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arXiv · 2408.09811

Unveiling the Mechanism of Phonon-Polariton Damping in \alpha-MoO_3

Javier Taboada-Gutiérrez·Yixi Zhou·Ana I. F. Tresguerres-Mata·Christian Lanza·Abel Martínez-Suárez·Gonzalo Álvarez-Pérez·Jiahua Duan·José Ignacio Martín·María Vélez·Iván Prieto·Adrien Bercher·Jérémie Teyssier·Ion Errea·Alexey Y. Nikitin·Javier Martín-Sánchez·Alexey B. Kuzmenko·Pablo Alonso-González
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Abstract

Phonon polaritons (PhPs) (light coupled to lattice vibrations) in the highly anisotropic polar layered material molybdenum trioxide (\alpha-MoO_3) are currently the focus of intense research efforts due to their extreme subwavelength field confinement, directional propagation and unprecedented low losses. Nevertheless, prior research has primarily concentrated on exploiting the squeezing and steering capabilities of \alpha-MoO_3 PhPs, without inquiring much into the dominant microscopic mechanism that determines their long lifetimes, key for their implementation in nanophotonic applications. This study delves into the fundamental processes that govern PhP damping in \alpha-MoO_3 by combining ab initio calculations with scattering-type scanning near-field optical microscopy (s-SNOM) and Fourier-transform infrared (FTIR) spectroscopy measurements across a broad temperature range (from 8 to 300 K). The remarkable agreement between our theoretical predictions and experimental observations allows us to identify third-order anharmonic phonon-phonon scattering as the main damping mechanism of \alpha-MoO_3 PhPs. These findings shed light on the fundamental limits of low-loss PhPs, a crucial factor for assessing their implementation into nanophotonic devices.

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Javier Taboada-Gutiérrez, Yixi Zhou, Ana I. F. Tresguerres-Mata, Christian Lanza, Abel Martínez-Suárez, Gonzalo Álvarez-Pérez, Jiahua Duan, José Ignacio Martín, María Vélez, Iván Prieto, Adrien Bercher, Jérémie Teyssier, Ion Errea, Alexey Y. Nikitin, Javier Martín-Sánchez, Alexey B. Kuzmenko, Pablo Alonso-González. 2024-08-19. Unveiling the Mechanism of Phonon-Polariton Damping in \alpha-MoO_3. https://doi.org/10.1021/acsphotonics.4c00485

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