本研究利用自我複製式光子晶體(autocloned photonic crystal)設計並製造出一偏振分光鏡(polarization beam splitter)，並探討結構參數對光子能隙之影響。自我複製法為結合微影及薄膜沉積之製造多维光子晶體技術。本設計與傳統偏振分光鏡不同的是，元件為平面且可於垂直入射工作。本研究使用有限差分法(FDTD method)模擬其穿透光譜圖及頻帶結構圖。從模擬結果可發現在某些波段下垂直偏振(TE)處於能隙(band gap)而平行偏振(TM)處在通帶(pass band)。因此可有效的在垂直入射時分開兩種偏振態。我們使用TiO2 及SiO2 堆疊29 層之二維波狀結構，並且利用抗反射 膜(anti-reflection coating)之設計來消除波紋(ripples)。此PBS 之工作範圍約為200 nm (1100 nm~1300 nm)，消光比(extinction ratio)為139。 IA novel design of photonic-crystal polarization beam splitter was demonstrated. The beam splitter is a 2-dimensional wavy structure of multilayer thin films consisted with a number of alternate high and low refractive indices transparent dielectric layers deposited sequentially on a periodic structured substrate. The fabrication of the photonic-crystal polarization beam splitter is based on the autocloning method which integrated the techniques of lithography and thin-film deposition. Different from the traditional polarization beam splitters, the photonic-crystal polarization beam splitter is a flat type of polarizer working at normal incident angle. The transmission and reflectance spectra were analyzed using finite-difference time-domain method (FDTD). From the analysis result, we found the photonic bandgap was happened at transverse electric (TE) mode and the passband at transverse magnetic (TM) mode. So, the photonic crystal polarization filter can separate TE mode and TM mode effectively at normal incident angle. To fabricate the polarization beam splitter, we have chosen TiO2 and SiO2 as high and low refractive index materials and deposited 29 layers of wavy structure. The AR (anti-reflection) coating has been applied to reduce ripples. The working wavelength range of the PBS is about 200 nm (1100 nm~1300 nm) in infrared region and the extinction ratio is 139.
