(a) 2D color map of reflectivity as a function of frequency and incident angle. Pink and red circles indicate the positions of SP-BIC, and purple points represent SPPs. (b) Q factors of QBIC as a function of incident angle for the hybrid structure (green) and the plasmonic structure (red). (c) Electric field distribution of the BIC in the x-z plane under the TE₁ mode in the hybrid THz-MS. (d) Electric field distribution of the BIC in the x-z plane under the TE₂ mode in the hybrid THz-MS.