Rabi Oscillations in WSe₂ Monolayers Enable Controlled Exciton Population Transfer for Quantum Photonic Devices

Rabi oscillations, the fundamental basis of controlling quantum states, are now being observed in atomically thin materials, opening new avenues for advanced quantum technologies. Victor N. Mitryakhin, Ivan A. Solovev, and colleagues at the Institute of Physics, Carl von Ossietzky University of Oldenburg, and others, demonstrate these oscillations within a single layer of tungsten diselenide. The team drives the material with precise laser pulses, inducing a transfer of energy between quantum states and observing the resulting rhythmic changes in light emission. This research establishes a pathway towards coherently controlling light-emitting materials at the nanoscale, a critical step in developing high-performance single photon sources for applications in quantum communication and computing.

Strongly Driven Rabi Oscillations in Monolayers

Rabi oscillations, a fundamental phenomenon in quantum optics, emerge when a quantum two-level system interacts with a resonant driving field. This work investigates Rabi oscillations within a monolayer of quantum emitters, demonstrating coherent control over these oscillations with 99% fidelity in state manipulation and observing transitions to higher energy levels. The team employed time-resolved photoluminescence spectroscopy to map the energy landscape and track the population dynamics of the quantum emitter with unprecedented precision, revealing a complex interplay between the driving field, the emitter’s energy levels, and quantum coherence. These findings establish a pathway towards advanced quantum technologies, including efficient single-photon sources and coherent quantum memories, by harnessing the unique properties of monolayer quantum emitters.

Strain-Induced Quantum Dots in WSe2 Monolayer

This study investigates coherent control of excitons within a monolayer of tungsten diselenide (WSe2), a material with strong potential for advanced photonic devices. Researchers engineered a system to manipulate the quantum state of excitons within nanoscale quantum dots formed in the WSe2 monolayer through mechanical exfoliation and transfer onto a complex heterostructure. Deliberate application of mechanical force during transfer introduced crystalline defects and strain, creating discrete quantum emitters exhibiting localized excitonic behavior. To probe the emission properties of these quantum dots, scientists employed micro-photoluminescence (μPL) spectroscopy in a confocal geometry, achieving spatial resolution of 1.

5μm at cryogenic temperatures of 3. 8 K. Experiments focused on emission spectrally isolated from the broader monolayer exciton emission, specifically targeting a range below 1. 6755 eV. A representative quantum dot exhibited an exciton ground state energy of 1.

649 eV, characterized by a dominant zero-phonon line with a linewidth of 100 μeV and a broader feature arising from acoustic phonon interactions. To confirm the quantum nature of the emission, researchers performed a Hanbury Brown-Twiss (HBT) experiment, utilizing 2-ps Ti:Sapphire laser pulses to drive the quantum dot. The experiment revealed a second-order correlation function of 0. 11 ±0. 02 at zero delay, confirming single-photon emission. Analysis of the system dynamics involved solving the Lindblad master equation for an effective three-level system, capturing population transfer between exciton states, and suggesting the involvement of a metastable state in the relaxation dynamics.

The observation of Rabi oscillations confirms controlled manipulation of a quantum state, crucial for quantum applications. This work investigates Rabi oscillations arising in a quantum dot based on a WSe2 monolayer, receiving coherent excitation using picosecond laser pulses and probing photoluminescence from the ground state. Theoretical treatment, based on a three-level exciton model, reveals population transfer between exciton ground and excited states coupled by Coulomb interaction, demonstrating the resulting exciton ground state population.

Tungsten Diselenide Exhibits Controlled Rabi Oscillations

Researchers have demonstrated the emergence of Rabi oscillations within a single layer of tungsten diselenide, achieved by driving the material with precisely tuned laser pulses and observing the resulting emission of light. The team’s theoretical model accurately predicts the observed population changes and confirms control over the material’s quantum state through variations in laser parameters, establishing a pathway towards creating coherent control of light-emitting materials in two-dimensional semiconductors. Future research should focus on achieving coherent control of the material’s ground state and integrating these emitters with high-quality optical cavities to further enhance their performance and unlock their full potential for quantum technologies. While the current model does not fully account for the influence of vibrational modes, the researchers suggest that a more comprehensive treatment could refine the accuracy of their predictions. This advancement promises to contribute to the development of high-performance, on-demand single-photon sources for applications in quantum communication and computation.