In this paper, the resonance expansion of quadratic quantities is resented and applied to a circular Bragg grating resonator. Therefore the Riesz Projection method is applied and the electromagnetic field is described via quasinormal modes, the fields and quantities are computed with JCMsuite.
F. Betz, et al. Resonance Expansion of Quadratic Quantities with Regularized Quasinormal Modes. Physica status solidi (a), 220, 2200892 (2023).