Resumen: Anisotropic planar polaritons - hybrid electromagnetic modes mediated by phonons, plasmons, or excitons - in biaxial two-dimensional (2D) van der Waals crystals have attracted significant attention due to their fundamental physics and potential nanophotonic applications. In this Perspective, we review the properties of planar hyperbolic polaritons and the variety of methods that can be used to experimentally tune them. We argue that such natural, planar hyperbolic media should be fairly common in biaxial and uniaxial 2D and 1D van der Waals crystals, and identify the untapped opportunities they could enable for functional (i.e. ferromagnetic, ferroelectric, and piezoelectric) polaritons. Lastly, we provide our perspectives on the technological applications of such planar hyperbolic polaritons. Idioma: Inglés DOI: 10.1038/s41467-023-43992-8 Año: 2024 Publicado en: Nature communications 15 (2024), 69 [14 pp.] ISSN: 2041-1723 Factor impacto JCR: 15.7 (2024) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 10 / 135 = 0.074 (2024) - Q1 - T1 Factor impacto SCIMAGO: 4.761 - Biochemistry, Genetics and Molecular Biology (miscellaneous) (Q1) - Physics and Astronomy (miscellaneous) (Q1) - Chemistry (miscellaneous) (Q1)