Toyota Research Institute, Toyota Motor Engineering & Manufacturing North America, Ann Arbor, Michigan 48105, USA.
Opt Lett. 2010 Dec 1;35(23):3973-5. doi: 10.1364/OL.35.003973.
Here we show, analytically and numerically, that in a TiO(2) double-groove grating with two different groove widths per period attached on the SiO(2) substrate, the normally incident light couples to the +1st-order transmission with 96.9% efficiency and with a 50° diffraction angle that is larger than the SiO(2)-air interface critical angle. Modal analysis reveals that three propagating modes for the +1st diffraction order reach the grating back end in phase, while the corresponding propagating modes for the -1st and zeroth orders are added destructively at the grating end. Four optical devices based on this grating characteristic are numerically demonstrated.
在这里，我们通过分析和数值模拟的方法表明，在二氧化硅（SiO2）基底上附有两个不同槽宽的 TiO2 双槽光栅中，当光线以正常角度入射时，+1 阶传输的耦合效率可达 96.9%，且具有 50°的衍射角，大于 SiO2-空气界面的临界角。模式分析表明，+1 阶衍射的三个传播模式在光栅后端同相到达，而-1 阶和零阶的相应传播模式在光栅末端则是相消地叠加。我们还数值演示了基于这一光栅特性的四种光学器件。
