Tunable second harmonic generation from bianisotropic plasmonic metamolecule via utilizing phase change materials

In this work, we utilize phase change materials to achieve tunable second harmonic generation from magnetic resonance in bianisotropic plasmonic metamolecules. As a proof-of-concept, we fill the gap of gold split ring resonators (SRRs) with Ge2Se2Te5 (GST); the second harmonic wavelength can be tuned over 400 nm in the telecom regime when GST gradually changes from amorphous to crystalline state. According to the equivalent circuit model, we demonstrate that the second harmonic wavelength and its tunable range can be engineered through the capacitance coupling strength in gold SRRs. Our results may suggest a wide range of potential applications of nonlinear nanooptics.