| Summary: | 碩士 === 國立陽明大學 === 生醫光電研究所 === 104 === Surface plasmon resonance is a method commonly used to increase the sensitivity of optical sensors. The principle is based on the resonant excitation of surface plasmon polaritons subject to a refractive index variation of the medium surrounding the sensor. Here we propose the study of a device based on gold metallic diffractive gratings that enable the resonant excitation of surface plasmon polaritons. The goal is to design an optimized sensor by adjusting the opto-geometrical parameters of the structure. The optimal sinusoidal period of grating is realized between 300nm and 400 nm. A numerical and experimental evidence based on the detection of sucrose solution in different concentration are demonstrated in angular interrogation. The numerical modeling by Rigorous coupled-wave analysis is most typically applied to solve light scattering from periodic dielectric structures in Fourier-space. As for the experiment, we started by conducting study in air to ensure that the grating was working well. If the resonance phenomenon is able to be figured out in the result of air, the sample would be measured further in the liquid case. Once the resonance phenomenon in air was verified, we proceed further with measurements in the liquid phase. We studied four concentrations of 5, 10, 25 and 50 % in weight. The compact sensor shows interesting potential applications for on-chip detection of chemical or biochemical molecules.
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