Quantum Research Projects Funded by the Joint Task Force Initiative

Mapping quantum defects in diamond at nanoscale resolution with a scannable plasmonic cavity


PIs and Institutions: Jeffrey Guest, Argonne; Alexander High, UChicago

Description: In this proposed work, we will utilize an atomic force microscope (AFM) with a metallic probe tip to generate a nanoscale and scannable plasmonic cavity to map and interrogate single atomic defects in ultrathin diamond membranes. Plasmonic cavities can confine optical energy to well below the diffraction limit and dramatically enhance light-matter interactions. We plan to utilize the experimental platform developed at the CNM at Argonne (Guest) to image and interrogate single atomic defects in diamond membranes developed at University of Chicago (High). Atomic defects in diamond can be utilized as stable, high-fidelity quantum registers in which quantum information is encoded in electronic and nuclear spin states. Furthermore, the quantum information stored in these defects can be entangled with single emitted optical photons, a simple mechanism for generating entanglement between separate spin states. However, optical interfaces with quantum defects in diamond utilize nanophotonic or far-field optics that are diffraction-limited, preventing individual readout in high-density systems and limiting achievable optical fields. Our approach will provide not only sub-nm cavity length and lateral position control, but allow us modify and optimize the coupling in real-time, opening a new regime for a wide array of strong field and high precision experiments.

Integrated quantum plasmonic platform for erbium ions


PIs and Institutions: Alan Dibos, Argonne; Tian Zhong, UChicago 

Description: We propose a novel quantum plasmonic cavity platform to optically address individual erbium ions for use as a telecom quantum node in quantum networks. The nature of these plasmonic nanocavities should make them robust to fabrication imperfections and facilitate manufacturing multiple cavities with the same resonant wavelength, which is challenging for conventional photonic cavities. We aim to: (1) demonstrate large improvements in brightness for individual ions, (2) systematically measure the quantum coherence properties of these ions in the presence of a nearby metallic film, and (3) generate indistinguishable telecom photons from ions in separate cavities for long-distance quantum entanglement. This newly formed collaboration is essential to streamline the challenging materials growth, ambient device characterization, and sophisticated cryogenic optical measurements. This collaboration leverages the unique growth and nanofabrication resources in Argonne’s Center for Nanoscale Materials and the complex fiber cryogenic measurement capabilities at UChicago’s Pritzker School of Molecular Engineering.