Tunable phonon-induced transparency in bilayer graphene nanoribbons

Area of Science:

• Condensed matter physics
• Optics
• Materials science

Background:

• Plasmon-induced transparency (PIT) is a phenomenon analogous to electromagnetically induced transparency (EIT) in atomic systems.
• It arises from coherent interference between two plasmon modes, creating a transparency window within an absorption spectrum.
• Typically, one plasmon mode acts as a 'dark mode' with a longer lifetime and limited radiation coupling.

Purpose of the Study:

• To investigate an analogous phenomenon, phonon-induced transparency (PIT), in AB-stacked bilayer graphene nanoribbons.
• To explore the tunability of PIT via electrostatic gating.
• To demonstrate potential applications in slow light and nonlinear optics.

Main Methods:

• Experimental observation of PIT in bilayer graphene nanoribbons.
• Utilizing the coupling between plasmon excitation and infrared active Γ-point optical phonons.
• Employing electrostatic gating for active tunability.

Main Results:

• Demonstration of PIT in AB-stacked bilayer graphene nanoribbons, suppressing light absorption in a narrow window.
• Active tunability of PIT by electrostatic gating.
• Estimation of a maximum slow light factor of approximately 500 at 1580 cm⁻¹.

Conclusions:

• Phonon-induced transparency is achieved in bilayer graphene, analogous to plasmon-induced transparency.
• The phenomenon is actively tunable, offering control over optical properties.
• This work opens avenues for exploring few-photon nonlinear optics and slow light in two-dimensional materials.