Mode Simulation for Midinfrared Microsquare Resonators With Sloped Sidewalls and Confined Metals

Mode characteristics for midinfrared microsquare resonators with sloped sidewalls and confined metal layers are investigated by finite-difference time-domain (FDTD) techniques. For a microsquare with a side length of 10 ¿m, the mode quality (
Q
) -factors of 8329, 4772, and 2053 are obtained for TM
_5,7
mode at wavelength 7.1 ¿m by three-dimensional FDTD simulations, as the tilting angles of the side walls are 90°, 88°, and 86°, respectively. Furthermore, microsquare resonators laterally surrounded by SiO
₂
and metal layers are investigated by the two-dimensional FDTD technique for the metal layers of Au, Ti-Au, Ag-Au, and Ti-Ag-Au, respectively.