Polarization resolved spatial near-field mapping of optical modes in an on-chip rolled-up bottle microcavity

Abstract

A detailed optical near-field mapping of the spatial distribution of two sets of linearly polarized modes in a vertically rolled-up bottle microcavity is presented. We find different effective axial potential widths depending on the polarization state by coupling a tapered fiber to the on-chip microcavity and show that we can selectively excite modes out of a rich axial mode spectrum. Our results are supported by a theoretical model and help to promote future applications of rolled-up bottle microcavities in on-chip integrated optical networks, where these tube cavities can, in principle, be used to transfer signals horizontally along the tube axis or vertically between stacked photonic layers.