2024-03-29T09:41:45Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1682842021-10-27T11:24:59Zcom_10261_93com_10261_4col_10261_472
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Toudert, Johann
author
Serna, RosalĂa
author
2017-11-27
During the last years, the fields of plasmonics and nanophotonics have been strengthened by the identification of alternative plasmonic materials better suited than gold and silver for specific applications, and by the demonstration of low-loss Mie resonances in subwavelength dielectric nanostructures. These findings have stimulated the development of a rich variety of new material architectures, appealing for plasmonic applications at high temperatures and beyond the visible, and for low-loss nanophotonics.
Currently, in the fields of plasmonics and nanophotonics two main challenges concerning the material platforms can be identifie: first the need to achieve materials with a reversibly tunable dielectric function for the development of switchable plasmonic devices, and second the need to achieve dielectrics with a very high refractive index in order to enable low-loss nanophotonics compete with plasmonics in terms of miniaturization. For the first case plasmonic materials, where the driving mechanism is the excitation of free charge carriers, are not reversibly tunable. For the second case, Silicon, the most used platform for low-loss Mie resonances, has a refractive index of 4 that sets the minimum size of visible-near infrared resonators at more than 100 nm.
However there is a kind of materials that can address both challenges. Recently, there have been demonstrations of ultraviolet-visible plasmon resonances without need of free charge carrier excitation in semi-metals and topological insulators,1,2 and of low-loss Mie resonances in subwavelength nanostructures of lead telluride, semiconductor with a refractive index of 6.3 We will demonstrate that the optical properties of these materials, which all consist of elements of the p-block of the periodic table, are driven by giant interband transitions. These interband transitions make the material behave optically as a metal (negative dielectric permittivity) at their high energy side, and as a high refractive index dielectric at their low energy side. The magnitudes of the negative permittivity and high refractive index depend on the strength of the interband transitions. In this context, we will evaluate the potential of a broad range of elements and compounds of the p-block for plasmonics and low-loss nanophotonics.4 We will make a special emphasis on bismuth that presents the strongest interband transitions reported so far,5 which enable its plasmonic behavior in the ultraviolet-visible and yield an infrared refractive index close to 10. Finally, we will report the tunability of its dielectric function in relation with plasmonics and nanophotonics both in the ultraviolet-visible and infrared regions.
1. J. Yin, H. N. S. Krishnamoorthy, G. Adamo, et al., arXiv:1702.00302 [ physics.optics]
2. J. Toudert, and R. Serna, Opt. Mat. Expr. 7, 2434 (2016).
3. T. Lewi, H. A. Evans, N. A. Butakov, J. A. Schuller, NanoLett. 17, 3940 (2017).
4. J. Toudert, and R. Serna, Opt. Mater. Express 7, 2299 (2017).
5. J. Toudert, R. Serna, I. Camps, J. Wojcik, P. Mascher, E. Rebollar, T. Ezquerra, J. Phys. Chem. C 121, 3511 ( 2017).
MRS Fall Meeting & Exhibit (2017)
http://hdl.handle.net/10261/168284
Giant interband transitions: Towards switchable plasmonics and low-loss nanophotonics on a single-material platform