Quality Factor Computation in Time Domain for Cylindrical Optical Cavities

We investigate the computation of resonance frequencies and quality factors in an optical cylindrical cavity with a curved upper distributed Bragg reflector (DBR). Both values of interest shall be extracted from FDTD-like time domain simulations with an absorbing boundary condition (ABC). The quality factor solely originates from the light emission through the mirror (neglecting material losses) and hence strongly depends on the performance of the discretization and the ABC. Additionally, the fields in the cavity are slowly decaying and the structure of the DBR may lead to long setting times. Finally, we show, that both values converge w.r.t. the mesh resolution.