High-Quality-Factor EH Modes in Microcylinder Resonators Predicted by 3D FDTD Simulation

The mode characteristics of a microcylinders with center layer thickness 0.2 mum and radius 1 mum are investigated by the three-dimensional (3D) finite-difference time-domain (FDTD) technique and the Pade approximation. The mode quality factor (Q-factor) of the EH
₇₁
mode obtained by 3D FDTD increase with the increase of the refractive index of the cladding layer n
₂
as n
₂
smaller than 3.17, and can be as large as 2.4 times 10
⁴
as the vertical refractive index distribution is 3.17/3.4/3.17, which is much larger than that of the HE
₇₁
mode with the same vertical refractive index distribution.