Resonator-free optical bistability based on epsilon-near-zero mode

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nonlinear Optics

Background:

• Existing optical bistability research predominantly uses resonant schemes with nonlinear materials.
• Resonant schemes necessitate a trade-off between switching intensity and response time, limiting device performance.

Purpose of the Study:

• To propose and demonstrate a novel non-resonant scheme for optical bistability.
• To overcome the inherent trade-off limitations of resonance-based optical bistability.
• To design an integrated optical device for efficient optical bistability.

Main Methods:

• Utilizing the strong light enhancement of the epsilon-near-zero (ENZ) mode.
• Employing graphene as a nonlinear ENZ material.
• Designing an integrated optical device with a graphene-embedded silicon (Si) waveguide supporting an ENZ mode.

Main Results:

• Demonstrated optical bistability via a non-resonant scheme.
• Achieved a significantly short response time of approximately 200 femtoseconds (fs).
• Attained a low switching intensity of around 700 kW/cm².

Conclusions:

• The proposed non-resonant scheme effectively overcomes the switching intensity-response time trade-off in optical bistability.
• The graphene-embedded Si waveguide device offers simultaneous low switching intensity and fast response times.
• This work presents a promising pathway for advanced optical switching devices.