Tracking the photoinduced dynamics of a dark excitonic state in single-layer WS${}_2$ via resonant Autler-Townes splitting

Abstract

Excitons in a monolayer transition metal dichalcogenide (1L-TMD) are highly bound states characterized by a Rydberg-like spectrum of discrete energy levels. Among these, states with odd-parity are known as dark excitons due to selection rules, which make their stationary and transient characterization challenging using linear optical techniques. Here, we demonstrate that the dynamics of a 2p dark excitonic state in 1L-WS${}_2$ can be directly retrieved by measuring the Autler-Townes splitting of bright states in a three-pulse experiment. The splitting of the bright 1s excitonic state, observed by detuning a mid-infrared control field across the 1s-2p transition, provides an accurate characterization of the 2p state. Following carrier photoinjection, we observe a qualitatively different dynamics of the 1s and 2p levels, which is indicative of symmetry-dependent screening and exciton-exciton interactions. These findings provide new insights into many-body effects in TMDs, offering potential avenues for advancing the next generation optoelectronics.

References in corpus (24)

• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Excitons in atomically thin transition metal dichalcogenides
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• Exciton Binding Energy of Monolayer WS2
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Photo-Induced Bandgap Renormalization Governs the Ultrafast Response of Single-Layer MoS2
• Dark excitons in transition metal dichalcogenides
• Van der Waals Heterostructure Polaritons with moiré-Induced Nonlinearity
• Exciton Dynamics in Monolayer Transition Metal Dichalcogenides
• Observation of exciton redshift-blueshift crossover in monolayer WS2
• The ultrafast onset of exciton formation in 2D semiconductors
• Strain, doping and electronic transport of large area monolayer MoS2 exfoliated on gold and transferred to an insulating substrate
• Exciton Relaxation Cascade in Two-dimensional Transition-metal dichalcogenides
• Intrinsic Lifetime of Higher Excitonic States in Tungsten Diselenide Monolayers
• Mapping of the dark exciton landscape in transition metal dichalcogenides
• Valley-dependent Exciton Fine Structure and Autler-Townes Doublets from Berry Phases in Monolayer Molybdenum Diselenide
• Coherent dynamics and mapping of excitons in single-layer MoSe${}_2$ and WSe${}_2$ at the homogeneous limit
• Optical fingerprint of dark 2p-states in transition metal dichalcogenides
• Ultrafast valley-selective coherent optical manipulation with excitons in WSe${}_2$ and MoS${}_2$ monolayers
• Exciton-exciton interactions in van der Waals heterobilayers
• Probing Dark Excitons in Monolayer MoS${}_2$ by NonLinear Two-Photon Spectroscopy
• Exciton-exciton Interaction in Monolayer MoSe${}_2$ from Mutual Screening of Coulomb Binding
• Visible pump -- mid infrared pump -- broadband probe: development and characterization of a three-pulse setup for single-shot ultrafast spectroscopy at 50 kHz