## Transformation bending device emulated by graded-index waveguide |

Optics Express, Vol. 20, Issue 12, pp. 13006-13013 (2012)

http://dx.doi.org/10.1364/OE.20.013006

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### Abstract

We demonstrate that a transformation device can be emulated using a gradient-index waveguide. The effective index of the waveguide is spatially varied by tailoring a gradient thickness dielectric waveguide. Based on this technology, we demonstrate a transformation device guiding visible light around a sharp corner, with low scattering loss and reflection loss. The experimental results are in good agreement with the numerical results.

© 2012 OSA

## 1. Introduction

## 2. Device fabrication and morphological characterization

## 3. Theoretical analysis and numerical simulation

_{1}), PMMA layer (n

_{2}), silver film (n

_{3}), and glass substrate (n

_{4}) correspondingly.

*l-*th mode of the waveguide stays in this mode as along as thickness changes gradually, so we can transfer the surface profile (Fig. 3(d)) to effective index contour based on the thickness dependence of the TM1 mode (Fig. 4(c)). The mode index increases from 1.0 to 1.48 gradually as r decreases from 65 μm to 50 μm, where r is the distance from the top left corner. Therefore, a graded PMMA waveguide surrounding the corner is formed and its effective index is determined by gradient thickness.

## 4. Optical measurement results

## 5. Discussion and outlook

## 6. Conclusion

## Acknowledgment

## References and links

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12. | D. A. Roberts, M. Rahm, J. B. Pendry, and D. R. Smith, “Transformation-optical design of sharp waveguide bends and corners,” Appl. Phys. Lett. |

13. | M. Rahm, D. A. Roberts, J. B. Pendry, and D. R. Smith, “Transformation-optical design of adaptive beam bends and beam expanders,” Opt. Express |

14. | Z. L. Mei and T. J. Cui, “Experimental realization of a broadband bend structure using gradient index metamaterials,” Opt. Express |

15. | B. Edwards, A. Alu, M. G. Silveirinha, and N. Engheta, “Reflectionless sharp bends and corners in waveguides using epsilon-near-zero effects,” J. Appl. Phys. |

16. | M. Yan, W. Yan, and M. Qiu, “Cylindrical superlens by a coordinate transformation,” Phys. Rev. B |

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18. | H. Ma, S. Qu, Z. Xu, and J. Wang, “Wave-shape-keeping media,” Opt. Lett. |

19. | T. R. Zhai, Y. Zhou, J. Zhou, and D. H. Liu, “Polarization controller based on embedded optical transformation,” Opt. Express |

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21. | L. H. Gabrielli, J. Cardenas, C. B. Poitras, and M. Lipson, “Silicon nanostructure cloak operating at optical frequencies,” Nat. Photonics |

22. | E. Akmansoy, E. Centeno, K. Vynck, D. Cassagne, and J. M. Lourtioz, “Graded photonic crystals curve the flow of light: an experimental demonstration by the mirage effect,” Appl. Phys. Lett. |

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24. | T. Zentgraf, Y. Liu, M. H. Mikkelsen, J. Valentine, and X. Zhang, “Plasmonic Luneburg and Eaton lenses,” Nat. Nanotechnol. |

25. | R. K. Luneburg, |

26. | I. I. Smolyaninov, V. N. Smolyaninova, A. V. Kildishev, and V. M. Shalaev, “Anisotropic metamaterials emulated by tapered waveguides: application to optical cloaking,” Phys. Rev. Lett. |

27. | V. N. Smolyaninova, I. I. Smolyaninov, A. V. Kildishev, and V. M. Shalaev, “Maxwell fish-eye and Eaton lenses emulated by microdroplets,” Opt. Lett. |

**OCIS Codes**

(080.2740) Geometric optics : Geometric optical design

(230.7370) Optical devices : Waveguides

(160.3918) Materials : Metamaterials

**History**

Original Manuscript: March 27, 2012

Revised Manuscript: May 14, 2012

Manuscript Accepted: May 14, 2012

Published: May 24, 2012

**Citation**

Y. Wang, C. Sheng, H. Liu, Y. J. Zheng, C. Zhu, S. M. Wang, and S. N. Zhu, "Transformation bending device emulated by graded-index waveguide," Opt. Express **20**, 13006-13013 (2012)

http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-12-13006

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### References

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- V. N. Smolyaninova, I. I. Smolyaninov, A. V. Kildishev, and V. M. Shalaev, “Maxwell fish-eye and Eaton lenses emulated by microdroplets,” Opt. Lett.35(20), 3396–3398 (2010). [CrossRef] [PubMed]

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