Q factors and resonant states of whispering-gallery-mode dielectric microdisk cavities for lasing applications

The effect of boundary roughness on the resonant states broadening of the optical whispering-gallery-mode microdisk lasing cavities is studied. A new, computationally effective, and numerically stable approach based on the scattering matrix (S-matrix) technique that is capable to deal with both arbitrary complex geometry and inhomogeneous refraction index inside the two-dimensional cavity is developed. In order to calculate the lifetime of the cavity modes (and, therefore their Q-factors) the Wigner-Smith time delay-matrix is computed which, in turn, is expressed in terms of the total scattering matrix. The developed algorithm to the calculation of resonant states and Q-values of nonideal microdisk cavities is applied.