高繞射效率光柵元件在立體視覺的應用研究

本研究利用了二次的黃光微影及磁控濺鍍機製造了具有高深寬比的高深寬比光柵，並且量測其繞射光的效率、偏振以及角度。為了評估高深寬比光柵與一般平面光柵繞射特性的差別，製做了平面光柵。使用基於時域有限差分法的模擬軟體建立高深寬比光柵與平面光柵的模型，分別計算它們的繞射效率與繞射角度。實驗結果發現，高深寬比光柵的兩個一階繞射效率接近300%，並且這個光柵不受到入射光偏振方向的影響。實驗的繞射光的效率、偏振以及角度吻合模擬結果。此高深寬比光柵的300%繞射效率高於以往的繞射元件。模擬的場圖指出位於高深寬比壁外側光的建設性干涉增強以及位於高深寬比壁內外側光的破壞性干涉衰弱，大幅地增加一階繞射光束的效率。這個高效能的高深寬比光柵能夠用於馬竇氏鏡(Maddox Rod)、空間頻率視覺(spatial frequency vision)、虛擬實境(virtual reality)、光譜儀(Spectroscope)和3D電視(3D television)。

This work fabricates a High aspect ratio ITO grating using photolithography and magnetron sputtering deposition. The efficiency, polarization and angle of one of the two 1st-order diffraction beams are measured. A plane grating is fabricated to evaluate the diffraction characteristics of the High aspect ratio grating. A simulation software based on the finite-difference time-domain method is used to build the models of the high aspect ratio and plane gratings, and calculates the efficiencies and angles of their 1st-order diffraction beams.The two 1st-order diffracted beams in the grating beams have the same efficiency of approximately 300 %. The related simulation reveals that the high diffraction efficiency arises from the enhanced constructive interference between the lights at the two outer sides of each of the high aspect ratio structures and the weakened destructive interference between the lights at the inner and outer sides of that structure. The high aspect ratio grating is independent of the polarization of incident light. As a result, the high-performance high aspect ratio grating can be used in Maddox Rod, spatial frequency vision, virtual reality, spectroscope and 3D television.