理论上研究了吸附在金纳米颗粒表面的CdSe量子点的双光子荧光增强效应。在偶极近似下, 全面地考虑了金纳米颗粒的存在造成的表面等离激元共振增强效应和以金纳米颗粒作为受体的非辐射能量转移效应, 给出了金纳米颗粒对量子点双光子荧光的增强因子。通过数值模拟, 给出了将贵金属纳米颗粒更有效地用于增强双光子荧光的方法, 即将贵金属纳米颗粒的表面等离激元共振峰调至激发波长处, 尽可能地增大激发光的表面等离激元共振增强效应。上述理论分析结果很好地验证了已经报道的实验结果。

Two-photon-excited fluorescence (TPEF) enhancement effect in CdSe quantum dot modified Au nanoparticle was theoretically investigated. TPEF enhancement factor was obtained in dipole approximation by taking surface plasmon resonance enhancement effect and nonradiative energy transfer to Au NP into account. An available method to achieve sufficient TPEF enhancement factor with noble metal nanoparticles was concluded from the analysis of numerical simulation. Greater TPEF enhancement effect will be obtained by adjusting the surface plasmon resonant peak of noble metal nanoparticles to the excitation wavelength. This theoretical analysis result was proved to be appropriate to the reported experimental results.