Destructive Photon Echo Formation in Six-Wave Mixing Signals of a MoSe2 Monolayer

Monolayers of transition metal dichalcogenides display a strong excitonic optical response. Additionally encapsulating the monolayer with hexagonal boron nitride allows to reach the limit of a purely homogeneously broadened exciton system. On such a MoSe2-based system, ultrafast six-wave mixing spectroscopy is performed and a novel destructive photon echo effect is found. This process manifests as a characteristic depression of the nonlinear signal dynamics when scanning the delay between the applied laser pulses. By theoretically describing the process within a local field model, an excellent agreement with the experiment is reached. An effective Bloch vector representation is developed and thereby it is demonstrated that the destructive photon echo stems from a destructive interference of successive repetitions of the heterodyning experiment.

Automated summary

Monolayers of transition metal dichalcogenides exhibit strong excitonic optical response and when encapsulated with hexagonal boron nitride, they can achieve a purely homogeneously broadened exciton system. Ultrafast six-wave mixing spectroscopy on a MoSe2-based system revealed a novel destructive photon echo effect, which arises from destructive interference in successive repetitions of the heterodyning experiment.