Recently, Associate Professor Xu Zhengji's research team from the School of Microelectronics Science and Technology at Sun Yat-sen University made a splash in the academic world. Their research, titled "Angle-Independent Universal Polarization and Angle-Insensitive Quasi-Bound States in the Continuum Enabled by Metasurface Degeneracy Protection," was published in the esteemed international optics journal, Laser & Photonics Reviews. This groundbreaking study was primarily driven by Zhang Shubin, a doctoral graduate from the Class of 2025, who took the lead as the first author. Associate Professor Xu Zhengji was the sole corresponding author, providing invaluable guidance throughout the research process.

The research presents a pioneering method that leverages metasurface degeneracy protection to achieve polarization and angle insensitivity in bound states in the continuum (BIC). This innovative approach involves the strategic manipulation of geometric asymmetry, enabling precise control over the Q-factor of the BIC modes. To validate the stability of these modes under diverse polarizations and incident angles, the team employed the Finite-Difference Time-Domain (FDTD) method, a widely recognized computational technique in the field of electromagnetics.

Furthermore, the team successfully fabricated the designed photonic crystal and conducted rigorous experimental verification. Through FTIR spectroscopy measurements, they confirmed the angle insensitivity of the photonic crystal, observing consistent wavelengths across various angles. The slight broadening of linewidths observed was attributed to manufacturing tolerances, a common challenge in experimental physics.

This remarkable achievement opens up a wealth of possibilities for applications in biomedical diagnostics, optical sensing, and beyond. Its potential to revolutionize these fields underscores the significance of this research, positioning it as a cornerstone for future advancements in optics and photonics.