Adjoint-optimized nanoscale light extractor for nitrogen-vacancy centers in diamond

• Main Authors: Wambold Raymond A., Yu Zhaoning, Xiao Yuzhe, Bachman Benjamin, Jaffe Gabriel, Kolkowitz Shimon, Choy Jennifer T., Eriksson Mark A., Hamers Robert J., Kats Mikhail A.
• Format: Article
• Language: English
• Published: De Gruyter 2020-11-01
• Series: Nanophotonics
• Subjects: adjoint optimization; color center; inverse design; purcell enhancement; quantum sensing; topological optimization
• Online Access: https://doi.org/10.1515/nanoph-2020-0387
• ISSN: 2192-8606; 2192-8614

We designed a nanoscale light extractor (NLE) for the efficient outcoupling and beaming of broadband light emitted by shallow, negatively charged nitrogen-vacancy (NV) centers in bulk diamond. The NLE consists of a patterned silicon layer on diamond and requires no etching of the diamond surface. Our design process is based on adjoint optimization using broadband time-domain simulations and yields structures that are inherently robust to positioning and fabrication errors. Our NLE functions like a transmission antenna for the NV center, enhancing the optical power extracted from an NV center positioned 10 nm below the diamond surface by a factor of more than 35, and beaming the light into a ±30° cone in the far field. This approach to light extraction can be readily adapted to other solid-state color centers.