Plasmons induced by topological insulator (TI) Bi<sub>2</sub>Se<sub>3</sub> micro-ribbon arrays have been experimentally observed recently
(<strong><i>Nature nanotechnology</i> 2013, 8, 556-560</strong>). In this letter, the surface plasmons excited by TI Bi<sub>2</sub>Se<sub>3</sub> micro-disk arrays
are investigated by the methods of full-wave numerical simulations. Numerical simulation results show that thin Bi<sub>2</sub>Se<sub>3</sub>
micro-disk arrays can support dipolar plasmon resonances in the terahertz (THz) regimes and the absorptions can be
tuned by the structure parameters. In addition to the plasmon mode, two phonon-mode responses are also observed,
which confirms the experimental results of micro-ribbon arrays. Our work further proves that TI can be a good candidate
of plasmonic platform.