Hybrid metasurfaces consist of phase change material Ge2Sb2Te5 (GST) and amorphous silicon metasurface is utilized for tunable third harmonic generation (THG). Hybrid metasurfaces support Fano resonance with experimental quality factor (Q-factor ≈ 125) at the fundamental pump wavelength around 1210 nm. Gradual multistate tuning of THG emission is obtained at its intermediate states, ranging from turn-on state in the amorphous state and turn-off state in the crystalline state. The measured conversion efficiency of η = 2.9 × 10−6% is achieved. The obtained efficiency is 32 times more than that of a GST-based Fabry–Pèrot cavity under a similar pump laser power. Results show the strength of exploring GST-based hybrid dielectric metasurfaces for tunable nonlinear optical metasurfaces.

Read More