以SU-8光刻胶作为波导芯层材料, 设计了基于金纳米粒子的局域表面等离子体共振(LSPR)波导传感器。根据Mie理论, 建立了金纳米粒子的消光模型, 理论分析了纳米粒子半径、待测物折射率等因素对局域表面等离子体共振曲线的影响。分析表明: 当待测液体折射率增大时, LSPR共振峰的位置发生红移。随着金纳米粒子半径的逐渐增大, 传感器灵敏度增加。共振吸收峰逐渐由单峰变为双峰, 其中一个峰位于520 nm波长附近, 主要由表面等离子体吸收造成; 另一个峰随金纳米粒子半径的增大而逐渐红移, 主要由表面等离子体散射造成。

A SU-8 polymer waveguide sensor based on local surface plasmonresonance( LSPR ) was designed. The extinction model of Au nanoparticles was established. Influence of Au nanoparticle’ radius and refractive index of analyte on LSPR curve was analysized. The theoretical analysis results show that the resonance wavelengths of LSPR sensor move to longwave direction when the refractive index of the analyte increases. With the increasing of Au nanoparticles’ radius, the sensitivity increases and the resonance absorption peak gradually changes from one peak to two peaks. One of the peaks locates near 520 nm wavelength, mainly caused by surface plasmon absorption. Another peak which is caused by surface plasmon scattering, moves to longwave direction gradually with the increasing of Au nanoparticles radius.