Nonlinear spectroscopy of excitonic states in transition metal dichalcogenides

Abstract

Second-harmonic generation (SHG) is a well-known nonlinear spectroscopy method to probe electronic structure, specifically, in transition metal dichalcogenide (TMDC) monolayers. This work investigates the nonlinear dynamics of a strongly excited TMDC monolayer by solving the time evolution equations for the density matrix. It is shown that the presence of excitons qualitatively changes the nonlinear dynamics leading, in particular, to a huge enhancement of the nonlinear signal as a function of the dielectric environment. It is also shown that the SHG polarization angular diagram and its dependence on the driving strength are very sensitive to the type of exciton state. This sensitivity suggests that SHG spectroscopy is a convenient tool for analyzing the fine structure of excitonic states.

13 pages, 5 figures

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Cited by in corpus (3)

• Emergent bright excitons with Rashba spin-orbit coupling in atomic monolayers
• Excitonic effects in time-dependent density functional theory from zeros of the density response
• Determining the complex second-order optical susceptibility in macroscale van der Waals heterobilayers