Journal article · Preprint article
Maximizing the quality factor to mode volume ratio for ultra-small photonic crystal cavities
Small manufacturing-tolerant photonic crystal cavities are systematically designed using topology optimization to enhance the ratio between the quality factor and mode volume, Q/V. For relaxed manufacturing tolerance, a cavity with a bow-tie shape is obtained which confines light beyond the diffraction limit into a deep-subwavelength volume.
Imposition of a small manufacturing tolerance still results in efficient designs, however, with diffraction-limited confinement. Inspired by numerical results, an elliptic ring grating cavity concept is extracted via geometric fitting. Numerical evaluations demonstrate that for small sizes, topology-optimized cavities enhance the Q/V-ratio by up to two orders of magnitude relative to standard L1 cavities and more than one order of magnitude relative to shape-optimized L1 cavities.
An increase in cavity size can enhance the Q/V-ratio by an increase in the Q-factor without a significant increase in V. Comparison between optimized and reference cavities illustrates that significant reduction of V requires big topological changes in the cavity.
Language: | English |
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Publisher: | AIP Publishing LLC |
Year: | 2018 |
Pages: | 241101 |
ISSN: | 10773118 and 00036951 |
Types: | Journal article and Preprint article |
DOI: | 10.1063/1.5064468 |
ORCIDs: | Wang, Fengwen , Mørk, Jesper , Sigmund, Ole , Christiansen, Rasmus Ellebæk and Yu, Yi |