矽基微型光譜儀

Abstract

光譜學是研究電磁波與物質之間交互作用之學科，被頻繁地用於鑑定與分析物質。然而，由於目前常用的光譜儀體積太大且價格不斐，使其應用多被限制在科學研究領域。若能將光譜儀微型化並降低其生產成本，便能應用於人類的日常生活中，大大地改善人們的生活品質。 在本論文中，我們提出了兩種製作矽基微型光譜儀的方法。首先，我們利用半導體製程技術及兩種濕式矽蝕刻製程製作可撓式光柵，此光柵可以在矽的彈性限度內任意彎曲，曲面的光柵將同時具備色散以及聚焦的效果，能夠取代現行單光儀式光譜儀內使用兩面透鏡加上平面光柵的結構並簡化其光路，非常適合作為微型光譜儀之元件。另外，我們提出了一種基於耳語迴廊模態光學共振腔及石墨烯光偵測器的全新晶片型光譜儀結構，此光譜儀能夠達到奈米以下的解析度，且可以應用於任何頻段，極具發展潛力。

Spectroscopy is the study of the interaction between matter and radiated energy. With the ability to identify substances, it is widely used in research and industry. However, the key component, spectrometer, is too large and expensive which limits its availability and practicability. In this study, we proposed two ways to miniaturize the device and lower the cost, making the spectrometer portable and available for everyone. First, we fabricate silicon thin film grating using semiconductor technology and wet etching processes. The grating is bendable and is capable of dispersing and focusing the input beam. By installing the grating to a monochromator, the amount of optical components can be reduced, leading to a decrease in overall volume. Second, we provide a novel chip spectrometer design based on whispering-gallery mode resonators and graphene photodetector. The device can achieve sub-nanometer resolution due to the high-Q nature of the resonators. On the other hand, the wavelength range of the spectrometer can be customized without limit owing to the ultra-broad absorption spectrum of graphene. With these methods, spectrometer will become cheaper and smaller, and can be integrated into portable applications, which will open a new era for spectroscopy.