  In this study, we investigate the phenomenon of mode conversion in elastic
bulk waves using coupled hexapole resonances. A metamaterial slab is proposed
enabling the complete conversion between longitudinal and transverse modes.
Each unit of the elastic metamaterial slab comprises a pair of scatterers, and
their relative direction is oriented at an oblique angle. The interaction
between the coupled hexapoles and the background results in oblique
displacements, which are responsible for the mode conversion. Moreover, this
conversion exhibits a broader frequency range compared to the quadrupole
resonance. This innovative design significantly broadens the range of
possibilities for developing mode-converting metamaterials.
