Geometry Dependent Evolution of the Resonant Mode in ZnO Elongated Hexagonal Microcavity

We have developed a novel but simple approach to obtain ZnO microcombs with parallelogram stems and elongated hexagonal branches. We found that the present elongated hexagonal microcavity exhibited quite different features for its optical resonant modes due to the broken hexagonal symmetry. The resonant mode evolution of such microcavity was investigated systemically by using a spatially resolved spectroscopic technique. Theoretical analyses based on the plane wave mode and FEM simulations agreed well with the experimental results. We believe that our research allows us to have a deeper understanding of the controllable growth of novel optical cavities and the shape-dependent optical resonant modes.