學術研究
畢業論文
利用表面電漿共振增強 Goos–Hänchen 位移現象量測折射率變化
姓名 : 涂譽馨
指導教授
郭倩丞
論文摘要
This work adopted the concept of Goos-Hänchen effect into the Surface Plasmon Resonance biosensor. The experimental design is based on the theory of the Polarization of Light, Goos-Hänchen effect, Surface Plasmon Resonance and Interferometry. And a new parameter, Kaisa, is introduced and defined.
In the experimental design, a laser beam with both TE and TM polarization mode serves as the incident light source arriving at the Kretschmann Configuration. Since the Surface Plasmon Resonance introduce different Goos-Hänchen shifts to the laser beam with TE and TM polarization mode, the incident laser beam is split into two beams with TE and TM polarization mode respectively. Moreover, there is a slight spatial shift between them. After the Krestchmann Configuration a Glan-Thompson Polarizer is placed to allow only the beam with TE or TM polarization mode to pass, and create the component on the same direction for both beam to interfere with each other. At last the detector will measure the power of the beam with TE and TM polarization mode respectively and the power of the interference term. The new parameter, Kappa, is then defined as the power of the interference term divided by two times of the square value of the product of the power of the beam of TE and TM polarization mode.
According to the theoretical calculation and simulation, the Figure of Merit (FoM) of the power of the beam with TM polarization mode, which is commonly used as the parameter for Surface Plasmon Resonance biosensor testing is 37.12, meanwhile, the FoM of Kaisa is 114.67, indicating increasing the resolution of the biosensor by 3.09 times. In practice, the sucrose solutions are selected as the testing sample, with the concentration of 0%, 1.25%, 2.5%, 5% and 10%, and the corresponding refractive index will be 1.33299, 1.33478, 1.33659, 1.34026 and 1.34783 respectively. The Limit of Detection (LoD) of the system is able to reach 1.05×10^(-3) RIU (Refractive Index Unit).