Magnetoplasmonics Lab

Archives December 17, 2023

Our new paper on THz

Our new َArticle in Journal of nature

Design and analysis of a fexible Ruddlesden–Popper 2D perovskite metastructure based on symmetry‑protected THz‑bound states in the continuum

Seyedeh Bita Saadatmand, Samad Shokouhi, VahidAhmadi & Seyedeh Mehri Hamidi

A Ruddlesden–Popper 2D perovskite PEA2PbX4 (X= I, Br, and Cl) is proposed for metasurface applications. Density functional theory is used to analyze the optical, electrical, mechanical properties, moisture and thermodynamic stability of PEA2PbX4. The refractive index of PEA2PbX4 varies with the halides, resulting in 2.131, 1.901, and 1.842 for X= I, Br, and Cl, respectively. Mechanical properties with Voigt-Reuss-Hill approximations indicate that all three materials are fexible and ductile. Based on the calculations of formation energy and adsorption of water molecules, PEA2PbI4 has superior thermodynamic and moisture stability. We present a novel metasurface based on 2D-PEA2PbI4 and analyze symmetry protected-bound states in the continuum (sp-BIC) excitation. The proposed structure can excite multiple Fano quasi-BICs (q-BICs) with exceptionally high Q-factors. We verify the group theoretical analysis and explore the near-feld distribution and far-field scattering of q-BICs. The findings indicate that x-polarized incident waves can excite magnetic toroidal dipole electromagnetic-induced transparency-BIC and magnetic quadrupole-BIC, while y-polarized incident waves can excite electric toroidal dipole-BIC and electric quadrupole-BIC. The influence of metaatom and substrate losses, array size limitations, and fabrication tolerances are also discussed. The proposed structure can be employed for applications in the THz region, such as polarization dependent filters, bidirectional optical switches, and wearable photonic devices.