Rogers Al-Aakhir A, Samson Scott, Kedia Sunny
University of South Florida, Department of Electrical Engineering, 4202 E. Fowler Ave, Tampa, Florida 33620, USA.
J Opt Soc Am A Opt Image Sci Vis. 2009 Dec;26(12):2526-31. doi: 10.1364/JOSAA.26.002526.
A technique was developed to couple near-field evanescent waves into observable diffraction orders in the far-field region. This investigation was of two gratings that have a 1.0 microm grating period in glass and 1.1 microm in silicon and are individually subwavelength, but when coupled together yield an 11.0 microm effective grating period. This effective grating period is not subwavelength to a 1.550 microm infrared incident source and exhibits higher diffraction orders. Optimum evanescent wave coupling efficiency was simulated by varying the grating thickness and the grating separation between the subwavelength gratings. This proposed evanescent wave coupling concept is being investigated for use in a bulk silicon MEMS accelerometer.
开发了一种将近场倏逝波耦合到远场区域中可观测衍射级的技术。这项研究涉及两个光栅，一个在玻璃中的光栅周期为1.0微米，另一个在硅中的光栅周期为1.1微米，它们各自的尺寸都小于波长，但耦合在一起时会产生11.0微米的有效光栅周期。这个有效光栅周期对于1.550微米的红外入射源来说不是亚波长的，并且会展现出更高的衍射级。通过改变亚波长光栅之间的光栅厚度和光栅间距，模拟了最佳倏逝波耦合效率。目前正在研究这种提出的倏逝波耦合概念在体硅微机电系统加速度计中的应用。
