  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.
