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Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation

Taboada-Gutierrez, Javier; Alvarez-Perez, Gonzalo; Duan, Jiahua; Ma, Weiliang; Crowley, Kyle; Prieto, Ivan; Bylinkin, Andrei; Autore, Marta; Volkova, Halyna; Kimura, Kenta; Kimura, Tsuyoshi; Berger, M. -H.; Li, Shaojuan; Bao, Qiaoliang; Gao, Xuan P. A.; Er

NATURE MATERIALS
2020
VL / 19 - BP / 964 - EP / +
abstract
The spectral range of long-lived and confined phonon polaritons in a polar van der Waals crystal is shown to be tunable by intercalation of Na atoms, expanding their potential for nanophotonic applications in the mid-infrared domain. Phonon polaritons-light coupled to lattice vibrations-in polar van der Waals crystals are promising candidates for controlling the flow of energy on the nanoscale due to their strong field confinement, anisotropic propagation and ultra-long lifetime in the picosecond range(1-5). However, the lack of tunability of their narrow and material-specific spectral range-the Reststrahlen band-severely limits their technological implementation. Here, we demonstrate that intercalation of Na atoms in the van der Waals semiconductor alpha-V2O5 enables a broad spectral shift of Reststrahlen bands, and that the phonon polaritons excited show ultra-low losses (lifetime of 4 +/- 1 ps), similar to phonon polaritons in a non-intercalated crystal (lifetime of 6 +/- 1 ps). We expect our intercalation method to be applicable to other van der Waals crystals, opening the door for the use of phonon polaritons in broad spectral bands in the mid-infrared domain.

AccesS level

Green submitted

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