贵金属纳米颗粒的LSPR峰对周围介质的变化十分灵敏，基于这一原理可对周围介质进行探测。本文利用吸收性介质中的Mie理论分析球形Ag纳米颗粒在吸收性介质中的光谱和探测性能。研究结果表明，当介质复折射率的虚部较小时，其对颗粒光谱和探测性能的影响可以忽略；随着虚部的增大，光谱会出现较大变化，并且颗粒的探测性能逐渐降低；当虚部大于某一值后，颗粒的LSPR峰消失，无法再利用这一原理进行探测。

The LSPR spectroscopy of Ag nanoparticles is sensitive to the changes of surrounding medium, which enables the nanoparticles to serve as plasmonic nano sensors. In this paper, the spectroscopy and sensing performance of nanosphere are investigated by employing the Mie theory in absorbing medium. The results show that when the imaginary part of the complex refractive index of the medium is small, its influence on the LSPR spectroscopy and the sensing performance can be neglected; The LSPR spectroscopy changes greatly, and the sensing performance of nanosphere decreases with the increase of the imaginary part. The LSPR peak disappears when the imaginary part of surrounding medium is large enough, then LSPR spectroscopy is not suitable for sensing.