Hyperbolic whispering-gallery phonon polaritons in boron nitride nanotubes

Xiangdong Guo; Ning Li; Xiaoxia Yang; Ruishi Qi; Chenchen Wu; Ruochen Shi; Yuehui Li; Yang Huang; F Javier García de Abajo; En-Ge Wang; Peng Gao; Qing Dai

doi:10.1038/s41565-023-01324-3

Hyperbolic whispering-gallery phonon polaritons in boron nitride nanotubes

Nat Nanotechnol. 2023 May;18(5):529-534. doi: 10.1038/s41565-023-01324-3. Epub 2023 Feb 23.

Authors

Xiangdong Guo^#^{1

2}, Ning Li^#³, Xiaoxia Yang^{4

5}, Ruishi Qi³, Chenchen Wu^{1

2}, Ruochen Shi³, Yuehui Li³, Yang Huang⁶, F Javier García de Abajo^{7

8}, En-Ge Wang^{9

10

11}, Peng Gao^{12

13}, Qing Dai^{14

15}

Affiliations

¹ CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China.
³ International Center for Quantum Materials, Electron Microscopy Laboratory, School of Physics, Academy for Advanced Interdisciplinary Studies, Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
⁴ CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China. [email protected].
⁵ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China. [email protected].
⁶ School of Materials Science and Engineering, Hebei Key Laboratory of Boron Nitride Micro and Nano Materials, Hebei University of Technology, Tianjin, China.
⁷ ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain. [email protected].
⁸ ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain. [email protected].
⁹ Collaborative Innovation Center of Quantum Matter, Beijing, China.
¹⁰ Songshan Lake Materials Lab, Institute of Physics, Chinese Academy of Sciences, Guangdong, China.
¹¹ School of Physics, Liaoning University, Shenyang, China.
¹² International Center for Quantum Materials, Electron Microscopy Laboratory, School of Physics, Academy for Advanced Interdisciplinary Studies, Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China. [email protected].
¹³ Collaborative Innovation Center of Quantum Matter, Beijing, China. [email protected].
¹⁴ CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China. [email protected].
¹⁵ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China. [email protected].

^# Contributed equally.

PMID: 36823369
DOI: 10.1038/s41565-023-01324-3

Abstract

Light confinement in nanostructures produces an enhanced light-matter interaction that enables a vast range of applications including single-photon sources, nanolasers and nanosensors. In particular, nanocavity-confined polaritons display a strongly enhanced light-matter interaction in the infrared regime. This interaction could be further boosted if polaritonic modes were moulded to form whispering-gallery modes; but scattering losses within nanocavities have so far prevented their observation. Here, we show that hexagonal BN nanotubes act as an atomically smooth nanocavity that can sustain phonon-polariton whispering-gallery modes, owing to their intrinsic hyperbolic dispersion and low scattering losses. Hyperbolic whispering-gallery phonon polaritons on BN nanotubes of ～4 nm radius (sidewall of six atomic layers) are characterized by an ultrasmall nanocavity mode volume (V_m ≈ 10^-10λ₀³ at an optical wavelength λ₀ ≈ 6.4 μm) and a Purcell factor (Q/V_m) as high as 10¹². We posit that BN nanotubes could become an important material platform for the realization of one-dimensional, ultrastrong light-matter interactions, with exciting implications for compact photonic devices.

Abstract

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