Observation of distinct bound states in the continuum in the strained type-II Dirac photonic lattices

Abstract Bound states in the continuums (BICs) are localized states whose eigenvalues lie within the continuum spectrum of extended states. Here, we report the experimental observation of distinct BICs in the strained type-Ⅱ Dirac photonic lattices. Using direct femtosecond laser writing, we fabricate two such lattices with tailored geometries and boundary conditions, enabling the direct observation of corner states with unique phase profiles. These states remain embedded within—yet decoupled from—the bulk continuum, exhibiting strong localization analogous to BICs. Our work establishes a new platform for studying higher-order BICs in photonic systems and opens further opportunities in Dirac photonics.