Open AccessUltra-high quality-factor resonators with perfect azimuthal modal-symmetry
Author(s) -
Nikolaj Moll,
Thilo Stöferle,
Sophie Schönenberger,
Rainer F. Mahrt
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.020998
Subject(s) - resonator , optics , grating , chirp , symmetry (geometry) , azimuth , q factor , quality (philosophy) , modal , wavelength , physics , materials science , concentric , geometry , laser , mathematics , quantum mechanics , polymer chemistry
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.