75 research outputs found
Calculation, normalization and perturbation of quasinormal modes in coupled cavity-waveguide systems
We show how one can use a non-local boundary condition, which is compatible
with standard frequency domain methods, for numerical calculation of
quasinormal modes in optical cavities coupled to waveguides. In addition, we
extend the definition of the quasinormal mode norm by use of the theory of
divergent series to provide a framework for modeling of optical phenomena in
such coupled cavity-waveguide systems. As an example, we apply the framework to
study perturbative changes in the resonance frequency and Q value of a photonic
crystal cavity coupled to a defect waveguide.Comment: 4 pages, 3 figure
Effective mode volumes and Purcell factors for leaky optical cavities
We show that for optical cavities with any finite dissipation, the term
"cavity mode" should be understood as a solution to the Helmholtz equation with
outgoing wave boundary conditions. This choice of boundary condition renders
the problem non-Hermitian, and we demonstrate that the common definition of an
effective mode volume is ambiguous and not applicable. Instead, we propose an
alternative effective mode volume which can be easily evaluated based on the
mode calculation methods typically applied in the literature. This corrected
mode volume is directly applicable to a much wider range of physical systems,
allowing one to compute the Purcell effect and other interesting optical
phenomena in a rigorous and unambiguous way
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