Gate-Tuning Hybrid Polaritons in Twisted α-MoO3/Graphene Heterostructures

Zhou Zhou; Renkang Song; Junbo Xu; Xiang Ni; Zijia Dang; Zhichen Zhao; Jiamin Quan; Siyu Dong; Weida Hu; Di Huang; Ke Chen; Zhanshan Wang; Xinbin Cheng; Markus B Raschke; Andrea Alù; Tao Jiang

doi:10.1021/acs.nanolett.3c03769

Gate-Tuning Hybrid Polaritons in Twisted α-MoO₃/Graphene Heterostructures

Nano Lett. 2023 Dec 13;23(23):11252-11259. doi: 10.1021/acs.nanolett.3c03769. Epub 2023 Nov 10.

Authors

Zhou Zhou^{1

2}, Renkang Song¹, Junbo Xu¹, Xiang Ni^{3

4}, Zijia Dang⁵, Zhichen Zhao¹, Jiamin Quan^{3

6}, Siyu Dong¹, Weida Hu⁷, Di Huang¹, Ke Chen⁵, Zhanshan Wang^{1

2}, Xinbin Cheng^{1

2}, Markus B Raschke⁸, Andrea Alù^{3

6}, Tao Jiang¹

Affiliations

¹ MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
² Shanghai Institute of Intelligent Science and Technology, Tongji University, Shanghai 200092, China.
³ Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States.
⁴ School of Physics, Central South University, Changsha, Hunan 410083, China.
⁵ Center for the Physics of Low-Dimensional Materials, School of Physics and Electronics, School of Future Technology, Henan University, Kaifeng 475004, China.
⁶ Physics Program, Graduate Center, City University of New York, New York, New York 10026, United States.
⁷ State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
⁸ Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States.

PMID: 37948605
DOI: 10.1021/acs.nanolett.3c03769

Abstract

Modulating anisotropic phonon polaritons (PhPs) can open new avenues in infrared nanophotonics. Promising PhP dispersion engineering through polariton hybridization has been demonstrated by coupling gated graphene to single-layer α-MoO₃. However, the mechanism underlying the gate-dependent modulation of hybridization has remained elusive. Here, using IR nanospectroscopic imaging, we demonstrate active modulation of the optical response function, quantified in measurements of gate dependence of wavelength, amplitude, and dissipation rate of the hybrid plasmon-phonon polaritons (HPPPs) in both single-layer and twisted bilayer α-MoO₃/graphene heterostructures. Intriguingly, while graphene doping leads to a monotonic increase in HPPP wavelength, amplitude and dissipation rate show transition from an initially anticorrelated decrease to a correlated increase. We attribute this behavior to the intricate interplay of gate-dependent components of the HPPP complex momentum. Our results provide the foundation for active polariton control of integrated α-MoO₃ nanophotonics devices.

Keywords: dispersion; gate−tuning; hybrid plasmon−phonon polaritons; s-SNOM; twisted α-MoO3.