2026-05-30T07:01:23Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/166952026-02-03T10:48:38Zcom_10630_2254col_10630_37953

Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides Luque-González, José Manuel Herrero-Bermello, Alaine Ortega-Moñux, Alejandro Molina-Fernández, Íñigo Halir, Robert Wang, Shurui Schmid, Jens H. Cheben, Pavel Velasco, Aitor V. Optica integrada Subwavelength grating (SWG) structures are an essential tool in silicon photonics, enabling the synthesis of metamaterials with a controllable refractive index. Here we propose, for the first time to the best of our knowledge, tilting the grating elements to gain control over the anisotropy of the metamaterial. Rigorous finite difference time domain simulations demonstrate that a 45° tilt results in an effective index variation on the fundamental TE mode of 0.23 refractive index units, whereas the change in the TM mode is 20 times smaller. Our simulation predictions are corroborated by experimental results. We furthermore propose an accurate theoretical model for designing tilted SWG structures based on rotated uniaxial crystals that is functional over a wide wavelength range and for both the fundamental and higher order modes. The proposed control over anisotropy opens promising venues in polarization management devices and transformation optics in silicon photonics. 2018-10-24T09:42:36Z 2018-10-24T09:42:36Z 2018-10-24 journal article https://hdl.handle.net/10630/16695 https://doi.org/10.1364/OL.43.004691 eng open access