Y. Gao, F. Lei, M. Girardi, Z. Ye, R. Van Laer, V. Torres-Company, J. Schröder. “Compact lithium niobate microring resonators in the ultrahigh Q/V regime,” Optics Letters 48 (15) (2023). https://opg.optica.org/ol/abstract.cfm?uri=ol-48-15-3949