External Strain Enabled Post-Modification of Nanomembrane-Based Optical Microtube Cavities

Abstract

Optical microtube cavities formed by self-rolling of pre-strained nanomembranes feature unique optical resonance properties for both fundamental and applied research. A post-fabrication treatment of the microcavities made of rolled-up nanomembranes is attractive in order to better manipulate and control the optical modes therein. Here, we report a new approach of modifying the resonant modes by applying external strain using a stretchable polymer substrate. The properties of both azimuthal and higher order axial modes are systematically investigated by varying external strain along the tube axial direction. The post-treatment process leads to a spectral redshift and improvement of quality factors, which is attributed to a modification of tube shape and interlayer compactness. For tubes with axial confinement, the measurements suggest that both the eigenenergies and mode spatial distributions of optical axial modes get significantly modified after applying the external strain. Our numerical calculation res...