Designing Two-Dimensional KBBF Family Second-Harmonic Generation Monolayers

Two-dimensional nonlinear optics materials are key to miniaturization of laser devices. Layered structure of KBe₂BO₃F₂ (KBBF) is regarded as a point cutting into low dimension. Two-dimensional (2D) AlBeBO₃F₂, the layered structure without potassium in KBBF and half beryllium substitute by aluminum, was predicted to work as a second-harmonic generation (SHG) material in >200 nm range in UV and visible regions. The similarity with bulk is that BO₃ and F groups are making main contribution to the SHG effect, while the dimensionality compensates the negativity in bulk on SHG enhancement. Other modification strategies in the KBBF family are also expected in 2D systems.