Premium
Active Control of Nanodielectric‐Induced THz Quasi‐BIC in Flexible Metasurfaces: A Platform for Modulation and Sensing
Author(s) -
Tan Thomas CaiWei,
Srivastava Yogesh Kumar,
Ako Rajour Tanyi,
Wang Wenhao,
Bhaskaran Madhu,
Sriram Sharath,
AlNaib Ibraheem,
Plum Eric,
Singh Ranjan
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202100836
Subject(s) - metamaterial , terahertz radiation , materials science , optoelectronics , resonator , photoexcitation , nanophotonics , ultrashort pulse , dielectric , modulation (music) , fano resonance , optics , plasmon , physics , excitation , laser , quantum mechanics , acoustics
A bound state in the continuum (BIC) is a nonradiating state of light embedded in the continuum of propagating modes providing drastic enhancement of the electromagnetic field and its localization at micro–nanoscale. However, access to such modes in the far‐field requires symmetry breaking. Here, it is demonstrated that a nanometric dielectric or semiconductor layer, 1000 times thinner than the resonant wavelength (λ/1000), induces a dynamically controllable quasi‐bound state in the continuum (QBIC) with ultrahigh quality factor in a symmetric metallic metasurface at terahertz frequencies. Photoexcitation of nanostrips of germanium activates ultrafast switching of a QBIC resonance with 200% transmission intensity modulation and complete recovery within 7 ps on a low‐loss flexible substrate. The nanostrips also form microchannels that provide an opportunity for BIC‐based refractive index sensing. An optimization model is presented for (switchable) QBIC resonances of metamaterial arrays of planar symmetric resonators modified with any (active) dielectric for inverse metamaterial design that can serve as an enabling platform for active micro–nanophotonic devices.