular spectrum excited by Pand S-polarized light shows different SPR responses when the Kretschmann prism coupling structure of this material is excited by the 632.8nm incident light.The metal film thickness of the composite material mainly adjusts and controls the resonance strength.The filling ratio of the nanowire mainly adjusts and controls the resonance angle,and the internal electric field shows an interesting distribution.Finally,the above results are verified to some extent by experiments.This paper studies the availability of such metamaterials in SPR sensor field.The computing results show that the response of such metamaterials to the change of refractive index of the air medium reaches 41.67°/RIU.The sensitivity to the dielectric constant change of the medium around the nanowire reaches 2,500nm/RIU.The response of such metamaterials is one magnitude order higher than that of the traditional LSPR sensor samples to reflective index change.Its quality factor is 166.7/RIU.These results provide theoretical reference for design of the SPR sensor system with higher sensitivity and quality factor in application.