Meunier Max, Eng John J H, Mu Zhao, Chenot Sebastien, Brändli Virginie, de Mierry Philippe, Gao Weibo, Zúñiga-Pérez Jesús
Université Côte d'Azur, Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur l'Hétéro Epitaxie et ses Applications (CRHEA), Rue Bernard Gregory, 06560 Valbonne, France.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, SPMS-PAP-03-06, 21 Nanyang Link 637371, Singapore.
Nanophotonics. 2023 Feb 20;12(8):1405-1419. doi: 10.1515/nanoph-2022-0659. eCollection 2023 Apr.
The ideal single-photon source displaying high brightness and purity, emission on-demand, mature integration, practical communication wavelength (i.e., in the telecom range), and operating at room temperature does not exist yet. In 2018, a new single-photon source was discovered in gallium nitride (GaN) showing high potential thanks to its telecom wavelength emission, record-high brightness, good purity, and operation at room temperature. Despite all these assets, its coupling to photonic structures has not been achieved so far. In this article, we make a first step in this direction. First, we analyze whether stacking faults are indeed a necessary condition for obtaining such emitters in GaN layers. Then, we discuss the challenges associated to a low spatial density and to a spectrally wide distribution of emitters, which necessitate their location to be determined beforehand and the photonic structure resonance to be tuned to their emission wavelength. The design and fabrication of bullseye antennas are thoroughly described. Finally, we fabricate such bullseyes around telecom emitters and demonstrate that the embedded emitters are able to sustain the necessary clean-room process and still operate as single-photon emitters after the fabrication steps, with room-temperature purities up to 99% combined with repetition rates in the order of hundreds of kHz. The findings in this work demonstrate that telecom single-photon emitters in GaN operating at room temperature are well adapted for single-photon applications where brightness and purity are the required figures of merit, but highlight the numerous difficulties that still need to be overcome before they can be exploited in actual quantum photonic applications.
理想的单光子源应具备高亮度和纯度、按需发射、成熟的集成度、实用的通信波长（即在电信波段）且能在室温下工作，但目前尚未出现。2018年，氮化镓（GaN）中发现了一种新的单光子源，由于其电信波长发射、创纪录的高亮度、良好的纯度以及在室温下工作，显示出很高的潜力。尽管有这些优点，但到目前为止，它与光子结构的耦合尚未实现。在本文中，我们朝着这个方向迈出了第一步。首先，我们分析层错是否确实是在GaN层中获得此类发射器的必要条件。然后，我们讨论与发射器的低空间密度和光谱宽分布相关的挑战，这需要预先确定它们的位置，并将光子结构共振调谐到它们的发射波长。详细描述了靶心天线的设计和制造。最后，我们在电信发射器周围制造了这样的靶心，并证明嵌入的发射器能够承受必要的洁净室工艺，并且在制造步骤之后仍能作为单光子发射器工作，室温纯度高达99%，重复率在数百千赫兹量级。这项工作的结果表明，室温下工作的GaN中的电信单光子发射器非常适合于以亮度和纯度为所需品质因数的单光子应用，但也突出了在实际量子光子应用中利用它们之前仍需克服的众多困难。
