image: Figure 1 | A single-photon source based on topological bulk cavity with high efficiency. a Schematic of the single-photon source, featuring a single quantum dot (QD) coupled to a ‘Q’-shaped topological bulk cavity. Inset: Unit cells of trivial and non-trivial PCs. b Auto-correlation measurement for QD emitted photons. c Simulated extraction efficiency of the optimized single-photon source as a function of NA. Inset: Angle-resolved far-field |E|2 distribution of the optimized structure.
Credit: Xin-Rui Mao, Wei-Jie Ji et al.
Quantum Photonics Group of BAQIS, led by Chief Scientist Dr Zhiliang Yuan and in collaboration with the Institute of Semiconductors CAS, has recently published a research article entitled “A single-photon source based on topological bulk cavity” in the prestigious journal of Light: Science & Applications, reporting a single-photon source based on topological bulk cavity, achieving high extraction efficiency and robust QD-cavity interaction against irregular cavity boundaries.
Topological photonics offers the potential to develop quantum light sources with inherent robustness against structural disorders. To date, topologically protected edge or corner states have been investigated for this purpose. Here, for the first time, we exploit a topological bulk state with vertical directionality to enhance the light emission from a single semiconductor quantum dot (QD). An irregular ‘Q’-shaped cavity is applied for establishing topological robustness. The optimized cavity structure integrated with a reflector predicts a high single-photon extraction efficiency up to 92%.
We experimentally demonstrate a 1.6-fold Purcell enhancement of single-photon emission in the topological bulk cavity, with tolerance to the emission wavelength or the positioning of the coupled QD. Simulations indicate that such a QD-cavity coupling system can retain a Purcell factor exceeding 1.6 under a broad spectral detuning range of 8.6 nm or a coverage area of 2.5 μm2. Our results offer a novel approach to develop topologically protected quantum light sources with high extraction efficiency and robust QD-cavity interaction against irregular cavity boundaries.
Journal
Light Science & Applications
Article Title
A single-photon source based on topological bulk cavity