Effects of Floquet Engineering on the Coherent Exciton Dynamics in Monolayer WS
arXiv:2301.12599 · doi:10.1021/acsnano.3c01318
Abstract
Coherent optical manipulation of electronic bandstructures via Floquet Engineering is a promising means to control quantum systems on an ultrafast timescale. However, the ultrafast switching on/off of the driving field comes with questions regarding the limits of validity of the Floquet formalism, which is defined for an infinite periodic drive, and to what extent the transient changes can be driven adibatically. Experimentally addressing these questions has been difficult, in large part due to the absence of an established technique to measure coherent dynamics through the duration of the pulse. Here, using multidimensional coherent spectroscopy we explicitly excite, control, and probe a coherent superposition of excitons in the and valleys in monolayer WS. With a circularly polarized, red-detuned, pump pulse, the degeneracy of the and excitons can be lifted and the phase of the coherence rotated. We demonstrate phase rotations during the 100 fs driving pulse that exceed , and show that this can be described by a combination of the AC-Stark shift of excitons in one valley and Bloch-Siegert shift of excitons in the opposite valley. Despite showing a smooth evolution of the phase that directly follows the intensity envelope of the pump pulse, the process is not perfectly adiabatic. By measuring the magnitude of the macroscopic coherence as it evolves before, during, and after the pump pulse we show that there is additional decoherence caused by power broadening in the presence of the pump. This non-adiabaticity may be a problem for many applications, such as manipulating q-bits in quantum information processing, however these measurements also suggest ways such effects can be minimised or eliminated.
References in corpus (34)
- Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
- The Valley Hall Effect in MoS2 Transistors
- Optical Generation of Excitonic Valley Coherence in Monolayer WSe2
- Observation of Floquet-Bloch states on the surface of a topological insulator
- Floquet Engineering of Quantum Materials
- Light-induced anomalous Hall effect in graphene
- Valley-selective optical Stark effect in monolayer WS2
- Intrinsic Exciton Linewidth in Monolayer Transition Metal Dichalcogenides
- Avoiding power broadening in optically detected magnetic resonance of single NV defects for enhanced DC-magnetic field sensitivity
- Ultrafast Generation of Pseudo-magnetic Field for Valley Excitons in WSe2 Monolayers
- Direct Measurement of Exciton Valley Coherence in Monolayer WSe
- Ultrafast Manipulation of Valley Pseudospin
- Neutral and Charged Inter-Valley Biexcitons in Monolayer MoSe
- Ultrafast melting of a charge-density wave in the Mott insulator 1T-TaS2
- Electroluminescence from multi-particle exciton complexes in transition metal dichalcogenide semiconductors
- Large, valley-exclusive Bloch-Siegert shift in monolayer WS2
- Polaritonic neuromorphic computing outperforms linear classifiers
- Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe2
- All-Optical Materials Design of Chiral Edge Modes in Transition-Metal Dichalcogenides
- Observation of intervalley biexcitonic optical Stark effect in monolayer WS2
- Tuning the Ultrafast Spin Dynamics in Carrier-Density-Controlled Ferromagnets
- Floquet engineering of strongly-driven excitons in monolayer tungsten disulfide
- Exciton-polaron interactions in monolayer WS
- A Single Charged Quantum Dot in a Strong Optical Field: Absorption, Gain, and the AC Stark Effect
- Disentangling the effects of doping, strain and defects in monolayer WS2 by optical spectroscopy
- Valley-selective optical Stark effect probed by Kerr rotation
- Controlling Floquet states on ultrashort time scales
- Ultrafast valley-selective coherent optical manipulation with excitons in WSe and MoS monolayers
- Direct Measurement of Biexcitons in Monolayer WS2
- Exciton-coherence generation through diabatic and adiabatic dynamics of Floquet state
- Coherent Dynamics of Floquet-Bloch States in Monolayer WS2 Reveals Fast Adiabatic Switching
- Preparation and probing of the ground state coherence in Rubidium
- Quantum interference between the optical Stark effect and resonant harmonic generation in WS2
- Semiconductor Bloch equation analysis of optical Stark and Bloch-Siegert shifts in monolayers WSe and MoS