Efficient Harnessing of Light from Nanoscale Emitters Deterministically Placed through Polymer-Pen Lithography at the Focus of 3D-Printed Ellipsoidal Micro-Lenses

Collecting significant and measurable signals from the typically omni-directional emission of nanoscale emitters is challenging. To improve the collection efficiency, it is essential to deterministically place the emitters in desired locations, and design mode-converters to match the modes of emission to those of the collection system. In this paper, we propose the deterministic placement of nanoscale emitters using a pick-and-place technique called polymer-pen lithography. We demonstrate the concept with upconversion nanoparticles placed deterministically at the focus of 3D-printed ellipsoidal micro-lenses. A significant part of the forward-going emission is collimated leading to increased collection efficiency even at low numerical apertures of the collecting optics. The proposed approach lends itself to hybrid integration for fiber-to-chip and on-chip applications.