Tunable plasmonic filter based on parallel bulk Dirac semimetals at terahertz frequencies

Area of Science:

• Nanophotonics and Plasmonics
• Condensed Matter Physics
• Materials Science

Background:

• Plasmonic filters are crucial for manipulating light at the nanoscale.
• Bulk Dirac semimetals (BDSs) offer unique electronic and optical properties for device applications.

Purpose of the Study:

• To propose and numerically investigate a novel plasmonic bandpass filter.
• To explore the tunability of filter performance through various parameters.
• To simulate a plasmonic broadband filter using coupling mode splitting.

Main Methods:

• Finite-difference time-domain (FDTD) method for numerical simulations.
• Analysis based on evanescent coupling and Fabry-Perot resonant theory.
• Simulation of coupling mode splitting for broadband filtering.

Main Results:

• Demonstration of a tunable plasmonic bandpass filter based on parallel BDSs.
• Identification of key parameters for performance tuning: coupling distance, resonator length, and Fermi levels.
• Successful simulation of a plasmonic broadband filter by arranging two resonators.

Conclusions:

• The proposed BDS-based plasmonic filter offers tunable performance for optical applications.
• Evanescent coupling and Fabry-Perot resonance are key to the filter's mechanism.
• The study presents a viable approach for designing advanced plasmonic filters.