Experimental Evidence of THz-LSPR in Microstructures Patterned Bi2Se3 Topological Insulator Thin Films

Terahertz band, which corresponds to the energy of inter-molecular binding, is expected to enable us a non-labeling detection such as antigen-antibody binding. We aim to enhance the sensitivity by surface plasmon resonance (SPR) combined with the signal enhancement effect due to the selective resonant excitation of the specific binding. In this study, we have focused on the topological insulators. They enhance SPR in THz band and confirm the occurrence of localized surface plasmon resonance by using periodic microstructures of well crystallized and prefer oriented Bi
₂
Se
₃
thin films fabricated by a pulsed laser deposition. We also observed the avidin-biotin coupling by THz-SPR, which is the first experimental observation of biological material interactions through THz-SPR using topological insulator.