2025/04/28 by Priyash Barya, Barya, Priyash, Ashwith Prabhu +7 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photorefractive and Nonlinear Optics #Quantum Physics (quant-ph) #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.2504.19465
openalex publication_date 2025/04/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
High-Q nanophotonic resonators are crucial for many applications in classical and quantum optical processing, communication, sensing, and more. We achieve ultra-high quality factors by preparing a highly transparent and strongly dispersive medium within a resonator, causing a reduction in the group velocity that leads to a nearly three order of magnitude increase in the quality factor. We implement this via spectral hole burning in erbium-doped thin-film lithium niobate microring resonators, and show Q-factors exceeding 108. Additionally, we show that the interplay between the spectrally narrowed resonance and the broader bare resonance produces a Fano lineshape, which we dynamically control via electro-optic tuning. Finally, we present a theoretical model for our experimentally observed resonator linewidths, which are not well-described by the standard Bloch equations. Our results show a dramatic reduction in the erbium dephasing rate under a strong optical drive, leading to much narrower linewidths than would otherwise be expected given the large circulating intensity in the resonator.