Nonlinear Exciton-Mie Coupling in Transition Metal Dichalcogenide Nanoresonators

Thanks to a high refractive index, giant optical anisotropy, and pronounced excitonic response, bulk transition metal dichalcogenides (TMDCs) have recently been discovered to be an ideal foundation for post-silicon photonics. The inversion symmetry of bulk TMDCs, on the other hand, prevents their use in nonlinear-optical processes such as second-harmonic generation (SHG). To overcome this obstacle and broaden the application scope of TMDCs, MoS2$_2$ nanodisks are engineered to couple Mie resonances with C-excitons. As a result, their alliance produces 23-fold enhancement of SHG intensity with respect to the resonant SHG from a high-quality exfoliated MoS2$_2$ monolayer under C-exciton excitation. Furthermore, SHG demonstrates a strongly anisotropic response typical of a MoS2$_2$ monolayer due to the single-crystal structure of the fabricated nanodisks, providing a polarization degree of freedom to manipulate SHG. Hence, these results significantly improve the potential of bulk TMDCs enabling an avenue for next-generation nonlinear photonics.

Automated summary

Recent discoveries have shown that bulk TMDCs have excellent properties for post-silicon photonics, such as high refractive index, giant optical anisotropy, and pronounced excitonic response. However, their inversion symmetry hinders their use in nonlinear-optical processes. By engineering MoS2 nanodisks to couple Mie resonances with C-excitons, researchers have overcome this obstacle and achieved a 23-fold enhancement of SHG intensity. Additionally, the SHG demonstrates a strong anisotropic response typical of a MoS2 monolayer.