Bottom-up Fabrication of 2D Rydberg Exciton Arrays in Cuprous Oxide

TL;DR

This paper presents a scalable, bottom-up fabrication method for creating site-selective arrays of Cuprous Oxide microparticles that host Rydberg excitons, advancing integrated quantum photonic technologies.

Contribution

It introduces a CMOS-compatible growth technique for deterministic assembly of Cuprous Oxide arrays with observed Rydberg excitons up to n=5, enabling scalable quantum device development.

Findings

Successful fabrication of Cuprous Oxide microparticle arrays.

Observation of Rydberg excitons up to n=5 in arrays.

Robust and reproducible spectral properties across large arrays.

Abstract

Solid-state platforms provide exceptional opportunities for advancing on-chip quantum technologies by enhancing interaction strengths through coupling, scalability, and robustness. Cuprous oxide ($\text{Cu}_{2}\text{O}$) has recently emerged as a promising medium for scalable quantum technology due to its high-lying Rydberg excitonic states, akin to those in hydrogen atoms. To harness these nonlinearities for quantum applications, the confinement dimensions must match the Rydberg blockade size, which can reach several microns in $\text{Cu}_{2}\text{O}$. Using a CMOS-compatible growth technique, this study demonstrates the bottom-up fabrication of site-selective arrays of $\text{Cu}_{2}\text{O}$ microparticles. We observed Rydberg excitons up to the principal quantum number $n$=5 within these $\text{Cu}_{2}\text{O}$ arrays on a quartz substrate and analyzed the spatial variation of their spectrum across the array, showing robustness and reproducibility on a large chip. These results lay the groundwork for the deterministic growth of $\text{Cu}_{2}\text{O}$ around photonic structures, enabling substantial light-matter interaction on integrated photonic platforms and paving the way for scalable, on-chip quantum devices.