Recently, a collaborative research team led by Liang Wu and Jianquan Yao from Tianjin University, in partnership with the Aerospace Information Research Institute of the Chinese Academy of Sciences and the Southern University of Science and Technology, has made a significant breakthrough. Their findings, published in the prestigious international journal National Science Review, introduce an innovative double-layer terahertz metasurface design rooted in S4 point group symmetry. This groundbreaking architecture enables the realization of symmetry-protected quasi-bound states in the continuum (QBIC), exhibiting remarkable resilience against structural defects and manufacturing inaccuracies. This advancement overcomes the inherent fragility of traditional QBIC systems, which are notoriously susceptible to even minor structural variations, thereby opening up new avenues for the mass production of high-performance terahertz photonic devices.