Investigating position-dependent chiral light-matter interactions

The chiral light-matter interaction between photonic nanostructures and quantum emitters could help enable spin-photon interfaces for quantum information processing and communication. For the first time, Xiao et al. investigated position dependence in cross waveguides, a photonic nanostructure, embedded with quantum dots, the quantum emitters.

With both numerical simulation and experiment, the authors demonstrated the position-dependent chiral-light matter interactions between quantum dots chirally coupled to a cross waveguide. The position of the quantum dot in the waveguides determines its spin momentum and chiral contrast.

Measuring chiral properties of the device from four quantum dots in different positions, they found the cross waveguide can be used as a one-way unidirectional waveguide and a circularly polarized beam splitter.

“Our work exploits position dependence in cross waveguides to achieve different unidirectional and polarization-deterministic emissions, leading to an extension of the functionality and application scenarios of the simple structure,” said author Xiulai Xu. “This position-dependent chiral coupling effect is well-characterized and robust, which paves way for spin-to-path encoding in developing complex quantum networks.”

Next, the authors plan to generate spin-to-path encoding and spin-spin entanglement on chip by precisely controlling the position of the quantum dots in the cross waveguide and exploring different chiral couplings. In the long run, they hope to use this system to implement on-chip entangled photons with a biexciton-exciton recombination in a single quantum dot.

“The growing understanding of chiral effects can deepen the comprehension of chiral light-matter interactions and thus advance their applications in quantum technology,” Xu said.

Source: “Position-dependent chiral coupling between single quantum dots and cross waveguides,” by Shan Xiao, Shiyao Wu, Xin Xie, Jingnan Yang, Wenqi Wei, Shushu Shi, Feilong Song, Sibai Sun, Jianchen Dang, Longlong Yang, Yunuan Wang, Zhanchun Zuo, Ting Wang, Jianjun Zhang, and Xiulai Xu, Applied Physics Letters (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0042480 .

This paper is part of the open Non-Classical Light Emitters and Single-Photon Detectors Collection, learn more here .

Submission Deadline: February 28, 2021.