Position-controlled ultrahigh-Q nanocavities using single semiconductor nanowires in 2D photonic crystals ○ ダナン ビロウォスト 1,2 , 横尾 篤 1,2 , 谷山 秀昭 1,2 , 倉持 栄一 1,2 , 滝口 雅人 1,2 , 納富 雅也 1,2 NTT Basic Research Lab., NTT Corporation 1 , NTT Nanophotonics Center, NTT Corporation 2 , ○ M. D. Birowosuto 1,2 , A. Yokoo 1,2 , H. Taniyama 1,2 , E. Kuramochi 1,2 , M. Takiguchi 1,2 , and M. Notomi 1,2 E-mail: birowosuto.danang@lab.ntt.co.jp Most ultrahigh-Q nanocavities are fabricated by a combination of high-resolution electron beam lithography and dry etching. They also must be incorporated in the photonic crystal design prior the fabrication process. But recently, we can obtain the high-Q nanocavities through a post modification of photonic crystal (PhC) by employing scanning probe lithography 1 and filling the holes in the photonic crystals via water or polymer micro-infiltration 2 . However, beside these rewritable cavities, there is no technique with the ability to control the position of the cavity. Here we propose high-Q nanocavities based on a single semiconductor nanowire (NW) in a 2D photonic PhC, which are possible to engineer the position of the cavity through NW manipulations. We use a numerical modeling with 3D FDTD method to show that we can optimize large Q and small mode volume (V eff ) using a NW. Here we consider a NW with a refractive index (n) of 3.17 (InP) while the substrate has n of 3.48 (Si). The PhC design has a line defect with a width of 0.98a3 while lattice constant (a) is 440 nm. Initially, we set the radius of the holes (r) of 100 nm and the slab thickness (t) of 200 nm. We choose a square cross-section NW with a side length of 50 nm and a length of 3 m. Figure 1 shows the calculated field and the obtained Q and V eff for different designs. In (a), we simulated a simple design with a single NW on the top of the center of the line defect PhC resulting Q and V eff is 27,000 and 0.36 m, respectively. When we introduced an air slot in the center of the line defect, which matches the NW size, we improve Q and V eff , see (b). Then, we changed r = 127 nm and t = 150 nm so that Q increases by 5.5-fold while V eff decreases by 2-fold, see (c) in comparison with (b). Finally, by the discontinuity between the slot, the air and the NW, the cavity mode in the NW is strongly enhanced resulting Q of 1,450,000. Fig. 1. Calculated magnetic- |Hy| and electric-field |Ex| distributions for NW (a) on the top of a line defect of PhC, inside (b,c) a size-matched slot (width = 50 nm), and (d) 150-nm air slot. The values of r and t of (a) and (b) are 100 and 200 nm, respectively, while those for (c) and (d) are 127 and 150 nm, respectively. References 1 A. Yokoo, T. Tanabe, E. Kuramochi, and M. Notomi, Nano Letters, 11, 3634-3642 (2011) 2 F. Intonti et al., Appl. Phys. Lett., 89, 21117 (2006); Appl. Phys. Lett., 95, 173112 (2009) 第 73 回応用物理学会学術講演会　講演予稿集（2012 秋　愛媛大学・松山大学） Ⓒ 2012 年　応用物理学会 14p-B1-1 04-065 View publication stats View publication stats