Fiber-Optic Particle Plasmon Resonance Sensor:Characteristics of Waveguide Sensing Region and Extinction Spectra
| Autor: | Chen Chien-Hsing, 陳建興 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 In this study, we aim to develop highly sensitive optical refractive index sensors used in the biochemical sensing techniques. A novel fiber-optic particle plasmon resonance (FO-PPR) sensor is found to have a high sensitivity and allow label-free detection of biomolecules. The sensor sensitivity of FO-PPR can be enhanced by optical fiber sensing which is based on the evanescent wave via multiple total internal reflections and the extraordinary optical properties (known as particle plasmon resonance) of noble metal nanoparticles. In this research, we fabricated the trench type D-shaped fiber and cladding-off cylindrical fiber by femtosecond(fs) laser and CO2 laser micromachining system, respectively. In order to develop highly sensitive optical refractive index sensors, the waveguide sensing region of the fiber fabricated with laser machining must be analyzed. The quality analysis includes optical detection techniques and the mechanical strength detection techniques (tensile test). After quality analysis, we modified the gold nanoparticles on optical fiber sensors for detection of refractive index by the FO-PPR sensors. Furthermore, a fiber-optic spectrometer is used to measure the extinction spectra of FO-PPR sensors. Accordingly, we propose a methodology for parameter analysis of extinction spectra. This study first demonstrates the feasibility of fabricating a highly sensitive trench type D-shaped fiber sensor by the fs laser. The refractive index measurement results of sucrose solution of different concentrations show the sensor sensitivity can reach 9.62/RIU and the sensor resolution can reach 5.13×10-5 RIU for refractive indices in the range of 1.333 to 1.403. Afterwards, this study demonstrates the feasibility of fabricating a highly sensitive cladding-off cylindrical fiber by the CO2 laser and establishes a quality analysis method for laser processed fiber-optic sensors. After quality analysis, a perpendicular scanning path, a laser power of 4 W and a scanning speed of 9.45 cm/s was selected as the optimum processing parameter in this study. The refractive index measurements of sucrose solution at different concentrations show a sensitivity of 1.25/RIU and a resolution of 6.17×10-5 RIU pertaining to the sensor for refractive indices in the range of 1.333 to 1.383. Finally, we modified the gold nanoparticles on the cladding-off cylindrical fiber for detection of refractive index by the FO-PPR sensors. The fiber-optic spectrometer is used to measure the extinction spectra of FO-PPR sensors and analyze the parameters (resonance wavelength, absorbance(extinction) and absorption spectrum of full width at half maximum) involved in extinction spectra. The experimental demonstrates the high sensor sensitivity for the surface coverage in the range of 15.2% to 17.2% of FO-PPR sensors. Such a highly sensitive FO-PPR refractive index sensor can be developed to analyze of the relation between the refractive index sensor resolution and extinction spectra in order to optimize the sensor capability. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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