Topologically enhanced harmonic generation in a nonlinear transmission line metamaterial

Area of Science:

• Nonlinear electronics
• Condensed matter physics
• Topological photonics

Background:

• Nonlinear transmission lines (NLTLs) are crucial for parametric amplification and pulse generation.
• Left-handed NLTLs enhance harmonic generation and suppress shock waves.
• Nonlinear Su-Schrieffer-Heeger (SSH) circuits have been studied for solitonic behaviors.

Purpose of the Study:

• To experimentally investigate harmonic generation in a left-handed NLTL analogue of the SSH lattice.
• To demonstrate the role of topological edge states in enhancing harmonic generation.
• To explore potential applications in compact electronic frequency generators.

Main Methods:

• Experimental realization of a left-handed NLTL SSH lattice analogue.
• Measurement of harmonic signal intensities.
• Comparison of topological and trivial configurations.

Main Results:

• A topological edge state at the first harmonic greatly increases harmonic generation.
• Maximum third-harmonic signal intensities were five times higher than conventional NLTLs.
• A 250-fold intensity contrast was observed between topologically nontrivial and trivial configurations.

Conclusions:

• Topological edge states act as nonlocal cross-phase nonlinearities, enhancing higher-harmonic generation.
• This work advances the understanding of nonlinear topological states.
• Potential applications exist for compact electronic frequency generators.