Presentation Information
[8a-E218-4]Avoided Crossing between Fabry–Pérot Modes and quasi-BIC Plasmonic Modes in a Babinet Complementary Metal Mesh Structure
Shuhei Matsuyama1, 〇(B)Miyuu Matsunaga1, Yasuyuki Sakanaka1, Yoshinori Shohmitsu2, Takehiko Wada3, Toyoaki Suzuki4, Toshihiro Nakaoka1 (1.Sophia Univ., 2.QUP/KEK, 3.NAOJ, 4.ISAS/JAXA)
Keywords:
Terahertz,Optical Filter,Fano Resonance
We analyzed the Fabry–Pérot (FP) mode and a plasmonic mode that forms a symmetry-protected bound state in the continuum (BIC) at the Γ point in a THz-band band-pass filter consisting of a deep-etched silicon structure and Babinet-complementary metal meshes using a two-pole complex Lorentz model. The analysis revealed that the plasmonic mode transitions from a symmetry-protected BIC to a quasi-BIC under oblique incidence and exhibits an avoided crossing with the FP mode. The FTIR reflectance spectra were well reproduced by the model, revealing that the losses of the two modes approach each other near the avoided crossing owing to mode hybridization.