Presentation Information
[9a-PA4-20]Giant Enhancement of Second-Harmonic Generation with Preserved Valley Properties
in Monolayer MoS2 on Metal-Insulator Nanocavity Substrates
〇Ryoichi Sakata1,2, Keisuke Shinokita1,2 (1.IMS, 2.SOKENDAI)
Keywords:
Monolayer MoS2,Second-harmonic generation,Nanocavity
Monolayer transition metal dichalcogenides (TMDs) exhibit unique optical properties, but their second-harmonic generation (SHG) efficiency is inherently low due to their atomic thickness. In this study, we developed a metal-insulator (MI) nanocavity substrate with precisely designed near-field enhancement and interference effects to achieve both giant SHG enhancement and robust valley control. We transferred a monolayer MoS2 onto the optically optimized MI substrate. Polarization-resolved SHG measurements demonstrated a giant enhancement of approximately 150-fold compared to a conventional SiO2 substrate while maintaining clear six-fold symmetry. Furthermore, a high degree of circular polarization was preserved, indicating that the intrinsic valley selection rules of monolayer MoS2 are protected despite the strong near-field enhancement. These results offer an efficient light-control platform for future nonlinear valleytronic devices.