Rabi oscillation dynamics and Mollow splitting in cylindrical quantum dots under external fields

Abstract

Semiconductor quantum dots represent versatile nanoscale systems whose electronic and optical properties can be precisely tuned through their geometry and external perturbations. This paper presents a theoretical investigation of the electronic dynamics in a two-level system confined within a cylindrical GaAs quantum dot embedded in a Ga₁₋ₓAlₓAs matrix. A modified Pöschl–Teller potential model is used to describe the axial confinement, while a parabolic potential is employed to describe the radial confinement. The study focuses on the influence of an external electric field and geometrical parameters on the Rabi oscillation behavior and the resulting Mollow spectrum. The results demonstrate that increasing the electric field intensity enhances the amplitude of Rabi oscillations up to a threshold (F ≈ 2.8 ×10⁵ V/cm), after which amplitude intermixing and saturation occur. Beyond a critical field (F ≈ 1.2 ×10⁶ V/cm), a reappearance of oscillatory gaps is observed, indicating field-induced redistribution between the ground and excited states. Variation of the QD half-width (3–7 nm) affects the oscillation frequency but not its amplitude, underscoring the role of confinement geometry in coherent carrier dynamics. The calculated Mollow spectrum exhibits symmetric sideband splitting with increasing Rabi frequency, maintaining resonance with the laser field and revealing dephasing-induced linewidth broadening. These results provide insight into the coherent control of charge-carrier dynamics in semiconductor quantum dots, contributing to the design of tunable quantum optoelectronic devices.