Palombo Blascetta Nicola, Liebel Matz, Lu Xiaobo, Taniguchi Takashi, Watanabe Kenji, Efetov Dmitri K, van Hulst Niek F
ICFO - Institut de Ciences Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain.
National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Nano Lett. 2020 Mar 11;20(3):1992-1999. doi: 10.1021/acs.nanolett.9b05268. Epub 2020 Feb 21.
Defect centers in two-dimensional hexagonal boron nitride (hBN) are drawing attention as single-photon emitters with high photostability at room temperature. With their ultrahigh photon-stability, hBN single-photon emitters are promising for new applications in quantum technologies and for 2D-material based optoelectronics. Here, we control the emission rate of hBN-defects by coupling to resonant plasmonic nanocavities. By deterministic control of the antenna, we acquire high-resolution emission maps of the single hBN-defects. Using time-gating, we can discriminate the hBN-defect emission from the antenna luminescence. We observe sharp dips (40 nm fwhm) in emission, together with a reduction in luminescence lifetime. Comparing with finite-difference time-domain simulations, we conclude that both radiative and nonradiative rates are enhanced, effectively reducing the quantum efficiency. Also, the large refractive index of hBN largely screens off the local antenna field enhancement. Finally, based on the insight gained we propose a close-contact design for an order of magnitude brighter hBN single-photon emission.
二维六方氮化硼（hBN）中的缺陷中心作为室温下具有高光稳定性的单光子发射器正受到关注。凭借其超高的光子稳定性，hBN单光子发射器在量子技术的新应用以及基于二维材料的光电子学方面具有广阔前景。在此，我们通过与共振等离子体纳米腔耦合来控制hBN缺陷的发射速率。通过对天线的确定性控制，我们获得了单个hBN缺陷的高分辨率发射图谱。使用时间选通，我们可以区分hBN缺陷发射和天线发光。我们观察到发射出现尖锐的下降（半高宽40 nm），同时发光寿命缩短。与时域有限差分模拟结果比较后，我们得出结论，辐射和非辐射速率均增强，有效降低了量子效率。此外，hBN的大折射率在很大程度上屏蔽了局部天线场增强。最后，基于所获得的见解，我们提出了一种紧密接触设计，以使hBN单光子发射亮度提高一个数量级。
