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Bound states in the continuum can be defined as non-radiating resonant modes within open environments. These modes share a defining characteristic of being dark, displaying an exceptional degree of field localization. However, their practical accessibility lies in their quasi-bound form, which needs the introduction of perturbations in the system's geometry or material properties. Despite a finite, albeit high, quality factor, the quasi-bound modes manage to retain their characteristic strong field localization. In this presentation, our focus will be directed towards the exploration of symmetry-protected bound states in the continuum, delving into a comprehensive analysis of the impact that the introduction of various types of asymmetries can have on the formation and behavior of their quasi-bound counterparts. In particular, we will focus our attention on metasurfaces made of BaTiO3, whose constituent elements are periodically arranged nanowires. By investigating the topological features that contribute to certain mode selection rules, our analysis aims to provide a deeper understanding of the underlying mechanisms governing the formation and behavior of these modes. Our findings provide a strategic roadmap for optimizing the implementation of quasi-bound modes and provide a clear path to exploit them in specific applications such as sensing and nonlinear optical processes.
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