Analog of multiple electromagnetically induced transparency using double-layered metasurfaces.

Area of Science:

• Metamaterials
• Plasmonics
• Electromagnetics

Background:

• Electromagnetically induced transparency (EIT) is a quantum interference effect enabling optical properties like high-Q resonances.
• Metasurfaces offer a platform to mimic EIT phenomena in classical regimes, known as analog EIT (A-EIT).
• Achieving multiple A-EIT peaks typically requires complex designs and coupling mechanisms.

Purpose of the Study:

• To realize and investigate an analog of electromagnetically induced transparency (A-EIT) exhibiting double transparent peaks.
• To explore the potential of a hybrid double-layered metasurface for generating multiple A-EIT.
• To provide theoretical and experimental validation for the observed double-peaks A-EIT phenomenon.

Main Methods:

• Fabrication of a double-layered metasurface comprising spoof localized surface plasmons (S-LSP) and cut-wire (CW)-square rings (SR) hybrid.
• Excitation of electric and magnetic S-LSP modes as bright and dark modes, respectively.
• Coupling of S-LSP modes with resonant modes of CW and SR to achieve multiple A-EIT.

Main Results:

• Demonstration of a double-peaks A-EIT spectrum through the hybrid metasurface.
• Observation of a bright-bright mode A-EIT arising from the coupling of electric S-LSP and SR bright modes.
• Observation of a bright-dark mode A-EIT induced by near-field coupling of magnetic S-LSP (dark mode) with CW.

Conclusions:

• The designed double-layered metasurface successfully achieves multiple A-EIT with distinct spectral features.
• The hybrid structure enables simultaneous excitation and coupling of multiple resonant modes, leading to the double-peaks phenomenon.
• Theoretical analysis and microwave experiments confirm the physical mechanism behind the observed double-peaks A-EIT.