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Transmissible topological edge states based on Su–Schrieffer–Heeger photonic crystals with defect cavities

Authors :
Yan Qiuchen
Ma Rui
Lyu Qinghong
Hu Xiaoyong
Gong Qihuang
Source :
Nanophotonics, Vol 13, Iss 8, Pp 1397-1406 (2024)
Publication Year :
2024
Publisher :
De Gruyter, 2024.

Abstract

Topological photonic crystals have great potential in the application of on-chip integrated optical communication devices. Here, we successfully construct the on-chip transmissible topological edge states using one-dimensional Su–Schrieffer–Heeger (SSH) photonic crystals with defect cavities on silicon-on-insulator slab. Different coupling strengths between the lateral modes and diagonal modes in photonic crystal defect cavities are used to construct the SSH model. Furthermore, two photonic SSH-cavity configurations, called α and β configurations, are designed to demonstrate the topological edge states. Leveraging the capabilities of photonic crystal transverse electric modes with on-chip transmission, we introduced a waveguide to excite a boundary defect cavity and found that the transmission peak of light, corresponding to the topological edge state, can be received in another boundary defect cavity, which is caused by the tunnel effect. Moreover, the position of this peak experiences a blue shift as the defect cavity size increases. Therefore, by tuning the size of the SSH defect cavity, on-chip wavelength division multiplexing function can be achieved, which is demonstrated in experiments. The ultrafast response time of one operation can be less than 20 fs. This work harmonizes the simplicity of one-dimensional SSH model with the transmissibility of two-dimensional photonic crystals, realizing transmissible on-chip zero-dimensional topological edge states. Since transmission peaks are highly sensitive to defect cavity size, this configuration can also serve as a wavelength sensor and a reconfigurable optical device, which is of substantial practical value to on-chip applications of topological photonics.

Details

Language :
English
ISSN :
21928614
Volume :
13
Issue :
8
Database :
Directory of Open Access Journals
Journal :
Nanophotonics
Publication Type :
Academic Journal
Accession number :
edsdoj.93cc002a16469a9bcdc9f53c806364
Document Type :
article
Full Text :
https://doi.org/10.1515/nanoph-2023-0744