Bulk optical metamaterials assembled by microfluidic evaporation

We present high refractive index optical metamaterials assembled via a microfluidic evaporation technique. This technique enables fabrication of truly three-dimensional bulk samples from a suspension of nanoparticles with a number of layers well in excess of 600, surpassing rival techniques by at least an order of magnitude. In addition to their large dimensions, the assembled metamaterials show a high degree of homogeneity and warrant an easy and rapid optical characterization using spectroscopic ellipsometry. We believe that the suggested inexpensive method considerably reduces the complexity in assembling optical metamaterials and opens new avenues in engineering bulk optical devices by choice of nanoparticle composition and geometry. ©2013 Optical Society of America OCIS codes: (160.0160) Materials; (160.3918) Metamaterials; (160.4236) Nanomaterials; (240.2130) Ellipsometry and polarimetry. References and links 1. C. M. Soukoulis and M. Wegener, “Past achievements and future challenges in the development of threedimensional photonic metamaterials,” Nat. Photonics 5, 523–530 (2011). 2. N. Liu, H. Guo, L. Fu, S. Kaiser, H. Schweizer, and H. Giessen, “Three-dimensional photonic metamaterials at optical frequencies,” Nat. Mater. 7(1), 31–37 (2008). 3. J. K. Gansel, M. Thiel, M. S. Rill, M. Decker, K. Bade, V. Saile, G. von Freymann, S. Linden, and M. Wegener, “Gold helix photonic metamaterial as broadband circular polarizer,” Science 325(5947), 1513–1515 (2009). 4. J. Valentine, S. Zhang, T. Zentgraf, E. Ulin-Avila, D. A. Genov, G. Bartal, and X. Zhang, “Three-dimensional optical metamaterial with a negative refractive index,” Nature 455(7211), 376–379 (2008). 5. T. Xu, A. Agrawal, M. Abashin, K. J. Chau, and H. J. Lezec, “All-angle negative refraction and active flat lensing of ultraviolet light,” Nature 497(7450), 470–474 (2013). 6. S. Mühlig, C. Rockstuhl, V. Yannopapas, T. Bürgi, N. Shalkevich, and F. Lederer, “Optical properties of a fabricated self-assembled bottom-up bulk metamaterial,” Opt. Express 19(10), 9607–9616 (2011). 7. L. Malassis, P. Massé, M. Tréguer-Delapierre, S. Mornet, P. Weisbecker, V. Kravets, A. Grigorenko, and P. Barois, “Bottom-up fabrication and optical characterization of dense films of meta-atoms made of core-shell plasmonic nanoparticles,” Langmuir 29(5), 1551–1561 (2013). 8. A. Merlin, J.-B. Salmon, and J. Leng, “Microfluidic-assisted growth of colloidal crystals,” Soft Matter 8(13), 3526–3537 (2012). 9. T. Nakamura, H. Fuji, N. Juni, and N. Tsutsumi, “Enhanced coupling of light from organic electroluminescent device using diffusive particle dispersed high refractive index resin substrate,” Opt. Rev. 13(2), 104–110 (2006). 10. D. W. Mosley, K. Auld, D. Conner, J. Gregory, X. Q. Liu, A. Pedicini, D. Thorsen, M. Wills, G. Khanarian, and E. S. Simon, “High-performance encapsulants for ultra high-brightness LEDs,” Proc. SPIE 6910, 691017, 691017-8 (2008). 11. K. C. Krogman, T. Druffel, and M. K. Sunkara, “Anti-reflective optical coatings incorporating nanoparticles,” Nanotechnology 16(7), S338–S343 (2005). 12. J. L. Regolini, D. Benoit, and P. Morin, “Passivation issues in active pixel CMOS image sensors,” Microelectron. Reliab. 47(4-5), 739–742 (2007). 13. P. Massé, S. Mornet, E. Duguet, M. Tréguer-Delapierre, S. Ravaine, A. Iazzolino, J.-B. Salmon, and J. Leng, “Synthesis of size-monodisperse spherical Ag@SiO2 nanoparticles and 3-D assembly assisted by microfluidics,” Langmuir 29(6), 1790–1795 (2013). #192887 $15.00 USD Received 25 Jun 2013; revised 9 Sep 2013; accepted 23 Sep 2013; published 1 Oct 2013 (C) 2013 OSA 1 November 2013 | Vol. 3, No. 11 | DOI:10.1364/OME.3.001792 | OPTICAL MATERIALS EXPRESS 1792 14. C. Fernández-López, C. Mateo-Mateo, R. A. Alvarez-Puebla, J. Pérez-Juste, I. Pastoriza-Santos, and L. M. LizMarzán, “Highly controlled silica coating of PEG-capped metal nanoparticles and preparation of SERS-encoded particles,” Langmuir 25(24), 13894–13899 (2009). 15. H. Fujiwara, Spectroscopic Ellipsometry: Principles and Applications, John Wiley and Sons Inc (2007). 16. G. E. Jellison and F. A. Modine, “Parametrization of the optical functions of amorphous materials in the interband region,” Appl. Phys. Lett. 69(3), 371–373 (1996). 17. J. Tauc, R. Grigorov, and A. Vancu, “Optical properties and electronic structures of amorphous germanium,” Phys. Status Solidi 15(2), 627–637 (1966).