本研究目標在發展一免標定(label free)、即時偵測(real time)及高敏感度(high sensitivity)的波導共振(Guided Mode Resonance)檢測晶片。 波導共振元件是具有次波長結構的光學濾波器，將入射光繞射入波導共振元件中，其中間的波導層會產生一傳遞光，最後沿原方向反射回去，此即為共振波(resonance wave)。此波導共振元件表面的光柵層環境折射率(refractive index)不同會使共振波長的位置改變。 本研究在傳統波導共振元件中加入一金屬層(metal layer)，使得元件的敏感度提升。透過FDTD(Finite-Difference Time-Domain)軟體來模擬與探討各種不同實驗參數所得到的結果，在模擬中，波導厚度、光柵深度為模擬中主要的兩個變數，最後從模擬中找出最佳的實驗參數。配合得到的參數，利用半導體製程技術作出晶片，最後再利用晶片作各個不同折射率的鹽水溶液量測，用來找出晶片的敏感度。 本研究中實際製作與量測出傳統GMR晶片與含金屬層的GMR(本研究中稱為MaGMR：Metal-assisted Guided Mode Resonance)晶片其敏感度的大小，敏感度的單位為nm/RIU，指在單位折射率下共振波長偏移量的大小。從模擬結果中，得到GMR晶片敏感度為136nm/RIU，MaGMR晶片敏感度為338.5nm/RIU；從量測結果中，得到GMR晶片敏感度為103.3nm/RIU ，MaGMR晶片敏感度為376.7nm/RIU。模擬與量測結果都顯示出MaGMR晶片的敏感度優於GMR晶片。 The target in this study is to develop a Guided Mode Resonance (GMR) biosensor which is label free, real time and high sensitivity. The GMR sensor is an optical filter which has subwavelength structures, by launching the incident light into the waveguide structure, a specific wavelength light will be diffracted into the waveguide layer, finally reflected back along the original direction, which is called the resonance wave. The change of refractive index above the GMR structure causes a shift of the resonant wavelength. In this study, we add a metal layer to the traditional GMR sensor and increase its sensitivity to the changes of refractive index above the GMR structure. Through the FDTD(Finite-Difference Time-Domain) software to simulate the optical prosperities of metal assisted guided mode resonance(MaGMR) sensor and optimize the sensitivity. In the simulations, the thickness of the waveguide and the grating depth are the two major variables. A chip according to the optimized simulation parameter is fabricated and also demonstrated. In this study, the measurements of sensitivity are compared with a traditional GMR sensor. The unit of sensitivity is nm/RIU which means the value of the resonant wavelength shift under one unit of refractive index. In the simulation results and measurement results, the sensitivity of MaGMR is 338.5nm/RIU and 376.7nm/RIU respectively the sensitivity of GMR is 136nm/RIU and 103.3nm/RIU respectively, both the simulation and measurement results show that the sensitivity of MaGMR sensor is better than GMR sensor.
