Enhancement of the Second Harmonic Generation from WS₂ Monolayers by Cooperating with Dielectric Microspheres

Abstract Herein, a 20‐fold enhancement of the optical second harmonic generation (SHG) from WS₂ monolayers by cooperating with SiO₂ dielectric microspheres (MSs) is reported. Detailed experiment and simulation studies indicate that the SHG enhancement is dominantly originated by the enhanced excitation intensity and enlarged collection efficiency produced by the SiO₂ MSs. The size effect of the SiO₂ MS on the SHG enhancement is also systematically investigated. Moreover, the SHG enhancement is found to be very sensitive to the surrounding refractive index of the SiO₂ MS, which advocates great promise for the photonic sensing applications. This work provides a low‐cost and efficient approach to enhancing the SHG emission, and demonstrates great potential for functional nanodevices based on hybrid dielectric structures.