Highly Directional Vertical Beaming of Photonic Crystal Coupled Cavities

초록

Gaussian-shaped far-field emission of low divergence, +/- 18.7 degrees, was obtained in a two-dimensional photonic crystal coupled cavity mode. Breaking of the electric field balance by elongated air holes allowed linearly polarized, directional far-field emission. The divergence was further reduced to +/- 7.5 degrees by increasing the size of the coupled cavity. Effects of the aspect ratio of elliptical air holes on quality factor and directionality are also discussed numerically. In addition, the coupling efficiency, 91%, of the proposed vertical emitter to the waveguide is obtained while quality factor is maintained as high as 1000. (C) 2010 The Japan Society of Applied Physics

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