Nonlinear dynamics of a single-gap terahertz split-ring resonator under electromagnetic radiation

Area of Science:

• Metasurfaces and nonlinear optics
• Terahertz (THz) technology
• Electromagnetic wave manipulation

Background:

• Metasurfaces are engineered materials controlling electromagnetic waves for applications in communications, cryptography, and sensing.
• Nonlinear metasurfaces offer undiscovered functionalities by manipulating electromagnetic fields.
• Understanding dynamic behaviors in nonlinear metasurfaces is crucial for advanced device development.

Purpose of the Study:

• To numerically investigate the dynamic behaviors of a nonlinear split-ring resonator (NSRR) under intense electromagnetic fields in the terahertz frequency range.
• To derive a mathematical model for examining NSRR excitation properties and identify tuning regions.
• To explore the potential of nonlinear metasurfaces for applications such as photonic memory devices.

Main Methods:

• Numerical investigation of charge carrier dynamics within an NSRR gap under intense electromagnetic fields.
• Derivation of a mathematical model to analyze NSRR excitation properties and parameter spaces.
• Analysis using bifurcation diagrams and dynamic region plots to study periodic, chaotic, and multistable behaviors.

Main Results:

• The NSRR exhibits periodic and chaotic dynamic patterns influenced by excitation field amplitude and loss parameters.
• Chaotic behavior diminishes with a very large loss parameter, with period doubling indicating transitions.
• Multistability, characterized by the coexistence of two stable states, was confirmed via basin of attraction analysis.

Conclusions:

• The study demonstrates complex dynamics, including chaos and multistability, in terahertz nonlinear split-ring resonators.
• The findings highlight the potential of nonlinear metasurfaces for developing novel photonic memory devices.
• Understanding these dynamic behaviors is a critical step towards realizing advanced THz applications.