Biomedical Sensor using Spectral Interferometry-Based Surface Plasmon Resonance through Telecommunication Wavelength

• Main Authors: Ding-Zhang Tsai, 蔡定璋
• Other Authors: Shih-Hsiang Hsu
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/32175286048849366437

碩士 === 國立臺灣科技大學 === 電子工程系 === 104 === Biophotonics is a new and rapidly growing field in prevailing researches. Moreover, it has become one of the major developed projects of biomedical technology in recent years. The booming technology from the photonics and computing has not only promoted the life science development but also led the biotechnology progress to a new direction. In various sensing principles of biomedical systems, the optical property variation detected from the biochemical reaction process is an efficient, accurate, and popular approach. Surface plasmon resonance (SPR) is a physical phenomenon that happens between the interface of metal and non-conductive material. When a polarized light wave is entering a glass prism and satisfying the total internal reflection, the incident light will resonate with the thin metal film which is covered on the prism and generate the evanescent wave that penetrates into the dielectric layer. When the light is reflected by the prism at a specific angle or wavelength, the optical power will rapidly drop to minimum because of the resonant effect. In the meantime, the reflected light phase will also change dramatically. This specific angle and wavelength are named resonant angle and resonant wavelength, respectively. When the refractive index of the dielectric layer is changed, the resonant angle or resonant wavelength will shift, same as the reflected light phase. By applying these features onto biosensors, the real-time, high sensitivity and label-free detection could be demonstrated. Therefore, it has been extensively utilized in biosensing and immunochemistry for its efficiency in analyzing the small refractive index variation of detected materials. Among four common SPR modulation approaches, angle modulation, wavelength modulation, Intensity modulation and phase modulation, the phase modulation demonstrates the highest sensitivity. In order to retrieve the reflected light phase, the optical interference system is considered as a good implementation. In this thesis, a superluminescent emitting diode with the optical fiber communication bandwidth is utilized as the incident light source to generate the s-polarized light and p-polarized light in a common path. The p-polarization will interact and experience an additional optical path from SPR. Finally, a linear polarizer is implemented to combine two polarizations to illustrate the interference and produces a spectral interferometry-based SPR sensor. We successfully demonstrate the sensitivity of wavelength modulation and phase modulation of influenza and Mycobacterium tuberculosis DNA before and after the DNA probing. The sensitivity from DNA probes increases higher with the phase and wavelength modulations without immobilization.