title: Symmetrically glass-clad photonic crystal nanocavities with ultrahigh quality factors.
abstract: We design and fabricate ultra-high-quality (Q) photonic nanocavities in a symmetrically glass-clad silicon (Si) two-dimensional (2D) photonic crystal (PhC) structure. We theoretically investigate the dependence of the refractive index of the glass on the Q factors for asymmetric and symmetric structures. We show that the index-symmetric distribution of the glass is a critical factor to realize ultrahigh Q factors for glass-clad 2D PhC structures. We fabricate symmetrically glass-clad Si PhC nanocavities and achieve a record Q factor of 1×10(6), comparable with the highest Q factors of nanocavities in air-bridge structures.
authors.affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan. songwiz@skku.edu
authors.forename: Bong-Shik
authors.initials: BS
authors.lastname: Song
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Jeon
authors.forename: Susumu
authors.initials: S
authors.lastname: Noda