Additional modes in a waveguide system of zero-index-metamaterials with defects

Area of Science:

• Metamaterials and Nanophotonics
• Wave Physics
• Electromagnetism

Background:

• Zero-index metamaterials (ZIM) exhibit unique wave manipulation properties.
• ZIM waveguides with defects allow for total reflection or transmission.
• Previous studies predominantly identified monopole modes in cylindrical defects.

Purpose of the Study:

• To challenge the common perception of mode excitation in ZIM defects.
• To theoretically and numerically investigate the excitation of additional modes in ZIM defects.
• To explore mode behavior in both matched impedance ZIM (MIZIM) and epsilon-near-zero (ENZ) metamaterials.

Main Methods:

• Theoretical analysis of wave propagation in ZIM waveguide defects.
• Numerical simulations to verify predicted mode behavior.
• Investigation of matched impedance ZIM (MIZIM) and epsilon-near-zero (ENZ) materials.

Main Results:

• Additional dipole modes are excited in MIZIM defects during total transmission.
• Higher-order modes, such as tri-pole modes, are observed in ENZ defects during total transmission.
• Findings are consistent in both theoretical MIZIM and Dirac-cone-like photonic crystals.

Conclusions:

• The excitation of additional modes in ZIM defects is a critical, previously overlooked phenomenon.
• This discovery corrects the prevailing understanding of wave behavior in ZIM systems.
• The findings have implications for designing advanced ZIM-based devices and applications.