Reversible Thermal Tuning of All‐Dielectric Metasurfaces

• Published in: Advanced functional materials Vol. 27; no. 31
• Main Authors: Rahmani, Mohsen, Xu, Lei, Miroshnichenko, Andrey E., Komar, Andrei, Camacho‐Morales, Rocio, Chen, Haitao, Zárate, Yair, Kruk, Sergey, Zhang, Guoquan, Neshev, Dragomir N., Kivshar, Yuri S.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 18.08.2017
• Subjects: all‐dielectric metasurfaces; Devices; Dielectrics; directionality; Electric communication systems; Lattice vibration; Magnetic dipoles; Magnetic resonance; Materials science; Metasurfaces; Mie resonance; Quadrupoles; Refractivity; Resonance scattering; reversible tuning; Scattering; Silicon; Tuning
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201700580

All‐dielectric metasurfaces provide a powerful platform for a new generation of flat optical devices, in particular, for applications in telecommunication systems, due to their low losses and high transparency in the infrared. However, active and reversible tuning of such metasurfaces remains a challenge. This study experimentally demonstrates and theoretically justifies a novel scenario of the dynamical reversible tuning of all‐dielectric metasurfaces based on the temperature‐dependent change of the refractive index of silicon. How to design an all‐dielectric metasurface with sharp resonances by achieving interference between magnetic dipole and electric quadrupole modes of constituted nanoparticles arranged in a 2D lattice is shown. Thermal tuning of these resonances can cause drastic but reciprocal changes in the directional scattering of the metasurface in a spectral window of 75 nm. This change can result in a 50‐fold enhancement of the radiation directionality. This type of reversible tuning can play a significant role in novel flat optical devices including the metalenses and metaholograms. Via controlling the temperature and employing the right combination of the electric and magnetic resonant responses of the metasurfaces, drastic and reciprocal interchanges in directional scattering are demonstrated experimentally and theoretically. At 1425 nm forward to backward ratio variation from 1 to >50 can be obtained. The results provide an important step toward tunable nanophotonic components and all‐optical circuitry on a chip.