表面等离子体耦合辐射(SPCE)是传统表面等离子体共振(SPR)的逆过程:当分子足够靠近金属薄膜表面时( < 200 nm),其受激辐射的能量可以耦合成SPR模式并定向辐射到棱镜中.由于具有场增强特性、高收集效率和优异的表面选择性, SPCE作为一种新的表面分析技术已经在荧光和拉曼光谱领域得到了有效的应用.本文采用光学互易定理简化传统SPCE的计算方法.通过计算,我们得到了SPCE一维和二维辐射功率密度分布,表面选择性,辐射角的波长色散特性,辐射角半峰宽与银膜厚度的关系.仿真结果与已报到的实验结果吻合良好,验证了该方法的有效性.
Surface plasmon coupled emission (SPCE) is a physical process opposite to conventional surface plasmon resonance (SPR) with Kretschmann configuration: if a molecule is close enough to the metal surface, the photons generated by excitation of the molecule will be coupled to the SPR mode that is then transformed into the far-field beam propagating at the resonance angle. SPCE serving as a powerful surface-selective analytical technique has been recently used in fluorescence and Raman spectroscopies, and it has several advantages such as repeatable field enhancement, high collection efficiency, and great surface selectivity. In this work, we simplified the simulation of SPCE based on the optical reciprocity theorem. We obtained the radiation patterns of the excited molecule with different orientations, the surface selectivity of SPCE, the wavelength dependence of the radiation angle, and the relationship between the full-width at half-maximum (FWHM) of the radiation angle and the thickness of a silver layer. These simulated results fit almost perfectly with the experimental results reported previously