Abstract
Nature has long inspired scientists and engineers to develop transparent surfaces via constructing anti-reflective surfaces. In absence of anti-reflection (AR) coating, silicon reflects about 35% of light for a single interface air−silicon. Here, inspired by jellyfish anti-reflective eyes, a man-made anti-reflective surface on the facet of the waveguide is proposed and demonstrated for waveguides transparency in near-infrared. The optimized metamaterial with unit cells of 560 × 560 nm shows transparency of 2.6 times better as compared to the waveguide with blank facet. Metasurfaces are milled on the waveguides facets with a focused ion beam. Silicon-on-insulator waveguides are tested with an inline set-up. Far-field scattering diagrams reveal that it is the special geometry of the unit cells of the engraved metamaterial, which can be associated with the directional scattering resulting in combined effect: on one hand the ultra-high transparency of the device and on the other hand the efficient coupling to the low-order modes due to the focusing dielectric nano-antennas effect. Reported here waveguide facets as AR metamaterials on a chip, opens up opportunities to engineer transparent on-chip devices with high coupling efficiency for diverse applications from sensing to quantum technologies.
Original language | English |
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Article number | 2100130 |
Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Advanced Optical Materials |
Volume | 9 |
Issue number | 11 |
Early online date | 24 Apr 2021 |
DOIs | |
State | Published - 4 Jun 2021 |
Keywords
- anti-reflection vertical bar anti-reflective metasurfaces
- all-dielectric nanophotonics
- gradient index
- integrated photonics
- silicon waveguides
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics