This paper introduces a new class of mid-infrared nanoresonators based on phonon polaritons (PhPs) in α-MoO3 van der Waals crystals. These resonators exhibit low losses (quality factors up to 200) and a unique twist-tunable spectral response, allowing control of their resonances (up to 32 cm⁻¹) by simply rotating the crystal. This tunability, achieved by placing an α-MoO3 slab on a metallic ribbon array, opens avenues for tunable and low-loss infrared nanotechnologies.

O. G. Matveeva, A. I. F. Tresguerres-Mata, R. V. Kirtaev, K. V. Voronin, J. Taboada-Gutiérrez, C. Lanza, J. Duan, J. Martín-Sánchez, V. S. Volkov, P. Alonso-González, A. Y. Nikitin