A synergistic approach to optical modeling of PCSELs through rigorous methods and the coupled-wave theory

A wide range of numerical and semi-analytical approaches has been developed for optical modeling of photonic-crystal surface-emitting lasers (PCSELs). However, a systematic framework for comparing their predictive capabilities and identifying their respective validity limits remains largely unexplored. In this work, we introduce a comparative methodology in which four representative methods-including rigorous numerical and effective-index-based approaches-are analyzed and partially hybridized within a coupled-wave-theory framework. Using single- and double-lattice PCSELs as representative models, we demonstrate that this approach not only reveals fundamental differences between predictions of rigorous methods and the coupled-wave-theory framework, but also captures leaky and symmetry-broken phases of bound states in the continuum (BICs) relevant for laser operation.