EPSCoR Research Fellows: NSF: Plasmonic Cavity Nanostructures to Boost Single Photon Emission from Multilayered Hexagonal Boron Nitride

Efficient and compact single photon emission platforms operating at room temperature with ultrafast speed and high brightness are needed as fundamental components of the emerging quantum communication and quantum sensing technologies. However, so far, it has been particularly challenging to design practical deterministic single photon emitters based on nanoscale solid-state materials that meet both the fast emission rate and strong brightness demands.

The planned research aims to fabricate metallic nanocavities integrated with hexagonal boron nitride (hBN) flakes with defects acting as nanoscale single photon emitters (SPEs) at room temperature. The proposed project is conducted with a collaborator at Pennsylvania State University. The obtained research outcomes would significantly enhance the performance and efficiency of novel quantum devices development by providing fundamental understanding of the rich quantum phenomena at the nanoscale.

The research activities at the host site will help train the lead researcher's graduate students from the University of Nebraska-Lincoln (UNL) in using high-end facilities. Their exposure to cutting-edge research in quantum optics and applied aspects of quantum communication is part of the increasingly important workforce development. This project also supports the research projects within the Nebraska EPSCoR RII Track-1 Emergent Quantum Materials and Technologies Center.

Single-photon emitters are building blocks for various quantum technologies including quantum sensing and quantum communication. Significant developments over recent years led to the discovery of a variety of atom-like SPEs in solid-state platforms, such as defect-related color centers in wide bandgap materials (e.g., nitrogen vacancy centers in diamond).

Although substantial progress led to understanding and utilizing the quantum properties of SPEs, further advances are severely limited by difficulties in achieving the exact placement of quantum emitters, weak light collection due to the high refractive index of bulk substrates, slow emission dynamics, and large-scale integration. The focus of the project is on nanofabrication of plasmonic nanocavities and integrating them to emerging two-dimensional multilayered hBN material with the goal to create gap nano-plasmons enhanced single-photon emission rates.

The proposed work includes: (i) fabrication of hybrid plasmonic-hBN nanocavities at Pennsylvania State University, (ii) study the enhancement effect of the nanostructures on the quantum properties of SPEs at UNL, and (iii) perform finite element method (FEM) simulations to quantify the SPE-plasmon coupling coefficients as function of the nanocavity geometry and dimensions to determine the ideal spatial position of the metallic nanostructures. The made hybrid nanophotonic structures would create a rapid speedup and large enhancement in single photon emission that beats dephasing time and leads to the generation of indistinguishable photons needed for key quantum communication technologies such as quantum entanglement.

The lead researcher and students from UNL will be trained on the state-of-the-art research tools at Pennsylvania State University, including nanofabrication, advanced characterization tools, and FEM simulations.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.