Plasmonic-induced absorption in an end-coupled metal-insulator-metal resonator structure

An end-coupled composite-slot-cavity resonator (CSCR) is proposed based on the subwavelength metal-insulator-metal (MIM) waveguides. When compared with the perfect slot cavity, which acts as a Fabry–Perot resonator, plasmonic-induced absorption effect is achieved in the CSCR system. Single or dual absorption windows will arise at the former transmission peaks by arranging the position of vertical-slot cavity in the CSCR. According to the analyses on the phase responses, abnormal dispersions will be achieved inside the windows. Therefore, one can manipulate the fast-light applications in the nano-scale integrated circuits. Furthermore, based on the same interference effect, plasmonic-induced transparency response with normal dispersion is also obtained by changing the end-coupled CSCR system to a side-coupled one. The performances of the proposed structure are analyzed and investigated using the coupled mode theory and the finite-difference time-domain method, respectively.