Electrostatic Control of Nonlinear Photonic-Crystal Polaritons in a Monolayer Semiconductor

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanophotonics

Background:

• Strong light-matter coupling is essential for developing advanced optical devices.
• Two-dimensional (2D) semiconductors integrated with photonic crystal slabs offer a promising platform for chip-compatible polaritonics.
• Tunability and nonlinear optical response are critical for practical polaritonic device applications.

Purpose of the Study:

• To investigate tunable exciton-polaritons in a gated photonic crystal slab with monolayer Molybdenum Diselenide (MoSe₂).
• To demonstrate a novel optical control method based on polariton nonlinearity.
• To explore the potential for active polaritonic devices in compact implementations.

Main Methods:

• Fabrication of an electrostatically gated photonic crystal slab incorporating monolayer MoSe₂.
• Experimental study of neutral and charged exciton-polaritons under optical pumping.
• Analysis of nonlinear optical responses and electrostatic tuning effects.

Main Results:

• Spatial modulation of the dielectric environment created two distinct excitonic species.
• These species exhibited significantly different nonlinear responses in charged exciton-polaritons.
• Optical switching was achieved using ultrashort laser pulses and controlled via gate voltage.

Conclusions:

• The study presents a novel approach for optical control of exciton-polaritons based on their nonlinear properties.
• The demonstrated tunability via electrostatic gating is crucial for active polaritonic devices.
• These findings pave the way for compact, chip-compatible active polaritonic devices.