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arXiv · 1511.09428

Photoinduced tunability of the Reststrahlen band in 4H-SiC

Bryan T. Spann·Ryan Compton·Daniel Ratchford·James P. Long·Adam D. Dunkelberger·Paul B. Klein·Alexander J. Giles·Joshua D. Caldwell·Jeffrey C. Owrutsky
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Abstract

Materials with a negative dielectric permittivity (e.g. metals) display high reflectance and can be shaped into nanoscale optical-resonators exhibiting extreme mode confinement, a central theme of nanophotonics. However, the ability to $actively$ tune these effects remains elusive. By photoexciting free carriers in 4H-SiC, we induce dramatic changes in reflectance near the "Reststrahlen band" where the permittivity is negative due to charge oscillations of the polar optical phonons in the mid-infrared. We infer carrier-induced changes in the permittivity required for useful tunability (~ 40 cm$^{-1}$) in nanoscale resonators, providing a direct avenue towards the realization of actively tunable nanophotonic devices in the mid-infrared to terahertz spectral range.

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Bryan T. Spann, Ryan Compton, Daniel Ratchford, James P. Long, Adam D. Dunkelberger, Paul B. Klein, Alexander J. Giles, Joshua D. Caldwell, Jeffrey C. Owrutsky. 2015-11-30. Photoinduced tunability of the Reststrahlen band in 4H-SiC. https://doi.org/10.1103/physrevb.93.085205

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