Ultra-slow-light and perfect light modulator based on quasi-BIC metasurface

Area of Science:

• Photonics and Metamaterials
• Optical Engineering

Background:

• Bound states in the continuum (BIC) offer unique light-matter interaction properties.
• Metasurfaces enable precise control over light propagation and polarization.
• Ultra-slow light generation is crucial for optical buffering and signal processing.

Purpose of the Study:

• To demonstrate an ultra-slow-light metasurface utilizing symmetrically protected bound states in the continuum (SP-BIC).
• To generate multiple electromagnetically induced transparency (EIT) windows with substantial group delays.
• To explore the metasurface's potential as a high-sensitivity sensor and polarization splitter.

Main Methods:

• Fabrication of a metasurface supporting multiple quasi-BIC (QBIC) resonances.
• Excitation of EIT windows through direct and indirect coupling mechanisms.
• Characterization of group delay, sensing sensitivity, and polarization splitting capabilities.

Main Results:

• Generation of three EIT windows using wavelength-stabilized QBICs.
• Achieved maximum group delays of 105 ps and 2771 ps, orders of magnitude higher than previous reports.
• Demonstrated a maximum sensing sensitivity of 415.5 nm/RIU.
• Exhibited perfect polarization splitting and filtering at 1550 nm for TM and TE light, respectively.

Conclusions:

• The developed SP-BIC metasurface enables ultra-slow light generation with unprecedented group delays.
• The metasurface shows great promise for high-sensitivity sensing applications.
• The polarization-selective properties allow for efficient polarization splitting and filtering across the optical communication spectrum.