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Updated: Jun 17, 2026

Fabrication of Silica Ultra High Quality Factor Microresonators
Published on: July 2, 2012
Ultra-high quality-factor resonators with perfect azimuthal modal-symmetry
Nikolaj Moll1, Thilo Stöferle, Sophie Schönenberger
1IBM Research - Zurich, 8803 Rüschlikon, Switzerland. nim@zurich.ibm.com
Abstract:
We study circular grating resonators (CGRs) which are formed by a central defect surrounded by concentric rings composing a grating and which display perfect azimuthal modal-symmetry. Because of their radial symmetry they exhibit a complete band gap for a minimal index contrast. However, as is the case for all 2D resonators their quality factors are limited by vertical losses. To reduce the vertical losses we introduce a chirp of the grating period by reducing it towards the central defect. The chirped CGRs exhibit drastically improved quality factors of up to tens of millions with a modal volume of a few cubic wavelengths.
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