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Journal of Nanomaterials
Volume 2015, Article ID 740984, 7 pages
Research Article

Butterfly-Inspired 2D Periodic Tapered-Staggered Subwavelength Gratings Designed Based on Finite Difference Time Domain Method

1School of Mechanical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
2School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
3Advanced Photonics and Plasmonics Division, A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, No. 16-16 Connexis, Singapore 138632
4Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India

Received 19 October 2014; Revised 23 December 2014; Accepted 18 January 2015

Academic Editor: Yaling Liu

Copyright © 2015 Houxiao Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The butterfly-inspired 2D periodic tapered-staggered subwavelength gratings were developed mainly using finite difference time domain (FDTD) method, assisted by using focused ion beam (FIB) nanoscale machining or fabrication. The periodic subwavelength structures along the ridges of the designed gratings may change the electric field intensity distribution and weaken the surface reflection. The performance of the designed SiO2 gratings is similar to that of the corresponding Si gratings (the predicted reflectance can be less than around 5% for the bandwidth ranging from 0.15 μm to 1 μm). Further, the antireflection performance of the designed x-unspaced gratings is better than that of the corresponding x-spaced gratings. Based on the FDTD designs and simulated results, the butterfly-inspired grating structure was fabricated on the silicon wafer using FIB milling, reporting the possibility to fabricate these FDTD-designed subwavelength grating structures.