Integration of Nanoemitters onto Photonic Structures by Guided Evanescent-Wave Nano-Photopolymerization

Abstract

In this article, we demonstrate the feasibility of self-positioning nanoemitters onto optical waveguides by visible-light nanoscale photopolymerization. A light-sensitive material containing nanoemitters is photopolymerized at interfaces by using the evanescent field of the light propagating in photonic structures. By exploiting this method, it is possible to pattern polymeric ridges containing CdSe/ZnS nanocrystals (NCs) directly on top of optical guiding structures. Photopolymerization experiments have been performed in the case of a single ion-exchange glass waveguide (IEx WG) and of a double waveguide made of the IEx WG with a thin titanium dioxide film fabricated on top of it. Atomic force microscopy (AFM) and spectroscopy analyses highlight the reliability and reproducibility of the fabrication technique. Continuous ridges of controlled thickness have been realized on top of a single waveguide interface with thicknesses as small as 18 nm, thus thick enough to contain only a photoluminescent NC monolayer in the vertical direction. In the presence of the double waveguide (TiO2 layer on top of the IEx WG), AFM measurements reveal that the thickness of the photopolymerized ridge has a sinusoidal modulation. This is due to a light beating phenomenon theoretically predicted in the case of light propagating in coupled waveguides. In our case, the light beating can be efficiently exploited to photopolymerize ridges with modulated thickness. Overall, the flexibility of the reported nanoscale fabrication technique paves the way toward the controlled positioning of single nanoemitters in proximity of nanoantennas or other elaborate plasmonic/photonic structures.

A comprehensive optical analysis of nanoscale structures: from thin films to asymmetric nanocavities

“…This trend in research is thus promoting the evolution of comprehensive numerical packages that provide extremely accurate descriptions of physical processes. [1][2][3] Handily, commercial packages now provide highly reliable modeling of phenomena like structural or uid behaviors, [4][5][6][7] wave propagation, [8][9][10][11][12][13] and thermal transport, [14][15][16] to name but a few. As a consequence, the availability of such powerful tools is modifying the way research is performed, eventually suggesting new possibilities to optimize the scientic procedure itself.…”

Recent Advances on Nanocomposite Resists With Design Functionality for Lithographic Microfabrication

“…In particular, UCNPs based on the energy transfer mechanism between sensitized and activator dopants have been extensively developed in recent years due to the capabilities of the chemical synthesis, their chemical endurance, low toxicity and excellent optical stability (Wang et al, 2010;Chen et al, 2014). Luminescent NCPRs have many applications: photo-curing of PRs with embedded QDs has been studied for on-chip detection of heavy metal ions (Xu et al, 2013), bar-coding particles (Zhao et al, 2011), development of high quality displays (Li et al, 2019c) and deterministic integration of quantum emitters into waveguides (Lio et al, 2019;Xu et al, 2020b), nanoantennas (Broussier et al, 2019) and remotely controllable magnetic structures (Au et al, 2020). A recent review by Smith et al contains a section on lithographically pattered QD NCPRs (Smith et al, 2019).…”

Conceptual Implementation of a Photonic–Plasmonic Transistor onto a Structured Nano‐Guided Hybrid System

“…It absorbs visible light in a range from 400 to 540 nm, with a peak at 530 nm, and emits light at 590 nm. The technique allows realizing polymer ridges containing nanoemitters with a restrained thickness as low as 18 ± 2 nm …”