Enhancing emission in a QD–nanodisk system via the alignment of the orientation of excitons with the polarization of Mie modes

Abstract

A Ge quantum dot (QD)–resonator system is an attractive solution for the Si-based emitter applied in monolithic optical–electronic integrated circuits, in which efficient coupling of QDs and cavity modes is crucial for achieving significant emission enhancement. Here, we present unique emission characteristics of a Ge QD–nanodisk array system based on the spatial matching of the two components. In this system, the two-order-of-magnitude emission enhancement is derived from self-assembled QDs, which is related to the orientation of excitons in QDs coinciding with a vertical-polarized Mie mode. In addition, the emission efficiency is also strongly dependent on the position of the QDs in nanodisks. As the orientation of the emitter is matched with the polarized mode, and the QD is located at the maximum of the field, optimal spatial matching can be achieved. These experimental and simulated results demonstrate the importance of spatial matching between emitters with proper polarization and cavity modes, which promises the realization of efficient on-chip light sources.