1 research outputs found
Exciton-Sensitized Second-Harmonic Generation in 2D Heterostructures
The
efficient optical second-harmonic generation (SHG) of two-dimensional
(2D) crystals, coupled with their atomic thickness, which circumvents
the phase-match problem, has garnered considerable attention. While
various 2D heterostructures have shown promising applications in photodetectors,
switching electronics, and photovoltaics, the modulation of nonlinear
optical properties in such heterosystems remains unexplored. In this
study, we investigate exciton-sensitized SHG in heterobilayers of
transition metal dichalcogenides (TMDs), where photoexcitation of
one donor layer enhances the SHG response of the other as an acceptor.
We utilize polarization-resolved interferometry to detect the SHG
intensity and phase of each individual layer, revealing the energetic
match between the excitonic resonances of donors and the SHG enhancement
of acceptors for four TMD combinations. Our results also uncover the
dynamic nature of interlayer coupling, as made evident by the dependence
of sensitization on interlayer gap spacing and the average power of
the fundamental beam. This work provides insights into how the interlayer
coupling of two different layers can modify nonlinear optical phenomena
in 2D heterostructures