分类： 光学 >> 量子光学 提交时间： 2023-02-19
Xin Xie
Sai Yan
Jianchen Dang
Jingnan Yang
Shan Xiao
Yunuan Wang
Shushu Shi
Longlong Yang
Danjie Dai
Yu Yuan
Nan Luo
Ting Cui
Gaohong Chi
Zhanchun Zuo
Bei-Bei Li
Can Wang
Xiulai Xu
摘要： Slow light in topological valley photonic crystal structures offers new possibilities to enhance light-matter interaction. We report a topological cavity based on slow light topological edge mode for broadband Purcell enhancement. The topological edge modes with large group indices over 100 can be realized with a bearded interface between two topologically distinct valley photonic crystals, featuring the greatly enhanced Purcell factor because of the increased local density of states. In the slow light regime, the topological cavity supports much more cavity modes with higher quality factor than that in the fast light regime, which is both demonstrated theoretically and experimentally. We demonstrate the cavity enables the broadband Purcell enhancement together with substantial Purcell factor, benefiting from dense cavity modes with high quality factor in a wide spectral range. It has great benefit to the realization of high-efficiency quantum-dot-based single-photon sources and entangled-photon sources with less restriction on spectral match. Such topological cavity could serve as a significant building block toward the development of photonic integrated circuits with embedded quantum emitters.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Shan Xiao
Shiyao Wu
Xin Xie
Jingnan Yang
Wenqi Wei
Shushu Shi
Feilong Song
Sibai Sun
Jianchen Dang
Longlong Yang
Yunuan Wang
Sai Yan
Zhanchun Zuo
Ting Wang
Jianjun Zhang
Kuijuan Jin
Xiulai Xu
摘要： Chiral quantum optics has attracted considerable interest in the field of quantum information science. Exploiting the spin-polarization properties of quantum emitters and engineering rational photonic nanostructures has made it possible to transform information from spin to path encoding. Here, compact chiral photonic circuits with deterministic circularly polarized chiral routing and beamsplitting are demonstrated using two laterally adjacent waveguides coupled with quantum dots. Chiral routing arises from the electromagnetic field chirality in waveguide, and beamsplitting is obtained via the evanescent field coupling. The spin- and position-dependent directional spontaneous emission are achieved by spatially selective micro-photoluminescence measurements, with a chiral contrast of up to 0.84 in the chiral photonic circuits. This makes a significant advancement for broadening the application scenarios of chiral quantum optics and developing scalable quantum photonic networks.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Xin Xie
Jianchen Dang
Sai Yan
Weixuan Zhang
Huiming Hao
Shan Xiao
Shushu Shi
Zhanchun Zuo
Haiqiao Ni
Zhichuan Niu
Xiangdong Zhang
Can Wang
Xiulai Xu
摘要： The second-order topological photonic crystal with 0D corner state provides a new way to investigate cavity quantum electrodynamics and develop topological nanophotonic devices with diverse functionalities. Here, we report on the optimization and robustness of topological corner state in the second-order topological photonic crystal both in theory and in experiment. The topological nanocavity is formed based on the 2D generalized Su-Schrieffer-Heeger model. The quality factor of corner state is optimized theoretically and experimentally by changing the gap between two photonic crystals or just modulating the position or size of the airholes surrounding the corner. The fabricated quality factors are further optimized by the surface passivation treatment which reduces surface absorption. A maximum quality factor of the fabricated devices is about 6000, which is the highest value ever reported for the active topological corner state. Furthermore, we demonstrate the robustness of corner state against strong disorders including the bulk defect, edge defect, and even corner defect. Our results lay a solid foundation for the further investigations and applications of the topological corner state, such as the investigation of strong coupling regime and the development of optical devices for topological nanophotonic circuitry.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Jingnan Yang
Shushu Shi
Xin Xie
Shiyao Wu
Shan Xiao
Feilong Song
Jianchen Dang
Sibai Sun
Longlong Yang
Yunuan Wang
Zi-Yong Ge
Bei-Bei Li
Zhanchun Zuo
Kuijuan Jin
Xiulai Xu
摘要： We report on controllable cavity modes through controlling the backscattering by two identical scatterers. Periodic changes of the backscattering coupling between two degenerate cavity modes are observed with the angle between two scatterers and elucidated by a theoretical model using two-mode approximation and numerical simulations. The periodically appearing single-peak cavity modes indicate mode degeneracy at diabolical points. Then interactions between single quantum dots and cavity modes are investigated. Enhanced emission of a quantum dot with a six-fold intensity increase is obtained in a microdisk at a diabolical point. This method to control cavity modes allows large-scale integration, high reproducibility and fexible design of the size, location, quantity and shape for scatterers, which can be applied for integrated photonic structures with scatterer-modified light-matter interaction.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Longlong Yang
Xin Xie
Jingnan Yang
Mengfei Xue
Shiyao Wu
Shan Xiao
Feilong Song
Jianchen Dang
Sibai Sun
Zhanchun Zuo
Jianing Chen
Yuan Huang
Xingjiang Zhou
Kuijuan Jin
Can Wang
Xiulai Xu
摘要： Strong exciton-plasmon interaction between the layered two-dimensional (2D) semiconductors and gap plasmons shows a great potential to implement cavity quantum-electrodynamics in ambient condition. However, achieving a robust plasmon-exciton coupling with nanocavity is still very challenging, because the layer area is usually small with conventional approaches. Here, we report on a robust strong exciton-plasmon coupling between the gap mode of bowtie and the excitons in MoS$_2$ layers with gold-assisted mechanical exfoliation and the nondestructive wet transfer techniques for large-area layer. Benefiting from the ultrasmall mode volume and strong in-plane field, the estimated effective exciton number contributing to the coupling is largely reduced. With a corrected exciton transition dipole moment, the exciton numbers are extracted with 40 for the case of monolayer and 48 for 8 layers. Our work paves a way to realize the strong coupling with 2D materials with few excitons at room temperature.
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