Silicon photonic bowtie cavities with atomic-scale dimensions

Recent progress in photonics has highlighted the importance of miniaturization, particularly in achieving dielectric bowtie cavities with small mode volumes, which were previously limited to plasmonics. This study presents a novel method that combines top-down nanopatterning and bottom-up self-assembly to fabricate photonic cavities with atomic-scale dimensions. By utilizing surface forces, we demonstrate waveguide-coupled silicon photonic cavities with high quality factors, confining light to atomic-scale air gaps with an aspect ratio above 100, corresponding to mode volumes more than 100 times below the diffraction limit. These cavities exhibit unprecedented figures of merit for enhancing light-matter interaction and enable charting hitherto inaccessible regimes of solid-state quantum electrodynamics.