Source: School of Physics
Written by: School of Physics
Edited by: Wang Dongmei

Uncontrollable light scattering in silicon-on-insulator (SOI) is one of the issues, limiting the performance improvement of nanophotonic devices. The exploration of topological photonics can achieve robust light transport in nanophotonics, leading an intriguing way to overcome such limitation. Thus demonstration of topologically optical characteristics in SOI has attracted much attention recently, as a target to integrated topological nanophotonics. However, SOI implementation of topological photonic structures still remains much challenge, in particular for subwavelength strategy which is a key factor for high-density integration and device miniaturization.

Scientists with the School of Physics and State Key Laboratory of Optoelectronic Materials and Technologies (OEMT) in Sun Yat-sen University (SYSU) have answered this question in the affirmative. “The key problem is how to maintain topologically nontrivial phase in the plane of chip and suppress the out-of-plane radiation at the same time.” says Jianwen Dong who led this study. “We develop valley physics into SOI platform to solve the issue.” Followed such mechanism, they have achieved valley-dependent topological interface in photonic crystal slab, leading to scattering-suppressed robust transport at telecommunication wavelength. In addition, they have experimentally demonstrated topological photonic routing, due to unidirectional excitation of the edge state from the phase vortex of a nanoscale microdisk.

Dong, who is elected in NSFC Excellent Young Scientists and Cheung Kong Scholar Youth Professor, is the corresponding author of a paper describing this physics research in the journal Nature Communications. The paper is titled “A silicon-on-insulator slab for topological valley transport” and see detailed results through the link of https://www.nature.com/articles/s41467-019-08881-z. This work is independently accomplished by Prof. Dong’s team and SYSU is the unique affiliation.
 

"Our subwavelength strategy enables to design compact-size topological SOI devices that allows integration with other optoelectronic devices on a single chip.” says Xintao He, the first author of the Nat. Commun. paper and the associate research fellow of Professor Dong’s group. Valley topological nanophotonics not only show the promising applications for the prototype of robustly integrated devices, but also open a new door towards the observation of non-trivial states even in non-Hermitian systems.

This research was supported by NSFC, Guangdong grant, Guangzhou grant, and OEMT.

Additional Information
Jianwen Dong can be reached for more about the research and comment at dongjwen@mail.sysu.edu.cn and http://spe.sysu.edu.cn/dgroup/.