Ferroelectric control of diverse hyperbolic polaritons in the visible spectrum

Abstract

Low-dimensional van der Waals materials have attracted tremendous attention due to their exceptional physical, chemical, and mechanical properties, particularly their strong anisotropy in structural, electronic, and optical behaviors. Herein, we comprehensively studied diverse hyperbolic polaritons in quasi-one-dimensional ferroelectric material WOBr₄, including their propagation patterns and frequencies, most notably, the electric-field and strain-driven elliptic-to-hyperbolic topological transition. Under moderate uniaxial strain or electric field, the optical absorption along the chain direction displays a threefold modulation in intensity and an approximately 1 eV frequency shift, while showing minor variation in the direction perpendicular to the chain. The pronounced tunability of anisotropic optical absorption is achieved through the regulation of 1D ferroelectric polarization by external stimuli, which controls the symmetry breaking of atomic orbitals involved in the optical transitions. We propose WOBr₄ as a versatile platform for ferroelectric control of hyperbolic polaritons, offering potential for advanced applications in photovoltaics, optoelectronics, and nanophotonics.