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Updated: Dec 19, 2025
Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons
Published on: July 21, 2018
Determining the Interfacial Refractive Index via Ultrasensitive Plasmonic Sensors
Chao Zhan1, Bo-Wen Liu1,2, Zhong-Qun Tian1
1State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen 361005, China.
Abstract:
Plasmonic sensors are promising for ultrasensitive chemical and biological analysis. However, there are increasing experimental findings that cannot be well addressed by theoretical calculations, including the nonlinear dependence of the plasmonic peak wavelength on the refractive index (RI) and the ultrahigh sensitivity beyond the theoretical limit. The gap between experiments and theoretical calculations is that the bulk RI (BRI) used for calculation could be different from the interfacial RI (IRI) determining the electromagnetic response as a result of the interaction of molecules with the surface. But there is still no method to determine the IRI. Herein, we quantitatively determine the IRI by disentangling the surface RI (SRI) from the BRI. The obtained IRI can be directly applied in theoretical calculations to reliably reflect the experimental response and rigorously guide the design of plasmonic sensors. Moreover, it can be a fundamental dimensionless number to describe the light-matter interaction at the interface.
