Synthesis of second-order nonlinearities in dielectric-semiconductor-dielectric metamaterials

摘要

We demonstrate a large effective second-order nonlinear optical susceptibility in electronic optical metamaterials based on sputtered dielectric-semiconductor-dielectric multilayers of silicon dioxide/amorphous silicon (a-Si)/aluminum oxide. The interfacial fixed charges (Q_f) with opposite signs on either side of dielectric-semiconductor interfaces result in a non-zero built-in electric field within the a-Si layer, which couples to the large third-order nonlinear susceptibility tensor of a-Si and induces an effective second-order nonlinear susceptibility tensor Ⅹ_(eff)~((2)). The value of the largest components of the effective Ⅹ_(eff)~((2)) tensor, i.e.,Ⅹ~((2))_(zzz), is determined experimentally to be 2 pm/V for the as-fabricated metamaterials and increases to 8.5 pm/V after the post-thermal annealing process. The constituents and fabrication methods make these metamaterials CMOS compatible, enabling efficient nonlinear devices for chip-scale silicon photonic integrated circuits.