金属纳米颗粒LSPR光纤生物传感DDA方法研究

研究了金属纳米颗粒的局部表面等离子体共振(LSPR)行为,并讨论了其在光纤生物传感领域的应用.采用离散偶极近似(DDA)的方法,从理论上分析了金属纳米颗粒的尺寸、形状对其传感灵敏度的影响.计算结果显示,金属纳米颗粒的等离子共振吸收峰同时受到颗粒尺寸和形状的影响,但形状对其传感灵敏度的影响最为明显,计算结果与实验数据能较好地吻合.

Investigation of Noble Metal Nanoparticle LSPR Optical Biosensor Based on the DDA Method

Metals exhibit unusual optical, electronic, and magnetic properties at the nanometer scale. The optical response of noble metal nanoparticles is often characterized by the presence of a strong absorption band that is absent from the spectrum of the bulk metal. This is attributed to a resonance in the collective motion of the conduction electrons in response to an incident electromagnetic field and is called the localized surface plasmon resonance (LSPR). In this paper, the LSPR of noble metal nanoparticles is examined, and the discussion of its application in biosensing is followed. Based on the developed method, discrete dipole approximation (DDA), the dependence of the optical properties and the sensitivity of the metal nanoparticles on the size and shape is analyzed. The effects of the surrounding medium are also taken into consideration in the calcula-tioa The calculated results show that the plasmon extinction band depends on both the size and shape of the nanoparticles and the local environments. However, the influence of the shape to the sensitivity is most significant. The theoretical results are in good agreement with the experimental data.