Electrical Tuning of Optical Stark Effect in Monolayer WS₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• The optical Stark effect (OSE) involves photon-dressed states and band renormalization under strong light.
• Previous OSE research focused on optical control of fluence, detuning, and polarization.

Purpose of the Study:

• To demonstrate electrical tuning of valley-selective OSE in monolayer WS2.
• To investigate the underlying mechanisms of electrically controlled OSE.

Main Methods:

• Utilized a back-gated monolayer WS2 device.
• Employed helicity-resolved transient absorption spectroscopy (TAS).

Main Results:

• Successfully achieved electrical tuning of valley-selective OSE.
• Observed enhanced transition dipole moment and exciton oscillator strength under electrical control.
• Noted deviations in OSE blue shift at high negative voltages, suggesting complex origins beyond steady-state exciton density.

Conclusions:

• Electrical tuning provides a new control parameter for Floquet engineering in 2D materials.
• The findings offer deeper insights into light-matter interactions in 2D systems.
• Highlights the potential for electrical manipulation of quantum phenomena in transition metal dichalcogenides.